Showing papers in "Florida Entomologist in 2002"
TL;DR: There is considerable scope for improving the efficiency of medfly SIT, an indispensable requirement for increased involvement of the private sector in any future application.
Abstract: The Sterile Insect Technique (SIT) is amongst the most non-disruptive pest control methods. Unlike some other biologically-based methods it is species specific, does not release exotic agents into new environments and does not even introduce new genetic material into existing populations as the released organisms are not self-replicating. However, the SIT is only effective when integrated on an areawide basis, addressing the total population of the pest, irrespective of its distribution. There has been considerable progress in the development and integrated application of the SIT against the Mediterranean fruit fly (medfly), Ceratitis capitata, as reflected by operational programs for prevention, suppression and eradication of this pest. There is however, considerable scope for improving the efficiency of medfly SIT, an indispensable requirement for increased involvement of the private sector in any future application. One way to achieve this has been the development of genetic sexing strains, making it possible to release only sterile males. Another is improving sterile male performance through a better understanding of the sexual behavior of this insect. Unlike other insects for which the SIT has been successfully applied, medfly has a complex lek-based mating system in which the females exert the mate choice selecting among aggregated and displaying wild and sterile males. With the objective of developing a better understanding of medfly mating behavior, an FAO/IAEA Coordinated Research Project was carried out from 1994 to 1999. Some of the resulting work conducted during this period with the participation of research teams from ten countries is reported in this issue.
336 citations
285 citations
TL;DR: Seasonal abundance of the Asian citrus psyllid, Diaphorina citri Kuwayama, was studied weekly in two orange jasmine plots in southern Florida from October 1998 to October 1999 and general population trends on the two hosts were similar over time.
Abstract: Seasonal abundance of the Asian citrus psyllid, Diaphorina citri Kuwayama, was studied weekly in two orange jasmine [Murraya paniculata (L.) Jack] plots in southern Florida from October 1998 to October 1999. Psyllid populations occur throughout the season on orange jasmine in southern Florida. Population peaks were observed in October, November, and December in 1998, and May and August in 1999. Psyllid population levels were positively related to the availability of new shoot flushes which were in turn related to the weekly minimum temperature and rainfall. Natural enemies were not key factors in regulating populations during the study period. The populations of adult psyllids were also studied weekly on potted orange jasmine and grapefruit (Citrus paradisi Macfadyen) plants from June 1999 to July 2000. The population levels of psyllid on both host plants were not significantly different and general population trends on the two hosts were similar over time. Continuous shoot flushes produced by orange jasmine could play an important role in maintaining high populations of this insect when new shoot flushes were not available in the commercial citrus groves.
138 citations
TL;DR: This PCR-RFLP method does not require purification of mitochondrial DNA (mtDNA) or the use of radioactive isotopes, and differs from previous methods in that only a few nanograms of total DNA are needed to yield clear and accurate strain identification of individual insects.
Abstract: A simple method was developed to analyze the two morphologically indistinguishable host-associated strains of the fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith). Total DNA extracted from the FAW corn and rice strains, as well as from the S. frugiperda cell line (SF9) was used to PCR amplify a 569 base pairs region of the mitochondrial gene cytochrome oxidase subunit I (COI). The amplified DNA from the Spodoptera corn strain and the SF9 cell line contained a restriction fragment length polymorphism (RFLP) marker, the MspI recognition site that was not present in the rice strain. This PCR-RFLP method does not require purification of mitochondrial DNA (mtDNA) or the use of radioactive isotopes, and differs from previous methods in that only a few nanograms of total DNA are needed to yield clear and accurate strain identification of individual insects.
135 citations
TL;DR: Bimonthly inspections coupled with elimination of red ring diseased oil palms failed to reduce infection rates of oil palms in two commercial plantations in Costa Rica and addition of pheromone-based trapping of R. palmarum lowered RRD in both plantations by over 80% in one year.
