Showing papers in "Journal of the Kansas Entomological Society in 1990"

Biosynthesis and chemical mimicry of cuticular hydrocarbons from the obligate predator, Microdon albicomatus Novak (Diptera: Syrphidae) and its ant prey, Myrmica incompleta Provancher (Hymenoptera: Formicidae).

Abstract: The cuticular hydrocarbons of larval Microdon albicomatus, a predatory syrphid fly, are qualitatively identical to those of its prey, the pupae of the myrmicine ant, Myrmica incompleta. Eighteen hydrocarbon components were identified, including n-al kanes, 3-methyl alkanes, 11and 13-methyl alkanes, a single dimethyl alkane (5,17-di methyl pentacosane) and two Z-9-monoenes (23:1 and 25:1). The cuticular hydrocarbons of worker M. incompleta were also identified and shown to contain the same components as the ant pupae, but in different relative abundances. A radiolabelling experiment using 1 14C-acetate with the Microdon larvae indicated that the fly biosynthesizes its hydrocarbons rather than procuring them from its prey. Although most social insects maintain a closed society that excludes all but their own conspecific colony members (Wilson, 1971), there are numerous ex amples in which inquilines have more or less successfully integrated themselves into the life of the colony (Kistner, 1979). The exact mechanism by which they achieve this integration has long been a subject of interest, and current thought implicates primarily chemical stimuli (Howard and Blomquist, 1982; Stowe, 1988). Cuticular hydrocarbons have been postulated to be the major chemical class involved, and they have been hypothesized to function in a process of chemical mimicry (Howard et al., 1978, 1980, 1982, 1982a, 1990; Bonavita-Couggourdan et al., 1987; Vander Meer and Wojcik, 1982). Most of the literature on chemical mimicry of cuticular hydrocarbons deals with highly integrated host-specific termitophiles that have a mutualistic rela tionship with their hosts. Since it has also been shown that most social insects have species-specific cuticular hydrocarbon profiles (Howard and Blomquist, 1982; Stowe, 1988) the evolutionary pathway to chemical mimicry by these termito philes would seem to be relatively straightforward. Compared to termitophiles, however, most myrmecophiles are rarely host-specific at the species level and often not even at the generic level. Furthermore, many myrmecophiles are not mutualists, but rather either parasites or predators of their hosts (Kistner, 1979). How chemical mimicry of their hosts' cuticular hydrocarbons could evolve in these systems is less clear. Indeed, as noted by Howard et al. (1990) some of the myrmecophiles reportedly utilizing chemical mimicry (Vander Meer et al., 1989) are likely utilizing a process of chemical camouflage instead (that is, they are not 1 USDA-ARS, U.S. Grain Marketing Research Laboratory, 1515 College Avenue, Manhattan, KS 66502. Author to whom reprint requests should be submitted. 2 Department of Entomology, 202 Plant Industry Building, University of Nebraska-East Campus, Lincoln, NE 68583-0816. 3 Department of Entomology, Washington State University, Pullman, WA 99164-6432. Accepted for publication 3 May 1990. This content downloaded from 157.55.39.17 on Thu, 01 Sep 2016 05:08:52 UTC All use subject to http://about.jstor.org/terms 438 JOURNAL OF THE KANSAS ENTOMOLOGICAL SOCIETY de novo biosynthesizing the requisite hydrocarbons, but rather passively acquiring them from their hosts). Larvae of all known species of the syrphid genus Microdon are inquilines in the nests of social insects, and all North American species live with ants (Wheeler, 1908; Akre et al., 1990). Biologies of only a few Microdon species are known in detail, but in every case the immatures are obligate predators on the brood of their hosts (Van Pelt and Van Pelt, 1972; Duffield, 1981; Garnett et al., 1985; Akre et al., 1988). Host workers, however, rarely attack the fly larvae which are apparently perceived by them as ant brood. We earlier reported that larvae of Microdon piperi Knab, a common western North American syrphid fly, possesses exactly the same cuticular hydrocarbons as its principal ant host, Camponotus modoc Wheeler, and we postulated that this was a bona fide case of chemical mimicry (Howard et al., 1990). In that study, however, we were unable to conduct any biosynthesis experiments to directly demonstrate that the fly produced its own hydrocarbons rather than procuring them from its host. We now report that a second Microdon species associated with an ant in a different subfamily also contains exactly the same cuticular hydrocarbons as its host, and that radiola belling data shows that this fly biosynthesizes its own hydrocarbons, thus pro viding strong support for chemical mimicry rather than chemical camouflage. Materials and Methods insects: Second and third instars of Microdon albicomatus Novak and workers and brood of Myrmica incompleta Provancher were collected from a fallen log at about 1000 m elevation in Latah Co., Idaho in July 1989 and transported back to the laboratory in vials containing a small amount of moistened plaster-of-paris/ charcoal mixture. Moist wood debris from the collection site was also added to provide a substrate. Insects were used within two weeks of collection for bio chemical analyses. A sample of host ants and fly larvae were preserved in 70% ethanol, and voucher specimens were deposited in the M. T. James Insect Col lection of the Department of Entomology, Washington State University, Pullman, Washington. chemical analyses: Insects were killed by freezing and cuticular lipids ex tracted by immersing the insects in three successive portions of hexane for one minute each time. Since our previous studies had shown that individual fly larvae contain only small quantities of hydrocarbon, for the Microdon extraction 93 third instars were used as one sample; for the Myrmica brood, three replicate samples of five pupae each were used, and for Myrmica workers, three replicate samples of 15 individuals were used. The combined portions from each replicate were concentrated under a gentle stream of N2, and hydrocarbons were isolated by chromatography on a 3-cm "minicolumn" of Biosil A (Bio-Rad Laboratories, Richmond, California)4 as described earlier (Howard et al., 1978). Mass spectral analyses were conducted using a Hewlett-Packard 5790A GC containing a 10 m by 0.19 mm I.D. DB-5 bonded phase capillary column (J and W Scientific, Folsom, California) connected to a Hewlett-Packard 5970 Mass Selective Detector (MSD) and a Hewlett-Packard 9133 Data System. Ultrapure 4 This article reports the results of research only. Mention of a proprietary product does not constitute an endorsement or recommendation for its use by the USDA. This content downloaded from 157.55.39.17 on Thu, 01 Sep 2016 05:08:52 UTC All use subject to http://about.jstor.org/terms VOLUME 63, NUMBER 3 439 helium was the carrier gas, with a column head pressure of 3.5 kg/cm2 and electron impact mass spectra were obtained at 70 eV. Analyses were done using temper ature programming, with an initial temperature of 200?C, a final temperature of 320?C and a program rate of 5?C/minute. Signals from the MSD were stored and peak areas from the total ion trace were extracted and used for percent composition analyses. Retention times of each hydrocarbon component and equivalent chain length (ECL) values were obtained by comparison to known n-alkane standards (Howard et al., 1978). Individual components were identified from their char acteristic EI-MS fragmentation patterns (Jackson and Blomquist, 1976; Nelson, 1978). Double bond locations in alkenes were obtained by preparing dithiomethyl ethers (Francis and Veland, 1981) and examining their electron impact mass spectra. Stereochemistry of the parent alkene was inferred by comparison of the retention time of the dithiomethyl ethers to known standards. INCORPORATION OF RADIOACTIVE ACETATE INTO CUTICULAR HYDROCARBONS OF Microdon albicomatus: l-14C-acetate, specific activity 40-60 mCi/mmole (Amersham Inc., Arlington Heights, Illinois) was made up in 100% ethanol to 7.5 ixCi/ixl. Two replicates of 14 second/third instars of M albicomatus were placed in tissue grinders in insect saline solution, 2 ?? l-14C-acetate added, the insects homogenized at medium speed for 30 seconds, then incubated at 23?C for 30 minutes and total lipids extracted by the method of Bligh and Dyer (1959). The total lipid extracts were dried under a stream of N2, then applied to a 0.25 mm silica gel thin layer Chromatographie plate (Aldrich, Inc., Milwaukee, Wisconsin). The plate was developed in petroleum ether:ethyl ether:acetic acid (80:20:1, v/v) and individual lipid classes were recognized by comparison to co-chroma tographed lipid standards (Sigma Chemical Co., St. Louis, Missouri). The hydro carbon band was scraped into a liquid scintillation vial and radioactivity was assayed by liquid scintillation counting on a Pharmacia-LKB 1209 Liquid Scin tillation Counter (Gaithersburg, Maryland) equipped with chemiluminescence discrimination at 96% counting efficiency for 14C.

The development and use of pitfall and probe traps for capturing insects in stored grain.

