Showing papers in "Annals of The Entomological Society of America in 1961"
TL;DR: It was concluded that species diversity play an important role in preventing population outbreaks and where possible in cultivation, faunal and floral varieties should be encouraged.
Abstract: Species diversity and complexity of association among species were found essential to the stability and balance of the community system. The community associated with Brassica oleracea L. (Cruciferae) was studied on plants grown in single-species planting and on plants grown in the mixed vegetation of a 15-year fallow field. Approximately 300 species of plants and 3,000 species of heterotrophs existed in the fallow field and these provided species diversity. In 1957, 27 taxa were associated with B. oleracea grown in mixed-species planting and 50 taxa were associated with it in the single-species planting. Three to four times as many parasitic and predaceous taxa were present in the single-species planting. Aphid, flea beetle, and lepidopteran populations reached outbreak levels in the single-species planting, but no such outbreaks occurred in the mixed-species planting. These trends were substantiated in 1958. Thus, it was concluded that species diversity play an important role in preventing population outbreaks. Where possible in cultivation, faunal and floral varieties should be encouraged. The use of specific pesticides and biological control agents to remove pests without sterilization should prove a sound practice.
361 citations
TL;DR: Ant toleration was shown to be associated with the rapidity of oviposition by some parasites, and a list of ant association responses of some common predators suggests the degree to which predation may be suppressed by ants.
Abstract: The ability of ants to increase the abundance of certain Coccidae on citrus is recognized in the practical control of these pests in California. The role of ants in the collection and colonization of foreign parasites of lecaniine scale insects is discussed. In ant-attended lecaniine scale infestations, certain parasite species are little influenced by ants while others are strongly suppressed. Following ant removal from infestations of Saissetia oleae (Bern.) and Coccus hesperidium , the pattern of parasite dominance showed that Metaphycus helvolus Comp. and M. luteolus Timb., although not the most abundant species present, were responsible for the subsequent rapid decrease of their respective scale hosts. In the laboratory, in the absence of parasites, heavy accumulations of honeydew may cause a slight retardation in the growth rate and a decrease in survival of some scale insects. The Argentine ant, Iridomyrmex humilis Mayr, possesses no unique capacity for physiological stimulation of scale development and survival beyond that provided by mechanical removal of accumulated honeydew by water-washing. Ant toleration was shown to be associated with the rapidity of oviposition by some parasites. In the exceptions to this rule, certain parasites requiring a long period for egg deposition were less sensitive to nearby moving objects and therefore little influenced by the presence of ants, while other species with short oviposition periods were easily disturbed by any nearby moving objects and therefore would not tolerate the presence of ants. Disturbance by ants resulted in from 27.4% to 98.4% reduction in parasitization, depending on the parasite species. A list of ant association responses of some common predators suggests the degree to which predation may be suppressed by ants.
133 citations
TL;DR: Adult American cockroaches were injected with an aqueous solution of 1-C14-sodium acetate, and held for 24 hours, and analysis of the fatty acid methyl esters by gas-liquid chromatography and column chromatography demonstrated the relative distribution of radioactivity to be similar for both sexes.
Abstract: Adult American cockroaches (Periplaneta americana L.) were injected with an aqueous solution of 1-C14-sodium acetate, and held for 24 hours. On analysis, the rate of fatty acid synthesis from C14-acetate was found to be 2.5 to 4.7 times greater in male than in female cockroaches. Analysis of the fatty acid methyl esters by gas-liquid chromatography demonstrated the relative distribution of radioactivity to be similar for both sexes. Both the male and female cockroaches incorporated approximately the same percentage of radioactivity into the unsaponifiable fraction. Fractionation by column chromatography demonstrated that 59% to 68% of the radioactivity behaved as hydrocarbons and 5% to 8% as sterols. None of the radioactivity in the hydrocarbon fraction behaved as squalene when analyzed by paper chromatography. Only low levels of radioactivity were found in the digitonin precipitates of the sterol fraction, none of which showed distinct peaks corresponding to either the Δ5 or Δ5,7 sterol acetates following acetylation and chromatography on alumina.
131 citations
TL;DR: Three different densities of planting were employed in this investigation of the influence of plant spatial patterns on the animal community associated with Brassica oleracea L. (Cruciferae); an inverse relationship was found between plant density and the total number of animal taxa present in the various plantings.