Abstract: Rhynchophorus palmarum (L), the American palm weevil, is an important pest of several palm species in tropical America as a vector of the red ring nematode Bursaphelenchus cocophilus Cobb. Bimonthly inspections coupled with elimination of red ring diseased (RRD) oil palms (Elaeis guineensis Jacq.) failed to reduce infection rates of oil palms in two commercial plantations in Costa Rica. Addition of pheromone-based trapping of R. palmarum using trap densities of less than one trap per five hectares lowered RRD in both plantations by over 80% in one year. Continued removal of RRD infected palms and trapping maintained RRD at very low levels over several years. No matter what the initial RRD infection level, trap density or capture rate, areas with high and areas with low RRD infection levels declined to the same low RRD infection level after one year of trapping. An efficient strategy for management of RRD in oil palm is based on an integrated approach where RRD and other diseased (e.g., spear rot) palms are promptly eliminated or properly treated and pheromone-baited traps are used to reduce populations of R. palmarum. These strategies are complimented by removal of weevil-infested palms after wind and lightning damage and periodic removal of palms (e.g., coconut palms) in surrounding areas that serve as hosts for R. palmarum.
109 citations
TL;DR: The results revealed that the process of routine irradiation as commonly used in the mass rearing facilities at the time of the experiments, reduces the mating performance of the sterilized males nearly two-fold.
Abstract: The effects of routine irradiation of the mass-reared males of the medfly, Ceratitis capitata on their mating performance were re-evaluated. Male courtship behavior was observed and quantified both in laboratory (video recording cages) and field cage conditions. For the experiments, samples of the strains routinely mass-reared for SIT operations at Seibersdorf, Austria; Mendoza, Argentina and Metapa, Mexico, were used. No major qualitative differences were found in the courtship pattern between irradiated and non-irradiated males. However, the results revealed that the process of routine irradiation as commonly used in the mass rearing facilities at the time of the experiments, reduces the mating performance of the sterilized males nearly two-fold. A whole range of quantitative differences between the irradiated and non-irradiated males were detected and described, and their implications for the efficiency of SIT operations are discussed. In contrast, partial sterilization with low doses of radiation did not affect the mating competitiveness of the treated males to a noticeable degree. In view of the results obtained, and due to the current wider use of "male-only" strains in SIT operations, a re-evaluation of the sterilization strategy and irradiation doses for males used in SIT is recommended.
105 citations
90 citations
TL;DR: Differences in seasonal patterns and within plant distribution of Frankliniella occidentalis and tritici should be considered in developing sampling protocols and management plans for thrips.
Abstract: Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), the western flower thrips, is the primary insect pest of tomatoes and other vegetable crops in northern Florida and the rest of the southeastern USA. However, it is not the only flower thrips present in the region nor is it always the most abundant species. To determine the seasonal and within plant distribution of these various Frankliniella species, experimental tomato plants, grown under different nitrogen fertilization regimes, were sampled during the fall and spring growing seasons. Contrary to expectations, different levels of nitrogen fertilization did not affect the abundance of thrips species. Thrips were much more abundant in the spring than in the fall. In the spring F. occidentalis was the most abundant species, while in the fall F. tritici (Fitch) was the most abundant species. In both the fall and spring, significantly more adults occurred in flowers in the upper part of the plant canopy than in flowers in the lower part of the plant canopy. The sex ratio tended to be female biased, but with a greater percentage of males occurring in the upper canopy flowers. In contrast, significantly more immature thrips occurred in the lower part of the plant canopy than in flowers in the upper part of the plant canopy. Differences in seasonal patterns and within plant distribution should be considered in developing sampling protocols and management plans for thrips.
86 citations
TL;DR: It is shown that male diet significantly affects female receptivity: females whose first mate was protein-deprived, remate sooner than females whoseFirst mate wasprotein-fed.
Abstract: To realize their reproductive potential, male Mediterranean fruit flies must run a gauntlet of behavioral challenges during which they may be edged out by rivals, or fail the acid test of female choice. Milestones on this perilous road include: 1. showing up at a lek site, 2. emitting pheromone, 3. performing courtship, 4. copulation, 5. sperm transfer and storage, 6. fertilization of eggs, 7. preventing or delaying female remating. In a number of recent studies focused on each of these steps we tested the hypothesis that post-teneral male nutrition affects male sexual performance. Both field and laboratory data indicate that protein nutrition increases a male’s probability of emitting pheromone in a lek. Field cage data show that protein fed males are also more likely to engage in critical elements of close-range courtship, and evidence from several studies indicate that protein fed males are more likely to copulate than sugar-fed or starved flies. As to sperm transfer and storage, we find that ...
85 citations
TL;DR: In mating trials conducted on field-caged host plants, protein-fed males achieved significantly more matings than protein-deprived males, and these results are compared with other recent studies on the nutritional ecology of male Mediterranean fruit flies.