Abstract: The development and use of pitfall and probe traps for capture of insects in bulk-stored grain are outlined. Unbaited traps are effective in detecting infestations and they detect a large number of species compared with grain-sampling devices. The effec tiveness of the traps is related to temperature, trapping period, and grain moisture content; and traps are less reliable for detecting insect species that are less mobile, have a non uniform distribution in grain, feed within kernels, or can escape from the traps. Compar isons are given between effectiveness of probe traps and grain sampling for detecting insects, and experience using probe traps in stored grain is reported. The use of traps is a relatively new method of detecting insects in bulk-stored grain (Loschiavo and Atkinson, 1967). The traps, whether simple pitfalls at the grain surface (Watters and Cox, 1957) or probe traps under the grain surface, offer numerous advantages (Loschiavo and Atkinson, 1973) over the standard sampling procedure of collecting small volumes of grain and sifting or incubating them, or extracting insects in Berlese funnels. The traps are simple to use, are escape-proof to many species, and provide a mechanism for continuous monitoring for stored product insects. Monitoring over time gives a quick indication of population growth without taking grain samples. Adult beetles are captured live in the traps. Detecting low insect densities, the traps can give early warning of potential insect problems (Wright et al., 1988). The success of control measures can also be accurately assessed (Pinniger, 1988). The traps have several advantages over the standard sampling procedures, notably the sensitivity of insect detection. However, there are several potential problems associated with the use of the traps. Their sensitivity may be a disad vantage in countries which have a legally-defined zero tolerance for all live insects in export grain such as Canada or Australia. This problem may often be less severe in countries such as the United States which at present have a defined economic threshold for insects in stored grain, which is based on grain samples. Relating numbers of insects captured in traps with absolute numbers per volume of grain needs to be addressed (Lippert and Hagstrum, 1987). Other problems related to interpreting numbers of insects captured and use of the traps will also be discussed in this review. Probe traps offer an extremely useful tool in scientific research and surveys, 1 Agriculture Canada Research Station, 195 Dafoe Road, Winnipeg, Manitoba, Canada R3T 2M9. 2 USDA-ARS, Stored-Product Insect Research and Development Lab., P.O. Box 22909, Savannah, Georgia 31403. 3 3315 Gardner Hall, North Carolina State University, Raleigh, North Carolina 27607. 4 Department of Entomology, University of Minnesota, St. Paul, Minnesota 55108. 5 Department of Entomology, Waters Hall, Kansas State University, Manhattan, Kansas 66506. 6 Retired, Agriculture Canada Research Station, 195 Dafoe Road, Winnipeg, Manitoba, Canada R3T 2M9. Accepted for publication 15 July 1990. This content downloaded from 157.55.39.243 on Thu, 06 Oct 2016 04:53:18 UTC All use subject to http://about.jstor.org/terms VOLUME 63, NUMBER 4 507 and can be used effectively by farmers and grain managers to plan management tactics. For example, the type of species present can reflect the condition of the grain. The presence of only fungus-feeding beetles will dictate different actions by managers than will infestations by grain-feeding insects. The conditions that affect capture of particular species also need to be defined. Whether these traps will ever be accepted by governmental regulatory agencies concerned with export grain quality remains to be seen. The following review covers some early uses of pitfall traps, the development of probe traps, advantages and disadvantages of probe traps, and experience obtained by using them in the field.

Overview on stored-product insect pheromones and food attractants.

Abstract: The direction of recent research into the use of pheromones and food at tractants for detection, monitoring and control of stored-product insects is considered. The value of the moth pheromones has been clearly demonstrated both within premises and outdoors. Further work on the composition of pheromones produced by moths and on trap design may be desirable. Recent progress with the beetle sex pheromones includes the design of a new Khapra beetle trap and further studies on the stereochemical complexity and inhibitory isomers of anobiid pheromones. Promising advances are also being reported with the beetle aggregation pheromones with new trap designs, newly identified components and synthetic material free from inhibitory isomers. Further study is needed to elucidate how species specificity is maintained between species whose pheromones are closely related chemically, and to investigate the synergistic interaction with food attractants. The potential of food attractants alone as non-specific lures is exemplified by work with extracts of crushed carob pods. There is a growing number of examples of the successful use of these attractants but many aspects of their effects on insects are not yet fully understood. Full exploitation of the potential of attractants for stored-product insects still needs further research in virtually every area of the subject from initial characterisation to the development of a suitably simple combination of trap and lure for practical use. Given a thorough knowledge of both trap design and the variables which affect trap catch, there may still be scope for improving trap effectiveness. For example, laboratory tests have shown that modern traps in cereal bulks may catch only a small percentage of the insects present (Cogan and Wakefield, 1987; White and Loschiavo, 1986). Significant improvements have sometimes been achieved by the use of pheromones and food attractants, which can bring advantages in any of three ways. Firstly, detection can be improved by enabling infestations to be found earlier and their extent to be defined more accurately, giving staff more time to choose and implement appropriate control measures and thus minimise pest damage. Secondly, there can be an improvement in the precision of moni toring population levels. Lastly, the use of attractants can allow the development of alternative control methods such as mass trapping. Provided the improvement outweighs the cost of obtaining it, the use of attractants should be encouraged. An incidental but important result of this work is to provide a better understanding of pest behaviour. This paper provides an overview of the subject, outlines the direction of recent research and suggests areas needing further research. It is not intended to be a comprehensive review since further information is already available. Burkholder and Ma (1985) review the use of pheromones for monitoring and control, Sinclair and Howitt (1984) discuss comparative trials and commercially available traps and pheromone lures in Australia, and Campion et al. (1987) describe various studies on the use of pheromones in developing countries. Reviews covering both pheromones and food attractants have been written by Pinniger and Chambers (1987), Chambers (1987), and Cogan and Chambers (1989). Accepted for publication 15 July 1990. This content downloaded from 207.46.13.132 on Tue, 05 Jul 2016 06:25:35 UTC All use subject to http://about.jstor.org/terms VOLUME 63, NUMBER 4 491

Factors affecting the design of traps for stored-product insects.

Abstract: The availability of pheromones for many species of stored-product insects and the need to eliminate or greatly reduce the levels of insect infestation and contamination has led to increased interest in the development of traps for detecting and monitoring these insects Traps have been developed for aerial insects (mainly pyralid moths and anobiids), for crawling stages of Coleoptera (Trogoderma, Tribolium and Oryzaephilus spp) and for insertion into bulk grain for a complex of grain-infesting Coleoptera Traps for aerial insects are most commonly sticky traps and funnel traps, modified to function in environments which may be dusty and which are observed by the public Many traps for crawling Coleoptera are of corrugated materials and are designed to cause insects seeking shelter to drop into devices or onto adhesive surfaces Food-baited traps have also been used for crawling Coleoptera Perforated probe traps for grain are pitfall drop traps which contain an internal collection device such as a funnel tube Successful traps are refinements of simple devices which utilize basic behavior to trap insects Traps, to be popular in the marketplace must be easy to use, maintain and assemble, be reliable, easily produced, and cost effective The design of traps for stored-product insects, along with and their availability and use, has received new interest which has paralleled progress in the identifi cation and synthesis of pheromones and attractants for the major pest species In addition, regulatory requirements for reduced or zero tolerance of insect infes tation, damage, and contamination, driven by public concern over the health aspects of pesticide use, have made early detection and control of insects essential Traps for the early detection, monitoring and survey of such insects have proven valuable in the continuing effort to protect food and fiber from insect damage or loss This review describes some of the basic designs of traps for stored-product insects, how they work, and how trapping environment and use patterns affect their design In addition we will present examples of the origin and development of two trap types, and finally, discuss how more practical requirements, such as commercial production, and consumer acceptance, have influenced our perception of what makes a trap design successful We will not discuss mechanized traps, which will be covered in another review Attractance to traps (using pheromones and/or food attractants) will be the subject of other authors in this series Stored-product insect traps fall into three broad categories based on deployment: 1) traps for aerial insects including sticky and funnel types; 2) surface-deployed traps for crawling insects, including harborage, sticky and pitfall types, and food Mention of a proprietary product does not constitute an endorsement or recommendation of its use by the USDA 1 Stored-product Insects Research Unit, USDA, Agricultural Research Service, Department of En tomology, University of Wisconsin, Madison, Wisconsin 53706 USA 2 Philip Morris USA, Research Center, PO Box 26583, Richmond, Virginia 23261 USA Accepted for publication 15 July 1990 This content downloaded from 2074613172 on Fri, 07 Oct 2016 05:57:24 UTC All use subject to http://aboutjstororg/terms VOLUME 63, NUMBER 4 467 or bait-bag traps; 3) traps used in grain, including sub-surface pitfall and perforated probe traps These categories become less distinct as traps are used for different purposes and for species other than those for which they were originally designed We also show that several different types are conceptually similar in the actual mechanism of entrapment It would be equally logical to categorize traps as those which catch flying adults (such as Plodia interpunctella (Hubner) and Lasioderma serricorne (Fabricius), or those which catch crawling forms (such as Oryzaephilus surinamensis (L), Tri bolium confusum Jacquelin duVal, and Trogoderma granarium Everts, etc) These classes become less rigid as well, since under certain conditions insects (such as Trogoderma variabile Ballion) may either fly or, unable to fly due to environmental or biological restraints, crawl to non-aerial traps

Female size and fecundity in the small carpenter bee, Ceratina calcarata (Robertson) (Hymenoptera: Anthophoridae).