Abstract: Three different densities of planting were employed in this investigation of the influence of plant spatial patterns on the animal community associated with Brassica oleracea L. (Cruciferae). Plants were spaced at 6 inches, 18 inches, and 9 feet in rows that were, respectively, 6 inches, 36 inches, and 9 feet apart, so that on equivalent areas of 7,500 square feet there were totals of 30,600, 1,768, and 80 plants, respectively. An inverse relationship was found between plant density and the total number of animal taxa present in the various plantings. The proportion of herbivore taxa to carnivore taxa was greatest in the dense planting, least in the dispersed one, but the density of many herbivores in the sparse and dispersed plantings was more than five times that in the dense planting. Plant survival in nature often depends upon a spatial pattern of dense design.
88 citations
TL;DR: Maxillectomized fourth-instar larvae fed and grew well on some Plantaginaceae, Compositae, and members of families closely allied to the Solanaceae, and some of these plants were occasionally accepted by intact larvae.
Abstract: The larvae of P. sexta normally feed only on Solanaceae. Amputation of the maxillae led to continuous feeding on dandelion ( Taraxacum officinale ), a normally rejected plant, when no other food was available. Amputation of the antennae and the labial palpi did not have a similar effect. The chemoreceptors of the maxilla are confined to the third segment of the palpus and to the headpiece, a protuberance of the first segment. Removal of both of these groups of chemoreceptors led to as much feeding on dandelion as did removal of the entire maxilla. Amputation of the headpieces alone had an intermediate effect while amputation of the third segments alone had no effect. Maxillectomized larvae retained a reduced ability to distinguish between the leaves of dandelion and tomato, the normal host. They became adapted to dandelion and usually chose it over tomato in preference tests. They also fed more extensively on bland media such as an agar and cellulose powder gel than did intact larvae, suggesting that the maxillae spontaneously inhibit feeding. Maxillectomized fourth-instar larvae fed and grew well on some Plantaginaceae, Compositae, and members of families closely allied to the Solanaceae. Some of these plants were occasionally accepted by intact larvae. Other plants were either completely rejected or eaten in small quantities.
83 citations
TL;DR: An intensive and prolonged search for the larvae of Phlcbotomus sand flies in a variety of natural habitats in Panama resulted in the collection of 2258 larvae belonging to at least 15 of the 60-odd species now known from the area.
Abstract: An intensive and prolonged search for the larvae of Phlcbotomus sand flies in a variety of natural habitats in Panama resulted in the collection of 2258 larvae belonging to at least 15 of the 60-odd species now known from the area. A number of the species are quite specific in their habitat requirements, some living on the surface of fallen dead leaves on the forest floor while others burrow an inch or more beneath the soil surface. Methods used include a sugar solution notation technique, which is described, and simple searching of likely habitats. The scanty published information is reviewed.
76 citations
TL;DR: The phallus is reviewed for the first time as a character important for the separation of the genera, whose nomenclature and synonymies are outlined and discussed.
Abstract: The seven genera recognized in the Belostomatidae pertain to three new subfamilies: LETHOCERINAE, with the one genus Lethocerus; HORVATHINIINAE , with the single genus Horvathinia ; and BELOSTOMATINAE, with the five genera Limnogeton, Hydrocyrius (= Poissonia , = Diplonychus auctt. nec Laporte), Diplonychus (= Sphaerodema ), Belostoma , and Abedus . Only Lethocerus occurs in both hemispheres; Abedus, Belostoma , and Horvathinia are American, while Lmnogeton, Hydrocyrius , and Diplonychus are Old-World genera. The phallus is reviewed for the first time as a character important for the separation of the genera, whose nomenclature and synonymies are outlined and discussed. The taxonomy, phylogeny, zoogeography, and paleontology of the subfamilies and genera are treated, and keys are provided for generic identification.
73 citations
TL;DR: Except for the ornithophilic species occurring in woodland habitats, preferences for mammals and birds were (within the habitats studied) generally related more closely to host size than to any other apparent factor.
Abstract: A rapid method for capturing simuliids attracted to and feeding on hosts is described. Engorged and nonengorged specimens readily entered the trap. The method was superior to human visual observation in detecting black fly feeding activity on avian hosts.
The blood-sucking females were divided into two categories, those feeding on birds (ornithophilic) and those feeding on mammals (mammalophilic). Most avian feeders exhibited marked habitat and stratification preferences. Differences in the number of flies attracted to various sizes of simultaneously exposed birds were significant at the 5% level. Except for the ornithophilic species occurring in woodland habitats, preferences for mammals and birds were (within the habitats studied) generally related more closely to host size than to any other apparent factor. Engorgement rates were closely related to the attractiveness of the hosts. Simulium meridionale Riley and Eusimulium aureum (Fries) were vectors of Leucocytozoon parasites to turkeys, as was S. rugglesi N. & M. to ducks. Prosimulium magnum D. & S., S. decorum Walk., S. luggeri N. & M., S. jenningsi Mall., S. venustum Say, and S. vittatum Zett. were occasional livestock pests.