Abstract: Field experiments were performed to examine the effect of adult diet on calling activity, female attraction, and mating success in male Mediterranean fruit flies, Ceratitis capitata (Wiedemann). In all tests, comparisons were drawn between males fed sugar only (“protein-deprived” males) and males fed a protein-sugar mixture (“protein-fed” males). In tests of long-distance attraction, aggregations consisting of protein-deprived males exclusively or protein-fed males exclusively were established in a coffee field, and females were released from a central release point. Protein-fed and protein-deprived males displayed similar calling levels, but approximately twice as many female sightings were recorded at groups of protein-fed males than at groups of protein-deprived males. A second test of female attraction compared single groups of protein-deprived and protein-fed males within the canopy of a field-caged host plant. As before, calling activity did not vary with diet, and in this case numbers of f...
TL;DR: The use of various compounds to improve the mating success of mass reared males could have a major impact on the efficiency of SIT programs, however, the initial experiments reported here will need to be expanded before this approach can be integrated into operational programs.
Abstract: The preceding papers presented in this issue represent some of the activities of a group of researchers working on fruit fly mating behavior as it relates to the use of the Sterile Insect Technique (SIT). The group was co-ordinated and partially funded by the FAO/IAEA Joint Division of Nuclear Techniques in Food and Agriculture, Vienna Austria. A variety of approaches were used to examine lekking and courtship behavior of wild and mass-reared fruit flies including video analysis, morphometrics, physiological status, geographical variation and field cage evaluation. No major qualitative differences could be demonstrated between mass-reared males and wild males, although there were some specific changes related to mass rearing and irradiation. Many studies were carried out using field-caged host trees and the results of this work have led to the establishment of a standardized protocol that is now followed by all fruit fly programs using the SIT. Using these cage studies it was shown that there are no barriers to mating between medfly populations from many parts of the world. This information is of major relevance as it permits sterile flies to be shipped from one program to another. It also has some significance for the eventual commercialization of the SIT. The use of various compounds to improve the mating success of mass reared males could have a major impact on the efficiency of SIT programs. However, the initial experiments reported here will need to be expanded before this approach can be integrated into operational programs.
TL;DR: In mating trials involving wild flies, protein-fed males had a mating advantage over protein-deprived males, however, the addition of protein to the diet did not boost the mating success of mass-reared males in competition with wild or mass- reared males for wild females.
Abstract: The purpose of the present study was to investigate the effect of dietary protein on the mating behavior and survival of male Mediterranean fruit flies (medflies), Ceratitis capitata (Wied.), as a means of enhancing the effectiveness of mass-reared males in sterile release programs to suppress wild populations. Conducted in the laboratory, our study addressed three main questions: 1) Does the inclusion of protein in the adult diet affect mating success of wild and mass-reared males? 2) Are copulation duration and remating tendency of wild females affected by the strain (wild versus mass-reared) and diet (protein-fed versus protein-deprived) of their initial mating partner? 3) Does the inclusion of protein in the adult diet affect the longevity of mass-reared males? In mating trials involving wild flies, protein-fed males had a mating advantage over protein-deprived males. However, the addition of protein to the diet did not boost the mating success of mass-reared males in competition with wild or mass-reared males for wild females. The inclusion of protein in the male diet had no apparent effect on female remating tendency, copulation duration, or male longevity. Independent of male diet, we found no difference between wild and mass-reared males in the duration of copulations with wild females, and wild females mated initially to wild and mass-reared males displayed similar remating propensity. The implications of these findings for SIT are discussed.
TL;DR: It is demonstrated that, from a qualitative standpoint, wild medfly populations world-wide have not yet evolved specific sexual behaviors indicative of incipient pre-mating isolation mechanisms under local natural selection, and the same mass reared strain can be used worldwide, as long as it fulfills the standard quality control requirements.
Abstract: The use of the Sterile Insect Technique to control and/or eradicate insect pest populations has been extensively applied to medfly. However, patented differences in sexual compatibility between populations or strains from different origins has been a serious concern to a wider use of sterile flies, and in particular sterile males of genetic sexing strains (GSS). In the present experiments, the sexual compatibility and mating performance of flies from 9 countries representing 5 continents and 4 GSS were measured. It is demonstrated that, from a qualitative standpoint, wild medfly populations world-wide have not yet evolved specific sexual behaviors indicative of incipient pre-mating isolation mechanisms under local natural selection. Wild medfly populations are as sexually compatible with GSS as they are with other wild populations. On that basis, the same mass reared strain can now be used worldwide, as long as it fulfills the standard quality control requirements.