Abstract: In the small carpenter bee, Ceratina calcarata (Robertson), female eggs are laid on provision masses that are larger than those that receive male eggs. Because there is a positive relationship between the size of the adult and the amount of food available to it as a larva, the females are larger than the males. Large size in female insects is often associated with an increase in fecundity. However, it was determined that in C. calcarata, there was no correlation between the size of the mother and either the number of brood cells in her nest or the number of eggs she laid. There was a positive correlation between a mother's size and her foraging ability judging by the size of the provision masses she stored. But larger mothers did not produce more daughters than sons as might be expected. The question of the advantage to C. calcarata mothers of making daughters larger than sons is considered. An increase in fecundity is often associated with an increase in the size or weight of a female insect (e.g., Leather and Wellings, 1981; Juliano, 1985; Leather, 1988) and this pattern is generally true for nonsocial Hymenoptera. The parasitoid, Nasonia vitripennis, shows a positive correlation between the female's body size and the number of progeny produced (Saunders, 1966). In the eumenid wasps Ancistrocerus adiabatus and Euodynerus foraminatus, Cowan (1981) found that larger females "provisioned more cells (and thus laid more eggs) than smaller females." Freeman (1981) noted a similar situation in the sphecid Sceliphron assimile. Wilmer (1985) found in another sphecid, Cerceris arenaria, that larger females had as much as twice the egg-laying success as did smaller females. However, a similar relationship between female size and fecundity was not found in the twig-nesting solitary bee Osmia lignaria propinqua (Tepedino and Torchio, 1982). They reported no correlation between female size and the number of nests produced, the number of brood cells produced, the total number of offspring produced or the number of offspring that survived. In the small twig-nesting anthophorid carpenter bee, Ceratina calcarata (Rob ertson), the female is the larger sex. The size of the adult is positively related to the amount of food it received as a larva (Johnson, 1988). Therefore, the mother must do more work (i.e., harvest more food) to produce a female offspring than to produce a male one. Thus it seems reasonable to assume that larger size is more advantageous to female offspring than to male offspring. If there is a relationship between female size and fecundity in C. calcarata then a larger female should produce more brood cells in her nest (and thus lay more eggs) than a smaller female. Furthermore, if larger females are more efficient at collecting food (Cowan, 1981; Freeman, 1981) they might also produce larger provision masses and hence larger offspring. Since females are produced on rel Accepted for publication 11 December 1989. This content downloaded from 40.77.167.44 on Fri, 10 Jun 2016 06:34:41 UTC All use subject to http://about.jstor.org/terms VOLUME 63, NUMBER 3 415 atively larger provision masses, this leads to the further possibility that the larger mothers might produce proportionally more female offspring than do smaller mothers (Fisher, 1958; Trivers and Hare, 1976). In this research, an effort was made to determine if there is a relationship between mother size and the number and sex of offspring in the nests of C calcarata. Materials and Methods C. calcarata nests used were collected in Indiana (Putnam Co.) from the woody twigs of multifloral rose (Rosa multiflora) and raspberry (Rubus sp.) during the nesting periods (late May to early July) of 1983-1985, 1987-1988. In 1985, 1987 and 1988, active nests were marked and left in the field until nesting was completed (estimated from observations of other nests opened during that nesting period). Nests were collected in the early evening so that the resident female, assumed to be the mother, could be associated with her nest. Nests were split open lengthwise in the lab and the nest contents removed. The immatures were reared as described in Johnson (1988). The mother was weighed (live) using a Mettler analytical balance (?0.001 g). The mother and her offspring were preserved together in alcohol. In all, 20 completed nests (1 from 1985, 10 from 1987 and 9 from 1988) were collected with their mothers. A nest was considered complete if the egg in the outermost brood cell (the last one produced) had hatched and was a feeding larva. This means that it was at least 5 days since the last brood cell was provisioned.

Variables affecting capture of stored-grain insects in probe traps.

Abstract: Many variables affect probe trap catch of stored-product insects in bulk grain. Often these variables affect trap catch because of their influence on behavior and mobility of insects. Five of the most important variables affecting trap catch are insect species, trapping duration, grain temperature, grain type and condition, and trap placement. The number of Cryptolestes ferrugineus (Stephens), Rhyzopertha dominica F., Tribolium cas taneum (Herbst) and Sitophilus oryzae (L.) captured per trap increased by 0.77, 0.26, 0.36 and 0.47 insect, respectively, per day of trapping. Temperature significantly affected only the number of C. ferrugineus caught and captures per trap increased by 0.35 insect per degree between 10 and 32?C. Captures of Cryptolestes pusillus (Schonherr) in millet were 2-3 times greater than in wheat or corn. Aggregated distributions of insects make trap catch very sensitive to trap placement. Estimates of insect populations in stored grain using probe traps are likely to be inaccurate without careful consideration of these factors. Sampling is a critical component of any management program for stored-prod uct insects. The use of traps to sample stored-grain beetles has been studied extensively during the past 2-3 decades (Loschiavo and Atkinson, 1967, 1973; Lippert and Hagstrum, 1987; Fargo et al., 1989; Subramanyam and Harein, 1990). Insect traps are effective and sensitive tools for detection of adult insects (Los chiavo, 1974, 1975; Barak and Harein, 1982; Lippert and Hagstrum, 1987). They capture more insects than a grain sample taken using a standard grain sampling probe because the traps are left in the grain and capture insects over a period of time. The ratio of mean numbers of adult Rhyzopertha dominica F., Tribolium castaneum (Herbst), Oryzaephilius surinamensis (L.), and Cryptolestes ferrugineus (Stephens) trapped to the mean numbers in grain samples varied from 2.87:1 to 6.75:1 after 5 days of trapping in shelled corn (Barak and Harein, 1982) and 1.7: 1.0 to 2.6:1.0 after 2 days of trapping in wheat (Lippert and Hagstrum, 1987). These studies suggest that traps may be useful in estimating densities of stored grain insect populations. All insect traps depend on insect movement. Any factor that influences insect movement will also affect trap capture. The magnitude of this effect depends primarily on insect species, temperature, grain type and grain condition. For rel ative population estimates, these factors can be incorporated into action threshold tables to assist stored-grain managers in interpreting trap catch and to make economically sound decisions (Higgins and Lippert, 1988; Cuperus et al., 1989). When samples are taken without monitoring these factors, there will be no way to remove the variability in trap catch, and estimates are likely to be inaccurate (Wright and Mills, 1984; Lippert and Hagstrum, 1987; Fargo et al., 1989; Subra manyam and Harein, 1990). These studies of probe traps are used here to illustrate 1 USDA, ARS, U.S. Grain Marketing Research Laboratory, 1515 College Ave., Manhattan, Kansas 66502. Accepted for publication 15 July 1990. This content downloaded from 207.46.13.113 on Thu, 06 Oct 2016 04:08:38 UTC All use subject to http://about.jstor.org/terms VOLUME 63, NUMBER 4 487 the importance of insect species, trap placement, grain temperature, trapping duration, grain type and grain condition in interpreting trap catch. BEHAVIOR OF SPECIES IN RELATION TO TRAP PLACEMENT! T. Castaneum and C. ferrugineus both are very active insects, whereas R. dominica does not move as much as other species and therefore is not as likely to be trapped (Subramanyam and Harein, 1989). This also results in differences in the distribution of insects within the grain mass and thus influences trap catch. The majority of stored-grain insects have aggregated distributions within the grain mass. Thus, the variability in insect numbers between two grain samples from the same location is as great as between different quadrants of a grain bin, or between grain bins (Hagstrum et al., 1985). Subramanyam and Harein (1990) obtained similar results with traps. Surtees (1965) suggests that stored-grain insects move randomly until a suitable location is found and that a population never becomes totally inactive. Variation in temperature and moisture within a grain mass (Hagstrum, 1987) results in some areas being more favorable for insects than others. C. ferrugineus movement is affected by moisture, temperature and gravity (Loschiavo, 1983; Watters, 1969). Legg et al. (1987) indicated that the aggregation of maize weevil, Sitophilus zeamais Motschulsky, was directly related to initial population density. The behavior of the insects colonizing the surface of grain and dispersing into the grain mass also contributes to the aggregated distributions (Hagstrum, 1989). These aggregated distributions make trap catch very sensitive to trap placement. Species-specific distribution has received rela tively little attention and is a critical issue that must be addressed if effective sampling programs are to be developed and implemented. Without knowledge of how different insect species distribute themselves in grain, a high sampling in tensity is needed to compensate for aggregated distributions. grain temperature: Several authors have found that trap catch was signifi cantly greater at higher grain temperatures (Loschiavo and Smith, 1986; White and Loschiavo, 1986; Fargo et al., 1989). In these studies, capture rate of Cryp tolestes spp. increased significantly at higher temperatures. However, between 10 and 32?C, other species including R. dominica, T. castaneum, and S. oryzae were not captured in greater numbers at higher temperatures (Table 1). trapping duration: Fargo et al. (1989) showed that the number of insects of a given species trapped increased significantly (P < 0.05) with trapping duration (Table 1). These slopes indicate that the response to trapping duration varies with species, and thus should be considered when interpreting trap catch. Choice of trapping duration can be complicated by the fact that trapping efficiency changes due to insects already trapped emitting an aggregation or sex pheromone thus increasing trap attractiveness over time (Loschiavo, 1974; Barak and Harein, 1982). However, data from Fargo et al. (1989) do not support this hypothesis. grain type and condition: Grain type has been shown to have an impact on trap catch for known densities of insects. Wright and Mills (1984) showed that catches of Cryptolestes pusillus (Schonherr) in millet were 2-3 times greater than in wheat or corn. The amount of cracked grain and fine material also influences insect movement. McGregor (1964) reported that T. castaneum were attracted to areas in the grain that contained higher concentrations of fine material. Watters (1969) showed that moisture and fungi can also affect locomotor activity of insects. The condition of the grain may also have an impact on the random movement of the insects and thus affect the number of insects trapped. This content downloaded from 207.46.13.113 on Thu, 06 Oct 2016 04:08:38 UTC All use subject to http://about.jstor.org/terms 488 JOURNAL OF THE KANSAS ENTOMOLOGICAL SOCIETY Table 1. Regression models for effect of temperature or trapping duration (x) on mean trap catch (y) for four species of stored-grain insects.3 Species N* Slopec SE Intercept0 SE r2 Temperature C. ferrugineus 12 0.3491** 0.0596 -1.2792 1.3685 0.77 R. dominica 12 0.0067 0.0106 0.1742 0.2438 0.04 T. castaneum 14 0.0225 0.0432 1.1678 0.9805 0.02 S. oryzae 14 0.0563 0.0528 0.7268 1.1991 0.09 Duration C. ferrugineus 8 0.7746** 0.1469 0.7738 0.6144 0.82 R. dominica 8 0.2643* 0.1065 0.0500 0.4458 0.51 T. castaneum 8 0.3551* 0.1247 1.3611 0.5218 0.57 S. oryzae 8 0.4714** 0.1169 0.2000 0.4892 0.73 a Reanalyzed data from Fargo et al. (1989). These studies were done with 40 adults in 1 bu lots of wheat. b Means based on catches from five to seven traps. c Slopes or intercepts are significantly different from zero at the 1% or 5% level if followed by ** or *, respectively. summary: Insect species, trap placement, grain temperature, trapping duration, grain type and grain condition greatly influence trap catch. Estimates of absolute insect populations from trap catch will be inaccurate unless adjustments are made for these factors. With adequate understanding of variables that affect trap catch, multiple regression analysis can be used to estimate absolute populations (Lippert and Hagstrum, 1987; Southwood, 1978). Regression equations in Table 1 for capture rate as a function of trapping duration and temperature should be ex tremely useful for adjusting trap catches obtained with different trapping durations or from bins with differing temperatures. To improve reliability and utility, further research is needed on the number of traps required, placement of traps, the role of attractants and interpretation of the importance of various factors relative to trap catch.