56 citations
TL;DR: Various factors which may limit the effectiveness of Trioxys utilis against its host are discussed, and its present distribution, hosts, and hyperparasites are noted.
Abstract: Descriptions and illustrations are given of the adult, the egg, the three larval instars, and the larval head structures, together with illustrations of the male genitalia and of the ovaries and associated structures. Under constant conditions in the laboratory, (1) unmated females produced male progeny only, mated females produced male progeny only, mated females produced both sexes in a 1:1 ratio, and multimated males supplied lesser amounts of sperm in successive matings so that the male-female ratio of progeny went as high as 24:1; (2) though oviposition occurred in aphids of all stages, those of the first three instars were preferred; (3) maximum adult longevity of honey-fed females was 27 days at 50° F.; (4) superparasitism was common, the female apparently being unable to detect a parasitized host, and multiple strikes also were common; (5) reproductive capacity, based on number of eggs per female, ranged between 141 and 179; (6) durations of the various life-cycle stages were: egg 52-53 hours, first-instar larva 9-12 hours, second instar 32-34 hours, third instar 69-71 hours, pupa about 73 hours; (7) first-instar larvae fed almost exclusively on the trophamnion cells and feeding of second-instar larvae was nearly the same, and all contents of the aphid were consumed during the first half of the third instar; (8) with the complete life cycle at 70° F. requiring about 10 days, there are possibly 17 generations per year in the field; (9) a facultative diapause, usually lasting about 120 days, was found during the summer and fall months; (10) aphid defenses against parasitization included the jumping habit of the aphid when disturbed, and production of copious amounts of honeydew which often hindered or trapped the parasite. The jumping habit is partially overcome by the use of the ventral prongs on the parasite's abdomen, which serve to hold the aphid during oviposition. Various factors which may limit the effectiveness of Trioxys utilis against its host are discussed, and its present distribution, hosts, and hyperparasites are noted.
48 citations
TL;DR: T. gertschi (and, by implication, also L. pilifera ), compared to the remaining Thysanura (families Nicoletiidae and Lepismatidae), is characterized by a large number of primitive characters.
Abstract: TRICHOLEPIDION gertschi was found under decaying hark and in rotten logs of Douglas-fir in the mesophytic forest of the northern California Coast Range. It is closely related to the Baltic amber Lepidothrix pilifera Menge, differing mainly by the presence of ocelli. T. gertschi (and, by implication, also L. pilifera ), compared to the remaining Thysanura (families Nicoletiidae and Lepismatidae), is characterized by a large number of primitive characters, such as lack of scales, combined with presence of hypodermal pigment; the hypognathous head with exceptionally well developed occipital and postoccipital sclerites; the presence of three pectinate appendages to the laciniae; weakly developed thoracic sternal plates; a large number of abdominal stylets and exsertile vesicles; urosternites composed of a large, transverse sternite and posteriorly situated coxopodites, both elements being well developed even on the eighth and ninth segments of the male; the lack of a proventriculus; and the presence of seven ovarioles in each ovary. Specialized characters probably shared by both genera of Lepidotrichidae are the five-segmented tarsi; the modified ovipositor adapted to insertion of eggs into vegetable tissue; a group of specialized setae on the dorsal surface of the base of the penis; a very large number of testicular follicles; and forwardly directed diverticula of the vasa deferentia functioning as sperm reservoirs. Pairing of mature sperms in Tricholepidion is considered as a condition precursory to the development of spermatophores as observed in the Nicoletiidae; the presence of sensory cones on the underside of the median caudal filament in the males is equally indicative of relationship with the Nicoletiidae. The Lepidotrichidae are considered to be the most archaic known dicondylous insects ; their relic character is further stressed by their actual geographic distribution.
48 citations
TL;DR: Larvae of the Trinidad DDT-resistant strain when placed in DDT suspensions excreted long streamers of peritrophic membrane containing quantities of unabsorbed DDT.
Abstract: Larvae of the Trinidad DDT-resistant strain when placed in DDT suspensions excreted long streamers of peritrophic membrane containing quantities of unabsorbed DDT. A resistant strain from Puerto Rico showed this property, but resistant strains from Malaya did not. Normal strains when placed in DDT excreted little of the membrane.