TL;DR: Analyses of more than 300 videotaped courtships of wild and mass-reared medflies from Costa Rica showed that the tendency for male and female to align themselves facing directly toward each other increased, and that the distance between them decreased as courtship proceeded.
Abstract: Analyses of more than 300 videotaped courtships of wild and mass-reared medflies from Costa Rica showed that the tendency for male and female to align themselves facing directly toward each other increased, and that the distance between them decreased as courtship proceeded. More direct alignments and shorter distances between the flies at the moment the male jumped onto the female were correlated with greater female acceptance of copulation. There were no consistent differences in durations of components of intermittent buzzing songs or male size between successful and unsuccessful courtship in either strain. Several possible cues may release different courtship responses: males of both strains tend to initiate both continuous vibration and intermittent buzzing after reduction of the distance to the female; slow creeping toward the female was associated with longer courtships that had failed to lure the female close; and females tended to turn to face more directly toward the male soon after the male began continuous vibration, and especially after he began intermittent buzzing. Females became progressively more immobile as courtship progressed, especially soon after intermittent buzzing began. There were numerous differences between strains. Mass-reared males were more likely to mount females without previous courtship than were wild males. Wild males initiated continuous wing vibration when farther from the female and when the female was looking less directly toward them, but the two strains did not differ in the distances and angles at which males initiated intermittent buzzing and jumped. Wild males were more likely to creep toward the female during intermittent buzzing. Mass-reared females but not wild females were more likely to copulate when the proportion of time the male had spent in intermittent buzzing was low, and if the courtship began when the flies were nearer each other. Wild but not mass-reared females were less likely to copulate if courtship was shorter. Possible coevolution of female responses with the five different male courtship traits that differ between mass-reared and wild flies are discussed.
TL;DR: Observations of predation by fire ants on loggerhead sea turtle hatchlings on Cape San Blas, Florida provide observations of fire ant predation on amphibian and reptilian eggs and hatchlings.
Abstract: Red imported fire ants, Solenopsis invicta Buren, were introduced to North America in the 1930s (Buren 1972). Since their introduction, fire ant distribution and abundance has continued to increase dramatically. Fire ants have infested more than one hundred million hectares and expanded their range throughout most of the southeastern United States (Callcott & Collins 1996). Fire ants are an omnivorous and opportunistic species, and are often aggressive predators and competitors of native species. Fire ants have the potential to negatively affect vertebrates (Allen et al. 1994). Oviparous species may be especially vulnerable to fire ant predation, particularly ground nesting birds and reptiles (Allen et al. 1994, Allen et al. 1997, Tuberville et al. 2000, Wojcik et al. 2001). Observations of fire ant predation on amphibian and reptilian eggs and hatchlings have been reported for numerous species (Landers et al. 1980, Mount et al. 1981, Freed & Neitman 1988, Montgomery 1996, Allen et al. 1997, Buhlmann & Coffman 2001). The occurrence of red imported fire ants in green sea turtle, Chelonia mydas, and loggerhead sea turtle, Caretta caretta, nests have been documented (Wilmers et al. 1996, Moulis 1997), however few researchers have been able to document observations of hatchling mortality due to fire ants. Hatching sea turtles may be particularly vulnerable to fire ant predation. Sea turtles are oviparous, subterranean nesting species. Prior to hatchling emergence from the nest, newly hatched turtles remain in the ground for up to seven days (Lohmann et al. 1997), during which they may be susceptible to injury from fire ants. In addition, fire ants primarily feed on high protein resources during brood production in late spring, which coincides with the start of sea turtle nesting season. In this paper, we provide observations of predation by fire ants on loggerhead sea turtle hatchlings on Cape San Blas, Florida. Cape San Blas, a coastal barrier island along the Northern Gulf of Mexico, supports the largest density of nesting loggerhead turtles in northwest Florida (Fig. 1). Encalada et al. (1998) identified this group of nesting loggerhead sea turtles as genetically distinct from other nesting