Survival of Rhyzopertha dominica (Coleoptera, Bostrichidae) on fruits and seeds collected from woodrat nests in Kansas.

Abstract: In the laboratory, cache materials from eastern woodrat nests were inoculated with lesser grain borer (Rhyzopertha dominica) adults and incubated for 3 months to observe survival and reproduction Adults survived for more than 1 month on fruits of sandhill plum (Prunus angustifolia), chinkapin oak (Quercus muehlenbergii), hackberry (Celtis occidentalis), buckbrush (Symphoricarpus orbiculatus), and black walnut (Juglans nigra) Progeny were produced on acorns (husk damaged) and hackberry and buckbrush fruits Wild populations of lesser grain borer were not observed emerging from any of the cache materials The lesser grain borer, Rhyzopertha dominica (F), is a specialized grain-feeding member of the family Bostrichidae, a woodboring group of insects In recent studies on field biology in Kansas, adult beetles have been found flying in April and May at some distance from farm-stored grain (Wright, unpubl data) The lesser grain borer has been collected in pheromone traps in many diverse habitats (Cogburn, 1988) and has been observed tunneling in various types of wood (Potter, 1935; Mathew, 1987) Other stored-product insects have been found in bee and wasp nests, bird and rodent nests, and other habitats (Linsley, 1944) Information on lesser grain borer field biology is minimal We hypothesized that some sources of food or overwintering sites away from grains and animal feed may be present in the local habitat materials and methods: Several kinds of fruits and seeds were collected from eastern woodrat, Neotoma floridana, nests near Manhattan, Kansas, during the winter of 1988-1989 The nests were located in wooded habitat adjacent to fallow fields Other workers have found that small mammal caches are good sources of grains, seeds and fruits (Smith and Reichman, 1984) Caches of eastern woodrat removed from nests in December 1988 contained from 400 to 12,000 g of seeds, fruits and leaves (Wooster, pers comm) The cache materials were sorted by type and equilibrated in an environmental chamber at 28 ? 1?C and 65 ? 5% RH for 1 week Twenty adult lesser grain borers (10 ? 10 days old) were added to each type of cache material in a glass jar with a screened lid Each jar represented the total material from one woodrat nest with different quantities available per nest Approximately 1 month later, each jar was checked for live and dead adults, signs of damage and reproduction Any adults were removed when found Dust from insect damage (which might include eggs or small larvae) was returned to the jar along with the cache material for another month This procedure was repeated three times At the final observation, nuts and seed pods were dissected and adults found were included in the data for the third month results and discussion: Lesser grain borer adults were able to survive at least 1 month on five types of cache material (Table 1): fruits of sandhill plum (Prunus angustifolia Marsh), chinkapin oak (Quercus muehlenbergii Eugelm), hackberry (Celtis occidentalis L), buckbrush (Symphoricarpus or biculatus Moench) and fragrant sumac (Rhus arom?tica Ait) On dried plum fruits with pits, adults survived for more than 1 month but no progeny were found On plum pits only there was no survival Adults survived on fruit of fragrant sumac through the first month, but no reproduction was observed Chinkapin oak acorns (broken by woodrats) supported adults for 3 months No larvae were observed outside of the husks However, six new adults emerged in the second month Acorn meats were extensively tunneled and full of frass and dust (Fig 1) Other stored-grain insects have been reported to breed successfully in acorns (Joubert, 1966; Mills, 1989) Adult progeny emerged from hackberry (dried fruits with pits) in the second and third months The number differed from one batch of material to the next (Table 1) Fruits from different caches were of various maturities The less ripened fruits were not infested by lesser grain borer Mature fruits 1 Kansas Agricultural Experiment Station Contribution No 90-39-J Accepted for publication 23 October 1989 This content downloaded from 2074613120 on Wed, 14 Sep 2016 04:20:11 UTC All use subject to http://aboutjstororg/terms

Components of host choice by two Rhagoletis species (Diptera: Tephritidae) in Utah.

Abstract: Physical components of host choice were examined in two Rhagoletis species that have recently become pests of sour cherry (Prunus cerasus L.) in Utah: R. indifferens Curran, which is widespread on cherry and apparently has no native host, and R. pomonella (Walsh), which is widespread on native hawthorn and infrequently attacks cherry. When presented with artificial hosts, the two species responded similarly to host size but not to host color. Color preferences of R. indifferens females were orange > black > red, while those of R. pomonella females were red > orange > black. Size preferences were measured either as the frequency of attempted oviposition into different-sized spheres or as the number of eggs laid in different-sized wax domes. Results from the two kinds of assays were similar if egg densities in domes were expressed in terms of available surface area. Each fly species generally failed to discriminate between small (hawthorn-sized) and me dium (cherry-sized) artificial hosts, but strongly preferred medium hosts over large hosts. Size discrimination by R. indifferens females was independent of fly age. Fruit flies of the genus Rhagoletis use a variety of sensory modalities and host cues to locate suitable oviposition sites. Visual (Prokopy, 1968; Owens and Pro kopy, 1986) and olfactory (Averill et al., 1988, and references therein) stimuli are especially important in the sequential process of host selection. Understanding how flies react to specific host cues can be useful for predicting the susceptibility of potential host species or cultivars (Diehl and Prokopy, 1986; Carle et al., 1987), for designing appropriate traps (e.g., Frick et al., 1954; Riedl and Hislop, 1985; Drummond et al., 1984), and for developing a rearing program that requires egg laying in artificial hosts (Prokopy and Boiler, 1970; AliNiazee and Brown, 1977). In this study I compare responses to host cues by two Rhagoletis species that have recently become pests of sour cherry, Prunus cerasus L., in Utah. The western cherry fruit fly, R. indifferens Curran, is indigenous to the Pacific Northwest, where its native host is bitter cherry, Prunus emarginata (Dougl.) D. Dietr., and where it has attacked cultivated cherries for more than 75 years (Bush, 1966). This species was first reported in Utah in 1980 (Davis and Jones, 1986). Utah populations were found to attack sweet cherry, Prunus avium L., and sour cherry, but apparently have no native host. The apple maggot, R. pomonella (Walsh), is associated with the native black hawthorn, Crataegus douglasii Lindl., in Utah, but was also discovered in sour cherry in 1983 (Jorgensen et al., 1986). Fly populations in Utah represent the first instance that R. indifferens and R. pomonella co-occur in a host; the apple maggot occasionally has been reported to attack cherries elsewhere (Shervis et al., 1970), but never within the geographic range of R. indifferens. Extensive trapping in cherry orchards from 1985 to 1988 revealed that R. indifferens has quickly become a widespread and abundant pest of cherry in Utah. Accepted for publication 8 June 1989. This content downloaded from 157.55.39.108 on Fri, 17 Jun 2016 05:30:25 UTC All use subject to http://about.jstor.org/terms VOLUME 63, NUMBER 1 81 In contrast, R. pomonella, which is widespread in hawthorn, has infested cherry only within a limited area in central Utah (Spangler, 1986). Moreover, populations have been dwindling at most of these sites (Allred and Burgess, 1988). Biological differences between the two species, as well as cultural practices, may contribute to their differential success in cherry. Here I examine how females of each species respond to host size and color. Materials and Methods Flies used in the experiments were obtained from naturally infested fruits at two sites in Cache Co., Utah. Larvae of R. indifferens were collected from an abandoned sour-cherry orchard in Providence, while R. pomonella larvae were collected from a large stand of black hawthorn in Wellsville. Fruits were placed on screens over moist vermiculite, which provided a medium for pupation after larvae left the fruit. Puparia were sifted from the vermiculite, chilled at 6-8?C for 7-10 months, and incubated at 25?C and 16:8 (L:D) photoperiod. Emerging adult flies were placed in 30 x 30 x 30 cm cages of Plexiglas and organdy cloth. Flies were provided water and Bio-Serv Adult Apple Maggot Diet #9148 (Bio-Serv Inc., Frenchtown, NJ, after Boush et al., 1969, Diet C). Because prior experience is known to influence fly behavior (e.g., Papaj and Prokopy, 1986), flies used in the experiments had no exposure to natural or artificial fruits. Each species was tested 16-20 days after adult emergence. Previous experience indicated that most flies are ready to oviposit at 16 days following eclosi?n. A greater availability of R. indifferens females permitted the use of additional age classes (5-10, 11-15, and 21-25 days) in two experiments. Responses to host color were measured by providing flies with pairwise com binations of orange, red, or black wax domes. Hollow, hemispherical domes were constructed from soft ceresin wax (provided by E. F. Boiler, W?denswil, Swit zerland) using techniques similar to those described by Prokopy and Boiler (1970). Orange and black powdered dyes were obtained from Wernle AG, Z?rich (pro vided by E. F. Boiler), while red dye ('Holiday Red') was obtained from Walnut Hill Co., Bristol, Pennsylvania. Two trials were conducted for each pair of colors. In each trial, 12, 1.85 cm diameter domes of each color were placed in an alter nating 4x6 array on white depression plates, with 30 mm between the center of adjacent domes. White plates provided a high contrast between domes and background. Domes were placed on a platform near the top of a cage bearing ca. 50 female flies, and the number of eggs in each dome was recorded after 16-20 hr. Responses to host size were measured in two ways. In one assay, flies were presented different-sized red domes. Two size comparisons were tested: small (1.35 cm diameter) vs. medium (1.85 cm), and medium vs. large (4.25 cm). Three trials were conducted for each comparison. In each trial, eight domes (four domes of each type) were arranged in an alternating 2x4 array, with 5 cm between the center of adjacent domes. Presentation of different-sized domes was otherwise similar to the presentation of differently colored domes, and the number of eggs was again recorded after 16-20 hr. A second assay measured the propensity to oviposit into spheres of different sizes. Wooden spheres were spray-painted with red, acrylic enamel paint (Custom Color F8X-1, Sherwin-Williams Acrylyd, Cleveland, OH) and dipped in ceresin This content downloaded from 157.55.39.108 on Fri, 17 Jun 2016 05:30:25 UTC All use subject to http://about.jstor.org/terms 82 JOURNAL OF THE KANSAS ENTOMOLOGICAL SOCIETY f?. indifferens R pomonella

Interpretation of trap catch for detection and estimation of stored-product insect populations.