TL;DR: The prophase and anaphase chromosomes of Aedes canadensis Theobald are illustrated, as are the metaphase chromosome complements of 16 other species, and Mitosis in Culex salinarius is illustrated and briefly compared with that previously reported for C. pipiens.
Abstract: The prophase and anaphase chromosomes of Aedes canadensis Theobald are illustrated, as are the metaphase chromosome complements of 16 other species, as follows: Culex quinquefasciatus Say, C. salinarius Coquillett, C. tarsalis Coquillett, C. territans Walker, Aedes atropalpus Coquillett, A. hendersoni Cockerell, A. triseriatus (Say), A. vexans (Meigen), A. zoosophus Dyar and Knab, Orthopodomyia alba Baker, O. signifera (Coquillett), Haemagogus equinus Theobald, Anopheles pseudopunctipennis Theobald, Culiseta inornata (Williston), Psoropliora longipalpus complex, and Toxorhynchites rutilans septentrionalis (Dyar and Knab). Additional species examined but not illustrated include Culex restitans Theobald. C. erraticus Dyar and Knab, C. coronator Dyar and Knab, Aedes sollicitans (Walker), Uranotaenia syntheta Dyar and Shannon. Psorophora confinnis (Lynch Arribalzaga), and P. discolor (Coquillett). The chromosomes of 16 of these species had not previously been examined. The number 2n = 6 was found in all species studied. Distinctive chromosome complements were found at prophase in O. alba, O. signifera , and T. r. septentrionalis , and at metaphase for Anopheles pseudopunctipeiinis . Except for this last, the chromosome complements of the species examined at metaphase are quite similar. Mitosis in Culex salinarius is illustrated and briefly compared with that previously reported for C. pipiens . These studies were made on brain tissue of prepupae, using the squash technique with aceto-orcein as the stain, and these techniques are discussed. Future work suggested includes studies of salivary gland chromosomes and of meiosis. continued search for unique karyotypes, the use of different tissues and techniques, and studies of mitotic stages other than metaphase.
TL;DR: The protonymphal stage lasted significantly longer in the male progeny from virgin females, while the deutonymphal stage tended to be shorter, however, the total elapsed time from egg to adult for male or female progeny was not significantly different.
Abstract: Macrocheles muscaedomesticae is a free-living predator of the egg, and to a lesser extent of the larva, of Musca doviestica . In the present study, emphasis is placed up standardization of general rearing conditions and a substrate (ground steer manure plus 10% soybean oil meal, moistened) as well as definition of biological performance of this mesostigmatic mite under these conditions. Eggs from virgin females were smaller (0.370 by 0.249 mm.) than eggs from mated females (0.374 by 0.256 mm.), and required a longer incubation period. These individuals spent less time as larvae; neither difference in the first two stages was significant. The protonymphal stage lasted significantly longer in the male progeny from virgin females, while the deutonymphal stage tended to be shorter. However, the total elapsed time from egg to adult for male or female progeny was not significantly different. The preoviposition period in fertilized females (53.5 hours) exceeded that in virgin females (48 hours), but not significantly. Significantly more eggs were laid by virgin females (91.7) than by fertilized females (61.4). The maximum recorded 24-hour egg production from a virgin female was 28, from a fertilized female 25; the average daily production was 7.70 and 5.29, respectively. The average life span of fertilized females (23.9 days) was close to that of unfertilized females (24.3 days) ; the male life span was shorter, averaging 15 days.
TL;DR: The two-spotted spider mite regulates its water loss by virtue of a relatively impermeable cuticle and control of diffusion of water from the tracheal system by movements of the mandibular plate.
Abstract: The two-spotted spider mite regulates its water loss by virtue of a relatively impermeable cuticle and control of diffusion of water from the tracheal system by movements of the mandibular plate. The diapause form exhibits a reduction in oxygen consumption coupled with reduced water loss from the tracheal system. Water intake in the feeding mite equals up to one quarter of the total weight within 1 hour. Fluids are bypassed to the hindgut, where small ions can be absorbed, and the water rapidly eliminated. Diffusion from the trachea can account for a large part of water excretion under conditions of low relative humidity.
TL;DR: Audiospectrographs of sounds of 11 species of Hemiptera from the families Cydnidae, Pentatomidae, Reduviidae, Phymatidae, phymatids and reduviids, and 13 species of Homoptera are presented and discussed, and no positive evidence of function for any of these sounds has yet been presented.