populations in southeastern United States. Surveys for nesting sea turtles have been conducted every year since 1994 along Eglin Air Force Base property on Cape San Blas by foot and on ATV. Two surveyors conducted daily monitoring surveys of the 5-km area from 6:00 am to 10:00 am every morning from May 15 to August 15. From August 15 to October 31, nests were observed daily for signs of hatchling emergence or depredation. Nest inventories were conducted 72 h after first emergence or after 85 days of incubation, and number of hatched, unhatched, and depredated eggs was recorded. Red imported fire ant presence was not recorded in sea turtle nests on Cape San Blas before 1995 (Table 1). In 1995, fire ants were observed on one of 60 loggerhead sea turtle nests; however, fire ant induced hatchling mortality was not documented. In 1996, fire ant presence was not recorded on any of the 25 loggerhead sea turtle nests. Fire ants were observed again in 1997 on 14 of 54 loggerhead nests (25.9%). Hatchling mortality was witnessed at two of the 54 nests (3.7%). Upon excavation of one nest, fire ants were observed consuming one sea turtle hatchling that had cracked (pipped) the egg shell, entering and stinging a live turtle within a second pipped egg, and stinging a third hatchling. In the second nest, fire ants were observed consuming an undetermined number of pipped eggs, and skeletonizing five hatchlings before emergence from the nest. In 1998, fire ants were observed on 10 of 57 nests (17.5%). Fire ant depredation resulted in mortality of 23 hatchlings, combined in three of the 57 nests (5.3%). Hatchling mortality was not recorded in the remaining seven fire ant infested nests. In 1998, surveyors observed one hatchling being consumed by fire ants near the nest surface. Upon excavation of the nest, an additional twenty dead hatchlings and one live hatchling were observed covered with fire ants. Fifteen live hatchlings were removed from the infested nest and released. Injures observed on numerous live hatchlings included blinding due to removal of eyes and wounds on head and flippers due to necrotizing fire ant stings. All fire ant induced hatchling mortalities were observed in nests left to incubate in-situ along the North beach, not in the nests relocated to East beach.
TL;DR: In the Mediterranean fruit fly, virgin females are preferentially attracted to the volatile male pheromone over host fruit odors, suggesting a male role in modulation of female olfactory-driven behaviors.
Abstract: Studies on behavior of tephritid fruit flies have historically focused on the interaction of external stimuli such as temperature, semiochemicals, seasonality, etc., or the interactions of flies between and among species for an number of observed behaviors such as mating, pheromone calling and oviposition. While descriptive behaviors represent much of what we know about these pest species, less is known about the underlying physiological mechanisms which function in priming or modulation of the observed behaviors. In the Mediterranean fruit fly, virgin females are preferentially attracted to the volatile male pheromone over host fruit odors. This behavior switches as a result of mating. Factors from the male accessory gland have been shown to facilitate the switch suggesting a male role in modulation of female olfactory-driven behaviors. Other physiological factors are likely to further influence the degree to which female behaviors are influenced.
TL;DR: The effects of male size and other morphometric traits as determinants of male mating success were evaluated under field cage conditions and it was found to be strain dependent and flies from the wild were on average bigger than laboratory ones.
Abstract: The effects of male size and other morphometric traits as determinants of male mating success were evaluated under field cage conditions. Males of the laboratory Seib6-96 strain were released into field cages with males and females of a wild population from the Patagonian region. Mating pairs were classified as ‘successful’, while unmated flies were labeled as ‘unsuccessful’. Five morphometric traits were measured in a sample of 141 unsuccessful and 149 successful males: eye length (EL), head width (HW), thorax length (TL), face width (FW), and wing length (WL). An exploratory non-parametric Spearman’s rank correlation test indicated that mated males were in average larger for all traits (P < 0.01) except FW, indicating that with the exception of FW all traits are positively correlated with mating success. Step-wise multiple regression and principal component analysis + logistic regression indicated that the most likely targets of selection were TL, EL, and FW. The two former are positively corre...
TL;DR: The oviposition behavior of Spodoptera frugiperda (J. E. Smith) and natural parasitism of this pest by Trichogramma spp.