Abstract: Methods available for interpretation of trap catches of stored-product insects are discussed. Trap efficiency must be determined to convert trap catches into absolute densities. Much of the variation in trap catch may be attributable to variation in trap efficiency in response to environmental factors rather than to actual changes in insect population density. Therefore, regression equations for calculating trap efficiency over a range of environmental conditions may be needed to convert the number of insects caught to absolute densities. Calculating the probability of detection or the accuracy of estimation insures that trap catches are not extrapolated beyond the limits of their resolution. Insect population dynamics models are useful in predicting future insect population densities from trap catches and in relating trap catches to developmental stages not trapped. Inter pretation of trap catch must begin with careful planning of a trapping program if these three methods of interpreting trap catch are to be fully utilized to provide correct conclusions in research programs and appropriate decisions in management programs. Traps exploit insect behavior to detect insect populations with less effort than more absolute sampling methods. However, this exploitation of behavior may result in large variations in trap catch. Much of this variation in trap catch may be attributable to variation in trap efficiency in response to environmental factors rather than to actual changes in population density. Trap efficiency is defined as the portion of total population per unit volume that is captured during a sampling period. We will consider here, methods available for interpretation of trap catches of stored-product insects in research studies or in pest management programs. Trap efficiency can be used to convert the number of insects caught to absolute insect density by dividing trap catch by trap efficiency. The resolution that is possible in the detection or estimation of insect density can be determined by calculating the number of traps needed based on changes in the probability of detection or the accuracy of estimation with insect density (Hagstrum et al., 1988). In some cases, density estimates for the stage captured (adults) can be used to estimate the densities of the other stages (larvae and pupae). This is often im portant when we are not trapping the stage causing economic losses. These esti mates of population density can also be entered into population growth models to predict future changes in insect population densities. Careful planning of a trapping program is the first step to fully utilize these techniques and to better interpret trap catch. Even the best statistical analyses cannot compensate for 1 Department of Entomology, University of Minnesota, St. Paul, Minnesota 55108. 2 Crops Research Laboratory, Agricultural Research Service, U.S. Department of Agriculture, Hills boro Street Ext., Oxford, North Carolina 27565. 3 Department of Entomology, Oklahoma State University, Stillwater, Oklahoma 74078. Accepted for publication 15 July 1990. This content downloaded from 157.55.39.157 on Fri, 08 Jul 2016 05:21:00 UTC All use subject to http://about.jstor.org/terms VOLUME 63, NUMBER 4 501 deploying too few traps or not collecting data on environmental factors that affect trap efficiency. One of the first considerations in planning a trapping program is the estimation of trap efficiency so that the number of insects caught can be converted to absolute density of insects in or around stored commodities or a storage facility. Even detection implies some measure of population density in that lower densities are detected with increases in the number of traps, with longer trapping periods or with environmental conditions more favorable for insect activity. Management decisions based on detection alone assume that the probability of detection is directly related to insect density. Studies of adult stored-product insects have used a wide variety of methods for determining trap efficiency. Hagstrum and Stanley (1979) used the release-recapture method to estimate the percentage of the almond moths, Ephestia cautella (Walker), captured by suction traps in a peanut ware house. Over a broad range of insect densities from just a few to 400,000, six traps recovered an average of 7% of females and 20% of males during the first day after release. With a closely related pyralid moth, the Indianmeal moth, Plodia inter punctella (Hubner), at densities of 50 to 75 adults per 89 m3, Mankin et al. (1983) directly observed that 29.7% of males were captured by pheromone-baited sticky traps. However, only 61.7% of males observed approaching the traps were actually captured. In Australia, Sinclair and Haddrell (1985) used a truck trap to show that the densities of the lesser grain borer, Rhyzopertha dominica (F.), and the red flour beetle, Tribolium castaneum (Herbst), averaged 23 and 29 insects per mm3 of air, respectively, in an area where unbaited sticky traps caught an average of only 0.6 R. dominica and 0.7 T. castaneum per trap. The truck trap was a fine mesh funnel tapering from 1.5 x 0.6 m at mouth to a 25 cm diameter collecting bag. It is mounted on top of a truck and the volume of air sampled for insects is calculated from the distance the truck is driven. For a warehouse population of R. dominica, Leos-Martinez et al. (1986) found a good correlation between the catch per hour for two pheromone-baited Lindgren funnel traps and estimates of the number of adults per 985.6 m3 of air made using a calibrated Johnson-Taylor suction trap. With regression analysis, Leos-Martinez et al. (1986) found that estimated adult densities per volume of air explained 67 and 88% of the variation among pheromone-baited Lindgren funnel traps. In farm-stored wheat, Lippert and Hagstrum (1987) found that the average densities of adult rusty grain beetles, Cryptolestes ferrugineus (Stephens), caught in probe traps averaged from 1 to 17 as the average densities of C. ferrugineus in a 0.265-kg grain sample increased from 0.2 to 1.8 adults. With regression analysis, Lippert and Hagstrum (1987) found that estimated trap efficiency explained 37% of the variation among probe traps. With a density of 40 adults per 27.2 kg-lots of wheat in the laboratory, Fargo et al. (1989) demonstrated with probe traps that the catch of four species, R. dominica, T. castaneum, C. ferrugineus and rice weevil, Sitophilus oryzae (L.), varied from 1 to 25% over a 10 to 32?C temperature range. At 23?C, from 1 to 14% of the insects were captured as the duration of trapping increased from 1 to 7 days. White and Loschiavo (1986) also reported differences in the percentage of populations of T. castaneum and C. ferrugineus captured with probe traps in two temperature ranges. Wright and Mills (1984) reported differences in the per centage of flat grain beetles, Cryptolestes pusillus (Schonherr), captured with probe traps in maize, wheat, sorghum and millet. This content downloaded from 157.55.39.157 on Fri, 08 Jul 2016 05:21:00 UTC All use subject to http://about.jstor.org/terms 502 JOURNAL OF THE KANSAS ENTOMOLOGICAL SOCIETY Fig. 1. Variation in the probability of detection with the number of traps and insect density based on equation from Hagstrum et al. 1988. If we are to routinely use these estimates of trap efficiency to convert trap catches to absolute density in trapping programs, we will need to consider the most important factors influencing trap catch over a broad range of conditions, and possible interactions among these factors, using regression analysis. In an ideal calibration study, multiple regression is used with absolute density as the dependent variable, and trap catch and environmental factors as the independent variables. Only environmental factors that explain a high percentage of the vari ation should be included in the final regression equation used to convert trap catches to an absolute density. Another step in planning a trapping program is to calculate the minimum number of traps needed to detect the lowest density of insects that is of interest, or to estimate densities of insects with the desired accuracy. Such calculations are generally based on fewer samples being required for uniformly distributed pop ulations than aggregated populations, because the variation among traps in the number of insects captured decreases as the distribution of the population becomes more uniform. Hagstrum et al. (1988) demonstrated that the distribution of insects among samples was similar for several species of stored-product insects in a number of diverse situations. Thus, the calculated minimum numer of samples would be the same. This similarity suggests that the results of this study may be generally useful in providing an initial estimate of the minimum number of traps needed in a new trapping program. Figure 1 shows the typical increase in the This content downloaded from 157.55.39.157 on Fri, 08 Jul 2016 05:21:00 UTC All use subject to http://about.jstor.org/terms VOLUME 63, NUMBER 4 503 6.00 -q-1-1-1-1-1-1-1 % 5.00 4-1? CD = g 4.00^ O 3.00^-'-~? l_ mwmm -g 2.00 -z-j-HB-r-^^ i loo -f-----.-.=~ bh9?.-.-. MMMMI o.oo -^-1-1-1-"-j-1-'-j-1-' 555555555

Pollen harvesting rates for Apis mellifera L. on Gossypium (Malvaceae) flowers.

Abstract: Pollen harvesting rates were determined for honey bee foragers on flowers of Gossypium thurberi. Foragers visited 2.2-4.8 flowers/minute and collected 0.5-1.0 mg of pollen per minute. Pollen grains are 103-128 \im in diam., moist and sticky, allowing the collection of 894-1778 grains/minute. Pollen collection time was not significantly different for bees that collected only pollen (0.9 ? 0.1, SD, mg/minute) compared to nectar foragers (0.8 ?0.2 mg/minute) that passively acquired, then packed pollen. These are apparently the first empirically derived pollen-collecting rates for A. mellifera on any angiosperm. Pollen collection in relation to floral morphological complexity and hidden pollen is also discussed. Differences in foraging efficiency of bees gathering nectar and/or pollen are readily apparent. Nectar foraging rates for honey bees and other social bees on various plant species and floral types have been quantified frequently (see table 10.1 on page 173 in Winston, 1987, and references therein). This is probably because nectar is relatively easy to quantify within flowers and bees, and the standing crop of nectar within floral patches can be readily estimated. In contrast to the situation with nectar, there are few quantitative data on pollen collection ("harvesting" rates) for Apis mellifera (Park, 1922, 1928; Ribbands, 1953; Win ston, 1987) and other bee species. Such data are important because pollen is the primary proteinaceous and lipoidal food of most bees. Pollen usually consists of discrete particles of 5-200 Aim, rarely as large as 300 ?m (Roberts and Vallespir, 1978; Buchmann, unpubl.). This variability increases the difficulty of rapidly assessing the weight or number of pollen grains within flowers in the field using simple and inexpensive equipment. However, honey bees or other species that have acquired nearly full pollen loads are easily captured to permit the quantification of their respective pollen loads. Within the vast apicultural literature, there is almost no available data on the rate at which honey bees visit flowers, and particularly scant data on their handling times for pollen extraction from various flowers. Previous anecdotal qualitative estimates for pollen harvesting rates are found in the apicultural literature (Gillette, 1897; Jay, 1986; Maurizio, 1953; Park, 1922, 1928; Ribbands, 1949; Percival, 1947; Singh, 1950; Weaver et al., 1953), but this information is not especially useful for demonstrating how fast honey bees collect pollen under diverse me teorological conditions, or from a variety of specialized floral structures. Fur thermore, we have no quantitative measures of the time required for a naive forager to discover the most efficient ways to harvest pollen nor how learning 1 Mention of a proprietary product or trademark does not constitute endorsement or recommen dation by the USDA-ARS for its use over any other product. Accepted for publication 8 June 1989. This content downloaded from 157.55.39.104 on Mon, 20 Jun 2016 06:36:48 UTC All use subject to http://about.jstor.org/terms VOLUME 63, NUMBER 1 93 may decrease foraging rates. Our objective was to determine pollen harvesting rates for experienced honey bee foragers visiting simple open (haplomorphic) flowers that contained pollen and nectar. Furthermore, we present field and lab oratory methods that can be modified for a variety of bee species foraging to define pollen collecting rates on many diverse floral morphologies. Materials and Methods TECHNIQUE FOR OBSERVING AND COLLECTING HONEY BEES! Foragers from tWO to five managed colonies of honey bees of European stock (A. m. ligustica L.) located on the grounds of the Carl Hayden Bee Research Center in Tucson, Arizona were observed. Bees from these colonies located and visited three large cultivated plants of Gossypium thurberi within 100 m of the experimental apiary. A small number of marked foragers (10-20) from these colonies made daily visits to three of these large (4 m wide by 3 m tall) G. thurberi plants from mid-September to October 20, 1987. Bees were active on these plants from 0745 until 1100 hours MST at the end of which time there was little intrafloral pollen remaining. Each morning from October 5-7, 1987 at 0800 MST, the time when cotton flowers were at anthesis, newly arrived bees were visually inspected to determine if any corbicular-resident or loose pollen grains were present. Bees contaminated with more than a few dozen pollen grains (individual grains are easy to see due to their large size) were rejected and other bees observed. When a "clean" bee was found, an observer timed and followed the bee from an unobtrusive distance of 1-2 meters. Interfloral flight behavior was documented by recording number of flowers visited and whether the bee was collecting only pollen or was passively acquiring pollen as a normal byproduct of nectar feeding. We realize that no pollen is ever "passively" acquired, but simply collected by another behavior. A "floral visit" was defined as a bee landing on a flower and harvesting pollen. A floral visit was scored when a bee left one flower, hovered, groomed/packed pollen then returned to the same flower. Bees, marked individuals, usually visited the same flower only once during a foraging bout, thus floral visits almost always equalled the total number of flowers visited during a bout. Pollen loads increased rapidly on bees and usually after several minutes (2-10) timing was stopped and the bee carefully netted and killed in a vial of 95% ethanol. Collection rates were uniform through out the pollen harvesting process. Seven or eight bees were followed and captured in a period of 1-2 hours each morning on 6 days while flowers were fresh and pollen standing crops were high. Field data collection was terminated after a total of 20 foragers were collected in the above manner. LABORATORY COUNTING OF POLLEN GRAINS ON HONEY BEES! Snap-Cap Style polyethylene vials containing bees and 10 ml 95% ethanol were individually processed by submerging 1-2 cm of a Sonicator micro-tip (Ultrasonics Inc. model W-220F) into each vial for 15 seconds at a power setting of "5." This setting was previously determined to dislodge nearly all of the pollen from bees without also removing bee setae, wing fragments or other debris. The sonicator tip was washed into the resident vial, which was capped until pollen counting occurred. Pollen grain equatorial diameters were determined microscopically at 400 x magnifi cation using an ocular micrometer. Fifty pollen grains were measured yielding a mean and range which was then used to set the size "windows" on the particle This content downloaded from 157.55.39.104 on Mon, 20 Jun 2016 06:36:48 UTC All use subject to http://about.jstor.org/terms 94 JOURNAL OF THE KANSAS ENTOMOLOGICAL SOCIETY

A mixed colony of eulaema hymenoptera apidae natural enemies and limits to sociality

Abstract: In a natural mixed colony of 12 Eulaema polychroma and three E. cingulata all female bees foraged from first sunlight to dusk and possessed fully developed ovarioles. The hypogeous nest was separated by more than a meter from the entrance and was not discovered, but bees of both species at least shared a common nest entrance and a single long entrance tunnel. From a nest of Eulaema meriana five female mutillids, Hoplomutilla xanthocerata, and three female euglossine cleptoparasites, Exaeretefrontalis, emerged from 11 cells. The parasites did not interact aggressively and mutillids did not open cells of Eulaema despite confinement in a nest box for 2 months. Emergence holes of parasites indicated that from 33 cells of E. meriana, 5 Exaerete and 11 Hoplomutilla emerged. No emergence occurred from six cells containing mold, three of them parasitized by Hoplo mutilla. This nest and one reported in a previous study had 75-76% parasitism, each in natural forest habitat. High rates of parasitism may promote sociality in euglossines, but the complete lack of relatedness in the mixed colony of Eulaema suggests that tolerance of non-kin discourages kin selection and the evolution of eusociality. Sustained mixed colonies in the Apidae have been recorded only once in natural conditions, between two species of Melipona (Roubik, 1981). Temporary existence of more than one species in a nest is common in the bumble bees, shown by interspecific nest usurpation among Bombus and between host Bombus and para sitic Psythirus (Sakagami, 1976; Fisher, 1987). This type of association had never been noted within the uniquely neotropical apid group, the euglossines. It was therefore surprising to observe more than one species of Eulaema enter a nest in the ground in Panama. In addition, although various nest parasites are associated with euglossines (Dodson, 1966; Zucchi et al., 1969), I collected only parasites from the complete nest of another Eulaema located in a tree cavity. Whereas such field data on Eulaema are incomplete, they help to establish some factors that may have promoted the parasocial or temporarily eusocial life cycles thus far known among the euglossines (Gar?falo, 1985; Eberhard, 1988). Parasites or other natural enemies can be viewed as agents that encourage sociality, promoting guarding behavior and refinements in collective nest construction and mainte nance (Michener, 1985; Eickwort, 1986; Roubik, 1989). In this paper I suggest that some advantages of colony establishment can counter the evolution of eu sociality. New information on natural enemies and aspects of nesting biology of Eulaema are reported here to further our understanding of their social life cycles. Methods and Materials During late rainy season of 1988, on 6 September, I found cells of a large Eulaema in a rotten log that formerly held a colony of Tr?gona (Paratrigona) ornaticeps Schwarz (Roubik, 1983). This xylophilous colony had been kept in a shelter within the forest of Soberan?a National Park on the "Pipeline Road", 10 km N of Gamboa, Panama Province at an elevation of 100 m above sea level. 1 Mailing address: APO, Miami, Florida 34002-0011, USA. Accepted for publication 4 October 1989. This content downloaded from 207.46.13.101 on Sat, 08 Oct 2016 05:39:51 UTC All use subject to http://about.jstor.org/terms VOLUME 63, NUMBER 1 151 The tree cavity was cylindrical and 11 cm wide. At the time the nest was found, one female Hoplomutilla xanthocerata (Smith) was in the nest. The log containing the nest was in deep shade 1.5 m above the ground, positioned on top of another log and under a roofed enclosure within primary forest. The clusters of cells were removed from the log and transported to Curundu, near Panama city, and placed in a glass-topped observation hive. Emergence of all insects from the nest was recorded, and observations were made at least once a day to note whether they interacted aggressively or attempted to open other cells within the nest. Honey water on moist cotton was provided as nourishment. At the beginning of the dry season, on 4 January 1989,1 found another nest of Eulaema in the ground within a pasture 100 m from the forest edge. This hy pogeous colony was in the Azuero Peninsula, Los Santos Province 12 kw W of Tonosi, in the Gu?nico Valley at 560 m elevation. The first bee seen entering the nest at 1720 was a female Eulaema cingulata (Fabric?is), and then at 1740 two females of Eulaema polychroma (Mocs?ry) entered the same nest. The following day I recorded foraging activity by both species at its beginning and ending (0600 to 0900 and 1600 to 1800). At initiation of forager activity on 6 January, all exiting bees were collected and the nesting site was excavated. The bees were preserved in Dietrich's solution. In the laboratory, ovarian development was scored for each female, as was the length of the sting apparatus, maximum head width across the compound eyes, and conditions of the wing edges and mandibles.