Abstract: The oviposition behavior of Spodoptera frugiperda (J. E. Smith) and natural parasitism of this pest by Trichogramma spp. at different phenological stages of corn were evaluated under field conditions. The distribution of S. frugiperda eggs varied according to the phenological stage of the corn. The preferred site for oviposition was the lower region of the plant and the abaxial leaf surface during the early development stages of the crop (4-6 leaves), changing to the middle and upper regions of the plant and the adaxial leaf surface at subsequent stages (8-10 and 12-14 leaves). A larger number of egg masses, and, therefore, of eggs was collected at the 4-6 and 8-10 leaf stages compared to plants in the 12-14 leaf stages. Natural parasitism was low, with a maximum of 2.21% eggs parasitized, especially on the lower and middle parts of the plant. The distribution and degree of parasitism by Trichogramma spp. on different regions of the plant were independent of the developmental stage of the crop. Trichogramma pretiosum Riley was the most frequent parasitoid, found in 93.79% of the parasitized eggs, followed by Trichogramma atopovirilia Oltman & Platner, with 2.07%.
TL;DR: Based on the insects’ occurrence, abundance and damage to their target weeds, and their absence on other non-target Solanum species, several natural enemies that warrant further investigation were identified.
Abstract: Solanum mauritianum Scopoli and Solanum sisymbriifolium Lamarck are major exotic weeds in South Africa, while Solanum viarum Dunal is similarly problematic in the United States of America. All three species are native to northeastern Argentina and southeastern Paraguay, where they were surveyed for natural enemies in February 1998. Insect agents for Solanum weeds have a tendency to extend their host ranges to include non-target Solanum species, in particular cultivated eggplant (S. melongena L.), during laboratory trials, making it difficult to promote their release. To facilitate the interpretation of such results, other native and cultivated Solanum species that grew in close proximity to the target species were also surveyed to give an indication of the insects’ field host ranges. During the survey period, 19 insect herbivore species were recorded on S. mauritianum, while 8 species were recorded on each of S. sisymbriifolium and S. viarum. Based on the insects’ occurrence, abundance and damage...
TL;DR: Experiments in Costa Rica and Honduras determined that both Metamasius hemipterus L. and Rhynchophorus palmarum L. could be captured in the same trap using pheromone lures emitting a mixture of their male-produced aggregation pherOMones.
Abstract: Experiments in Costa Rica and Honduras determined that both Metamasius hemipterus L. and Rhynchophorus palmarum L. could be captured in the same trap using pheromone lures emitting a mixture of their male-produced aggregation pheromones. Mass trapping of both species was conductedin commercial palmito palm (Bactris gasipaes, Kunth) over 16 months using a combination lure and insecticide-laden sugarcane at a density of 4 traps/ha. Capture rates of M. hemipterus were initially high and declined significantly while capture rates of R. palmarum were initially low andremained relatively constant. Pupae found in and damage to palmito declined significantly in plots with traps compared to pre-trapping levels and to control plots without traps. Yields of palmito palm increased in all plots but increased most in plots with traps.
TL;DR: The developmental rate of adult parasitoids increased linearly with that of female hosts depending on the quality of the rearing substrate for the mealybug, and Parasitoids reared from these mealybugs did not possess desirable characteristics for biological control.
Abstract: Biological control programs of Maconellicoccus hirsutus (Green), in the Caribbean have relied on Japanese pumpkins and sprouted potatoes as hosts for rearing both the mealybug and its parasitoids. However, seasonal shortages of these substrates have necessitated that others be found with equal or better qualities for sustaining large mealybug populations. In this paper, we report experiments comparing mass-rearing M. hirsutus on acorn squash (Cucurbita pepo L. var. ‘Turbinata’), chayote (Sechium edule [Jacques]), and prickly pear, Opuntia ficus-indica [L.]) with Japanese pumpkin and sprouted potato. In addition, a simple meridic diet based on canned pumpkins was developed and compared. Acorn squash produced large quantities of females (up to 1,300 per squash) with a life cycle and reproductive potential equal to that of mealybugs reared on Japanese pumpkin. Parasitoids reared on these mealybugs developed normally and had a female-biased sex ratio similar to those reared on mealybugs on Japanese p...
TL;DR: If gift size is shown to influence female reproductive fitness, then nuptial gifts may play a large role in the evolution of male body size.