The planthopper genus Prokelisia (Homoptera: Delphacidae): morphology of female genitalia and copulatory behavior

Abstract: The female genitalia of the five species of the planthopper genus Prokelisia are described and illustrated and a key for identification is provided. Form of the valvifers of the 8th abdominal segment and shape and dentition of the median gonapophyses of the 9th abdominal segment are used to separate species. Copulation in two of the species is described. The Nearctic delphacid genus Prokelisia consists of five species distinguished by characteristics of the male genitalia and frons (Wilson, 1982). Females have been difficult to identify because some individuals are intermediate in critical diagnostic features of the frons and no genitalic features were found that distin guished them (Wilson, 1982; pers. obs.). Morphometric analysis offrons length and width proved useful in separating most females and nymphs of two species (Dennoetal., 1987). Prokelisia planthoppers have been the focus of extensive ecological research (summarized by Denno et al., 1987), with emphasis on two sibling species using the same host plant (Wilson, 1982; Denno et al., 1987). No other North American planthopper taxon has received more ecological attention. Recent studies of the acoustic signaling and copulatory behavior of the sibling species P. dolus Wilson and P. marginata (Van Duzee) (Heady, unpublished data) resulted in accurate species assignment of females and discovery of a diagnostic character of the female genitalia. Once a reliable feature of females was available females could be ac curately identified and examined for other genitalic characters. Female genitalic characters have not been used extensively in planthopper systematics. This is due to the apparent lack of distinguishing features in some taxa (e.g., Myndus\ Kramer, 1979), insufficient examination or availability of specimens that can be associated reliably with males, and the paucity of detailed morphological descriptions. Female genitalia and form of the pregenital sternite have been illustrated, but rarely described, for some issid, flatid, and nogodinid taxa (Doering, 1932, 1938; Doering and Shepherd, 1946; Kramer, 1976). Female genitalia have also been used in separating species of some delphacid taxa (e.g., Ossiannilsson, 1978) such as Nilaparvata (Okada, 1977): their morphology has been detailed by M?ller (1942) and Asche (1985). Useful characters include the structure of the valvifer of the 8th abdominal segment (=first valvifer or lateral lobe (Ossiannilsson, 1978)), the shape and dentition of the median gonapophyses of the 9th abdominal segment (=second v?lvula or saw (Ossiannilsson, 1978)), the shape of the lateral gonapophyses of the 9th abdominal segment (=third valvulae or saw case (Ossiannilsson, 1978)), and the shape of the genital scale or atrium plate (Ossiannilsson, 1978; Remane, pers. comm.).

Unsaturated extracted hydrocarbon caste differences between European queen and worker honey bees, Apis mellifera L. (Hymenoptera: Apidae).

Abstract: Extraction and analysis of the hydrocarbons from European honey bee queens indicates the presence of unsaturated compounds not exhibited by worker bees. Queen specific hydrocarbons consist of a homologous series of long-chain alkenes sharing the common feature of being unsaturated 15 carbons from the end of the molecule (N-15 olefins) and two series of alkadienes. Extraction of specific body parts shows the queen specific hydrocarbons to be localized on the abdomen and concentrated on the dorsal surface, while the worker compounds are evenly distributed over the insect. Comparison of the average queen olefin abundance profile with the average profile for workers suggests that queens display additional biosynthetic paths which are masked in workers, and un

Pre-Africanized Apis mellifera (Hymenoptera: Apidae) swarming dynamics in northeastern Mexico and southern Texas.

Abstract: Two transects of clustered, pulp-pot style bait-hives were established in early 1988 to document, in advance of the northward dispersal of the Africanized honey bee, swarming activity and other characteristics of existing Apis mellifera populations in the northeastern Mexican state of Tamaulipas (63 monitoring sites; 252 traps) and in the Rio Grande Valley of southern Texas (36 sites; 144 traps). This represents the first such long term study of subtropical European honey bee swarming dynamics in the Americas. Swarm ing activity has been present during all months of the ongoing study (March to October) and has been bimodal with highest swarming levels from March to May and September to October. Slightly earlier swarming was observed on the Mexican transect. During the first 8 months of study reported here we captured a total of 277 swarms from the Mexican and 164 from the Texas transect. Swarming intensities during the peak swarming season were high enough to saturate trap clusters at many monitoring sites. Clusters of bait hives thus may be warranted during peak swarming seasons. Swarming activity on the physio graphically variable Mexican transect showed strong negative altitudinal/vegetational as sociations not seen on the more homogeneous Texas transect. It is suggested that such strong habitat-related correlations may prove important in bait-hive monitoring or control programs over wide geographic areas. The introduction of honey bees (Apis mellifera) of European ancestry to the Americas produced a unique ecological situation by allowing a 'founder' popu lation to expand and adapt, unhindered by tropical races, through the Americas for several hundred years. Since its arrival, it successfully occupied many habitats in temperate, subtropical, and to a lesser extent (Winston et al., 1983), tropical sections of both North and South America. An important entomological saga began 3 decades ago with the introduction to South America of a tropically adapted race of A. mellifera from South Africa (Kerr, 1967) and its now well published, but imperfectly understood, consequences (Winston et al., 1983; Rinderer, 1986; Taylor, 1985). With the advent of Africanization of the European honey bee populations of NE Mexico and southern Texas the question arises of what dif ferences exist between them and their arriving African conspecifics in their adopted American habitats. While we do understand a great deal about the biology and ecology of European A. mellifera, most of our knowledge of these races comes from studies done in temperate habitats. Studies from subtropical or tropical climates are few in com parison. Many of these studies have been done in the very recent past during the Africanization process. No long-term studies exist to allow comparisons of certain basic biological tenets, preand post-Africanization. Our ability to cope with the Africanization of existing populations lies in part in understanding the changes that occur upon their Africanization. It is therefore essential to have baseline 1 U.S.D.A., A.R.S., Honey Bee Research Unit, 2413 E. Hwy 83, Weslaco, Texas 78596. 2 Secretar?a de Agricultura y Recursos Hidr?ulicos, Programa Nacional para el Control de la Abeja Africana, 19 Guti?rrez y Lara, Ciudad Victoria, Tamaulipas, M?xico. Accepted for publication Sept. 21, 1989. This content downloaded from 207.46.13.71 on Sat, 22 Oct 2016 06:18:21 UTC All use subject to http://about.jstor.org/terms VOLUME 63, NUMBER 2 289 information on established European honey bee populations in non-temperate (subtropical and tropical) regions. One of the areas of interest in the comparative biology of extant European and impending Africanized populations lies in the large differences in their reproduc tive biologies, reflected by their highly distinctive swarming behaviors (Winston, 1980a; Winston et al., 1983). In temperate climates European swarms and after swarms issue primarily in the spring, usually in May or June, but there may be some secondary swarming activity in late summer (Simpson, 1959; Burgett and Morse, 1974; Fell et al., 1977; Winston, 1987). Some variability is apparent between different climatic regions both from year to year as well as among wide spread locations. In Manitoba, Canada and Wiltshire, England, the northernmost latitudes for which data are available, swarming activity is restricted to a short 2 to 3 month period (Jeffree, 1951; Mitchener, 1948). At a more southern latitude in Maryland the swarming season is prolonged somewhat, and a few swarms issue in fall months (Caron, 1979). Winston (1980b) also reports a longer swarming season in Kansas. Apparently an ethocline of swarming activity exists, but data on European bees in warmer climates are unavailable. In an effort to fill in the gap in our knowledge of likely soon-to-disappear subtropical populations of European honey bees in the Americas, we have been conducting studies of the extant honey bee populations in southern Texas and in central Tamaulipas State, Mexico since early 1988. Our goals are to gather as much information as possible on existing populations of honey bees before they become Africanized (Rubink et al., 1988). This may be our last opportunity in the Americas to quantify long-term aspects of swarming biology of non-African ized, subtropical honey bee populations. It affords an excellent opportunity to glean further useful knowledge of the Africanization process. A major thrust of our studies has been the establishment of swarm monitoring transects to study the extant subtropical European honey bee populations of north eastern Mexico and southern Texas. We report here some of the initial, unex pected, observations from the first 8 months of ongoing study of honey bee swarming dynamics. Materials and Methods Two swarm monitoring trap lines (Fig. 1) are in operation. The Mexican transect (MT), established in late February 1988, extends 200 km from a point 20 km west of the city of Ciudad Victoria, Tamaulipas, eastward to the Gulf of Mexico. It lies approximately 250 km south of the Texas/Mexico border. It crosses the entire coastal corridor through which Africanization is expected to proceed most readily, and traverses a wide range of agricultural and natural habitats ranging from sea level to 1200 meters elevation in the Sierra Madre Oriental. A second Mexican transect was recently established but data are not included in the present report. The Texas transect (TT), established between February and April 1988, extends westward 110 km from the city of Brownsville, Texas, through the Rio Grande Valley, to a point 30 km west of McAUen, Texas. It traverses primarily agricultural lands but also includes monitoring stations in two nearby natural areas, the Santa Ana National Wildlife Refuge (NWR) and the Bentsen Rio Grande State Park (BSP). This content downloaded from 207.46.13.71 on Sat, 22 Oct 2016 06:18:21 UTC All use subject to http://about.jstor.org/terms 290 JOURNAL OF THE KANSAS ENTOMOLOGICAL SOCIETY

Rates of parasitism by Diaeretiella rapae (Hymenoptera: Braconidae) for cabbage aphids (Homoptera: Aphididae) in and outside of colonies: why do they differ?