Abstract: Many male insects provide somatic nuptial gifts that may strongly influence reproductive fitness by insuring an effective copulation or by increasing paternal investment. In the striped ground cricket, Allonemobius socius (Scudder), females receive a nuptial gift by chewing on a specialized spur on the male’s hind tibia during copulation. Using a series of no-choice trials, we attempted to quantify gift magnitude and to determine the relationships between male size, gift contribution, and male mating success. Tibial spur chewing duration was a significant predictor of gift contribution (F1,17 = 17.02, P < 0.001) and the magnitude of the gift ranged between 0.2% and 8% of the male’s body mass, implying that females receive mostly hemolymph. Large males produced bigger gifts than small males (2.52 ± 0.59 mg vs. 1.33 ± 0.28 mg, t17 = 1.88, P < 0.05, respectively) and females were more likely to mate with larger males (F1,39 = 4.76, P < 0.05). If gift size is shown to influence female reproductive fi...
TL;DR: Foreign exploration for natural enemies of pink hibiscus mealybug, Maconellicoccus hirsutus, was conducted in Australia from 2000 to 2002 with minor population peaks in the summer months.
Abstract: Foreign exploration for natural enemies of pink hibiscus mealybug, Maconellicoccus hirsutus, was conducted in Australia from 2000 to 2002. In Queensland, the predaceous beetle Cryptolaemus montrouzieri, the predaceous drosophilid fly, Cacoxenus perspicax and the encrytid parasitoid Gyranusoidea indica were recovered. In Western Australia and the Northern Territory a predatory noctuid, Mataeomera sp., an aphelinid parasitoid Coccophagus sp., and a probable encyrtid hyperparasitoid, Coccidoctonus sp. were reared from M. hirsutus on a native Hibiscus species. A field study was conducted from February 2000 to March 2002 in Sherwood, Queensland to document the seasonal phenology of M. hirsutus in its native habitat on its preferred host, Hibiscus rosa-sinensis. Populations of the mealybug stayed at or below detectable levels for most of the study with minor population peaks in the summer months.
TL;DR: The probability of Petapa females remating depended more on the origin of the male and was negatively associated with the duration of the first mating, but these variables had no effect on remating tendency of Guate females.
Abstract: Mating and remating of two laboratory strains (Petapa and Guate), one wild population (Antigua) of Ceratitis capitata (Wiedemann) and one of the hybrids between them were studied under laboratory conditions. No evidence of sexual isolation at first mating was found among them. Remating frequency was higher under crowded conditions for the two laboratory strains. The probability of Petapa females remating depended more on the origin of the male and was negatively associated with the duration of the first mating, but these variables had no effect on remating tendency of Guate females. Matings by Petapa males were significantly less prolonged than those of Guate or hybrid males. With respect to remating, Petapa non-virgin females preferred Petapa to Guate males.
TL;DR: It has been suggested that development of an efficient strain for world-wide application shall be based on the most competitive strains (such as Madeira strain), and only individuals with the most pronounced pattern of male courtship should be selected as founders.
Abstract: The objective of the study was to compare courtship behavior of various wild and mass reared medfly strains, in order to document the degree of diversity in courtship behavior among medfly populations and to assess its implications for strategy of application of the Sterile Insect Technique. Recordings of medfly courtship behavior were collected from several locations world-wide using a standard protocol. Qualitative and quantitative analysis of the collected behavioral materials was conducted. No major differences were found among the strains both in male and female behavioral repertoire, which indicates general lack of behavioral incompatibility among the strains studied. However, the analysis revealed several qualitative and quantitative differences in courtship details among locations. The females from Madeira strain were more “choosy” then those from other strains, rejecting male courtship most frequently in spite of the fact that the males from this strain displayed their courtship activiti...
TL;DR: The results support the concept that releasing males only will make the Sterile Insect Technique more effective, since sterile males will be virgin and therefore, more prone to mate.
Abstract: The effect of age on the mating propensity of both wild and laboratory-reared Mediterranean fruit flies, Ceratitis capitata (Wiedemann) was investigated under laboratory and field cage conditions. The optimal age for wild flies ranged from 7 to 13 days, whereas in laboratory-reared flies it was between 3 and 5 days old. Virgin flies were selective and more prone to mate than flies that were held with both sexes combined and therefore, had a chance to mate before the test. The difference among ages in laboratory-reared flies was significant only in virgin flies. Virgin females showed a tendency to increase their mating propensity as they got older, whereas virgin males showed a bimodal pattern, with peaks at 4 and 11 days old. When flies of both strains and different ages were combined, laboratory-reared females accounted for 72% of the all the matings and most matings were by 4-day-old females. Wild males accounted for 67% of all the matings and the maximum number of matings were by 10-day-old ma...