Abstract: Estimates of parasitism in samples of the cabbage aphid, Brevicoryne brassicae (L.) by the braconid Diaeretiella rapae (Mclntosh) in a field population in Massachusetts on collards were 2.3-4.3 times greater for \"scattered\" aphids than for aphids in colonies (defined as five or more aphids in physical contact). Laboratory and field experiments were performed to see if aphids separated from colonies were subject to higher rates of successful parasitoid attack, or if parasitized aphids were more likely to become separated from colonies because of increased rates of movement over the plant. Parasitism levels of \"scat tered\" aphids on potted collard plants exposed for 3 days in a collard field were 2.3-3.2 times higher than parasitism levels for aphids in colonies on identical potted plants at the same location for the same period. In laboratory experiments, aphids in colonies subjected to parasitism showed more movement than controls at 1 hr and 4 days after parasitoid attack, but at 8 days after attack cumulative amounts of movement of aphids in colonies subject to parasitism and control colonies not subject to parasitism were equal. From these results we conclude that higher levels of parasitism in \"scattered\" cabbage aphids seen on field plants are likely the result of the combined effects of higher levels of successful parasite oviposition in aphids already outside of colonies and higher rates of movement of aphids away from colonies after colonies are attacked by parasitoids. A field study of the cabbage aphid, Brevicoryne brassicae (L.), was conducted in S. Deerfield, Massachusetts in 1987 to assess the level of aphid mortality caused by the parasitoid Diaeretiella rapae (Mclntosh). Cabbage aphids occurred on the host plant, collards (Brassicae oler?cea acephala var. Vates), as scattered indi viduals and in groups of various sizes from 2-50 or more. As part of a host/ parasitoid study which has been reported elsewhere (Lopez and Van Driesche, 1989) all aphids on sets of 30-50 randomly selected collard plants were collected at this site every 2-3 days and dissected to determine whether or not they were parasitized. Aphids in these collections were segregated in the field into two categories which reflected whether they were from colonies or not. The category of \"colonies\" was defined for sampling purposes in the original study as at least five aphids in physical contact. Most aphids not in colonies, under this definition, occurred as singles or pairs. Colonies typically consisted of 5-15 individuals. Rare ly, very large colonies were encountered, consisting of hundreds of aphids. Estimates of parasitism from samples of these two categories were found to differ markedly, with parasitism of aphids not in colonies being 2-4 times higher (Lopez and Van Driesche, 1989). This difference in parasitism may have resulted at least in part from the greater percentage of aphids in colonies that were in the first instar (30.5-43.9%) as compared to the percentage for aphids not in colonies Accepted for publication 4 October 1989. This content downloaded from 24.34.193.204 on Tue, 16 Mar 2021 17:47:55 UTC All use subject to https://about.jstor.org/terms VOLUME 63, NUMBER 1 159 (10.1-22.7%) (Lopez and Van Driesche, 1989). Density on a per plant basis, however, did not seem to be a possible explanation as both categories of aphids occurred on most sample plants and aphid collections were pooled across plants and dates prior to comparison between categories. To test if cabbage aphids not in colonies were inherently more likely to become parasitized independent of their instar or density per plant, a field test (Exp. 1) was conducted in 1987 in the same collard field as used in the study of Lopez and Van Driesche (1989). The goal of Exp. 1 was to determine if the fact of an aphid either being in or outside of a colony could account for the observed differences in levels of parasitism seen for these groups in samples taken from the field population. Because parasitism can in some cases affect host behaviors such as movement, i.e. of the potato aphid, Macrosiphum euphorbiae (Thomas), induced by dia pausing Aphidius nigripes Ashmead (Brodeur and McNeil, 1989), a laboratory test (Exp. 2) was also run to determine if the higher level of parasitism of aphids not in colonies on field plants might have arisen from selective movement of aphids away from colonies after they had become parasitized. Materials and Methods experiment 1 : Collard plants 30-40 cm tall of the same variety (Vates) as used in the field plot at S. Deerfield, Massachusetts, were grown in pots in a greenhouse and were then infested with unparasitized cabbage aphids from a laboratory aphid colony maintained on the same variety of potted collards. Adult aphids were placed inside 9 cm2 leaf cages which were then clipped to the undersides of collard leaves. Leaf cages were constructed of disposable plastic petri dishes ventilated top and botton with fine netting and held in place by wooden clips. Twenty adult aphids were placed in each leaf cage and one cage was placed on each of five leaves per plant for 2 days in a greenhouse. Resultant colonies averaged 132 aphids, for an average per plant density of 660 aphids. Colonies were restricted to 9 cm2 areas until cages were removed. Twenty plants were infested in this manner and taken to a collard field at S. Deerfield, Massachusetts which consisted of 1000 plants, arranged in 20 rows, with 120 cm inter-row and 60 cm inter-plant spacing. Cabbage aphid densities in the field at the time plants for Exp. 1 were present averaged six aphids per leaf for the initial test (Trial 1) and eight aphids per leaf for a subsequent test (Trial 2). Of these, 13-24% were estimated by assessment of host and parasitoid recruitment to have been parasitized by Dia eretiella rapae (Lopez and Van Driesche, 1989). No other primary parasitoids of cabbage aphid were observed in the field. Immediately prior to placing infested potted collard plants in the field they were randomly divided into two groups of 10 each. All aphid colonies on plants of one group (hereafter termed as the \"scattered\" treatment) were proded with a fine tipped brush such that aphids moved away from colonies and became more widely dispersed over each of the originally infested leaves in smaller groups of various sizes. Aphids on the 10 plants in the other group (hereafter termed the \"in colonies\" treatment) were not disturbed in this manner and remained together in large colonies, averaging 132 aphids/colony, with one colony on each of five infested leaves per plant. Plants of both groups were then placed randomly in the collard field and left for 3 days (22-25 August 1987 for Trial 1). During this This content downloaded from 24.34.193.204 on Tue, 16 Mar 2021 17:47:55 UTC All use subject to https://about.jstor.org/terms 160 JOURNAL OF THE KANSAS ENTOMOLOGICAL SOCIETY exposure period, aphids were mostly second instars. Initial per plant aphid den sities were equal between treatments. At the end of the exposure period, plants were returned to the laboratory and placed for 2 days in an outdoor cage covered with fine screen capable of excluding parasitoids. Within the cage, plants of the cwo treatment groups were physically separated to prevent mixing of aphids. Post-exposure incubation was required to allow parasitoid eggs within aphids time to hatch, as the first instar parasitoid larva was the smallest stage of D. rapae that could be reliably detected by dis section. After incubation, all aphids from each plant were washed from leaves into alcohol and random samples of 30 aphids were selected for dissection from each plant. The level of parasitism for aphids on each plant in each treatment and the total number of aphids remaining on each plant after exposure and incubation were recorded. The experiment was repeated (Trial 2) 15-18 September 1987 in the same field in the same manner as for the first trial but plants bore fewer aphids (12-13 per infested leaf; 60-65 for whole plants). This infestation level more closely matched the colony sizes typically observed in the field population. These smaller colonies on plants in Trial 2 were obtained by reducing the number of adult aphids used per leaf cage during the infestation process in the greenhouse. When the same technique of using a brush to disturb aphids and make them leave their colonies was applied to 10 of the 20 plants used in the second trial, aphids on infested leaves became more thoroughly dispersed than was the case in Trial 1, with a higher proportion in Trial 2 occurring as singles or doubles. All aphids remaining on each plant at the end of the experiment were dissected to determine the level of parasitism. experiment 2: Cabbage aphid adults from the same greenhouse colony as used in Exp. 1 were also used for Exp. 2. Adult aphids were confined in leaf cages of the same design as described in Exp. 1, on the undersides of two leaves on each of three potted collard plants, 30-40 cm tall, for 1-2 days. Five to 10 adult females were placed in each cage, so that on each infested leaf one even-age group of 30 70 first instar nymphs was produced which was confined to a 9 cm2 area. The base of each infested leafs petiole was ringed with sticky material (Tac-Trap?) to prevent aphid movement off infested leaves. On each plant one leafs colony was designated as a control and the other as a treatment colony. One experienced D. rapae female, taken from a laboratory parasitoid colony maintained on cabbage aphids on potted collards, was then placed on the leaf of each plant bearing the treatment aphid colony and closely observed. The adult parasitoid, once its antennae had contacted one of the aphids in the colony, did not attempt to fly and could be directed from aphid to aphid with a fine brush, parasitizing one aphid after another. This procedure was followed, allowing one ovipositor insertion per aphid, until 50% of the aph

Bionomics of a Vernal Solitary Bee Andrena (Scrapteropsis) alleghaniensis Viereck in the Adirondacks of New York (Hymenoptera: Andrenidae)

Abstract: Information on the bionomics of a species of Scrapteropsis is presented for the first time. Unusual features include thermor?gulation by nest-site selection and facul tative oligolecty on Acer spicatum. Nests have only one or two cells, but some females make multiple nests. Details regarding habitat, host, nest structure, phenology, brood, and associates are provided. The Holarctic bee genus Andrena (Andrenidae) is one of the larger genera of animals (Sakagami and Matsumura, 1967). It includes about 700 Eurasian and 500 North American species, in 87 subgenera (Thorp, 1969; LaBerge, 1986). Not only are species numerous, but individuals of many of these species are seasonally dominant components of the total bee fauna in many parts of the world (Brittain and Newton, 1933; Atwood, 1934; Chambers, 1946; Hirashima, 1962; Knerer and Atwood, 1964). This genus of abundant bees has repeatedly been demon strated to be important for the pollination of major agricultural crops, as well as of wild plants. However, there has been surprisingly little investigation of the biology of Andrena species. Thorp (1969) estimated that the biologies of only 7 percent of all North American species have been studied. Except for floral records, no species of the subgenus Scrapteropsis has been investigated (LaBerge, 1971). Their brief period of adult activity during often unfavorable weather conditions, the cryptic nature of their nests, and their widely scattered aggregations of nests, render the study of Andrena bees difficult. The North American subgenus Scrapteropsis includes 18 vernal species (La Berge, 1971). The only reference to the nesting habits of this subgenus is a brief mention by Rau (1922) that A. {Scrapteropsis) imitatrix Cr. was "in its tunnel a few inches below the surface of the ground." Most members of this subgenus are vernal (Knerer and Atwood, 1964; LaBerge, 1971; Krombein et al., 1979). An drena alleghaniensis has been collected on a wide variety of flowers throughout its range (Knerer and Atwood, 1964; LaBerge, 1971; Small, 1976), but there is no indication in these floral records as to whether the bees were collecting pollen from these hosts, which would indicate the degree of polylecty. This species ranges from Saskatchewan and Maine south along the Appalachian Mountains to north western South Carolina, and in the Rocky Mountains to northern Utah and Colorado (LaBerge, 1971).