Abstract: Audiospectrographs of sounds of 11 species of Hemiptera from the families Cydnidae, Pentatomidae, Reduviidae, Phymatidae, and Corixidae, and 13 species of Homoptera from the families Cercopidae, Cicadellidae, Membracidae, and Fulgoridae are presented and discussed. These sounds can be grouped as common sounds, courtship sounds, or disturbance sounds, depending on the circumstances under which they are produced. Hemiptera produce noises by moving a movable scraper over a stationary file, while Homoptera produce noises by vibrating tergal abdominal timbals. Phymatids and reduviids appear to use fewer teeth per stridulation than the total number present on the file. Also, three different patterns of head movement associated with sound production are found among the five subfamilies of Reduviidae recorded. In general, sounds produced by Hemiptera are much more uniform than the irregular series of ticks and trills produced by Homoptera. No positive evidence of function for any of these sounds has yet been presented, although many authors have linked sound production and courtship in several families of Hemiptera and Homoptera. Because they are such soft sounds, it is not likely that they function as the primary mechanism of species congregation as is the case in loud-singing insects, but rather that they function at a secondary level after congregation has occured in response to other stimuli. These soft noises probably arose in conjunction with moving visual cues in the courtship behavior of Hemiptera and Homoptera, and became functional in disturbance situations only after they became relatively intense. Species which occur in the same sound environment produce sounds which differ primarily in number of tooth-strikes or timbal-vibrations per pulse, in timbalvibration rate, in number of pulses per phrase, and in pulse rate. Special equipment has been constructed to reduce background noise and to amplify the soft sounds produced by these animals while observing them at the same time. Changes made in the tape recorder circuits and a transistor amplifier designed especially for recording soft sounds between 0.3 and 12 kcps. are described. The next logical step to be taken in the analysis of these sounds is to establish a predictable response to some naturally produced sounds, and then to proceed to analyze experimentally its function and its means of transmission and reception.
TL;DR: The reduviid venation is distinct from that of the other Cimicomorpha, and is best characterized by a narrow postcubital sector containing subparallel Pcu and 1st A veins.
Abstract: Evidences of the identity of the veins of the cubitalanal field of the hemipterous wing are given. In the fore wing of auchenorrhynchous Homoptera these veins are: Cm (anterior to the clavus) ; Cu2 (closely associated with the claval furrow) ; Pcu, 1st A, and 2d A (in the clavus). In Heteroptera Cu2 is absent, and the clavus contains only Pcu and 1st A. There is no anal lobe in either suborder, the clavus representing the postcubital region of the fore wing. In the hind wing of Auchenorrhyncha the veins of the cubital-anal field are the same as in the fore wing; a cubital furrow lies just behind Cu2, and the anal fold lies just behind 1st A. In Heteroptera this region of the hind wing is similar, except that Cu2 is absent, and the cubital furrow often is bifid and may contain secondary veins between its branches. In both Auchenorrhyncha and Heteroptera the anal lobe of the hind wing usually is well developed, and the jugal lohe is always absent. In the Cimicomorpha the hind-wing venation of the Miridae, Nabidae, Microphysidae, Anthocoridae, Joppeicidae, Thaumastocoridae, and Velocipedidae is of the same basic type, characterized particularly by the absence of Sc and by having a Y- or V-shaped pattern of Pcu and 1st A. The tingids resemble this group, but have a distinct Sc. The nabids and microphysids seem exceptional in sometimes having R and M separated distally, as in the Pentatomomorpha. The reduviid venation is distinct from that of the other Cimicomorpha, and is best characterized by a narrow postcubital sector containing subparallel Pcu and 1st A veins. Venation is useful in distinguishing subfamilies of the Nabidae. Anthocoridae, and Reduviidae; in the Reduviidae it serves in characterizing three major groups of subfamilies.
TL;DR: Preliminary mass spectrometric analysis indicates that the stink glands of the adult and nymph of the fossorial cydnid Scaptocoris diveryens are a mixture of a series of 7 aldehydes, 2 furans, and 2 quinones, and the secretion is probably used principally as a defense against predators.
Abstract: The stink glands of the adult and nymph of the fossorial cydnid Scaptocoris diveryens are described. Preliminary mass spectrometric analysis indicates that the secretion is a mixture of a series of 7 aldehydes, 2 furans, and 2 quinones. The secretion is probably used principally as a defense against predators. In petridish tests the vapors of the secretion have a fungistatic or fungicidal action against Fusarium oxysporum f. cubense, confirming Timonin's original observations. Factors which may influence survival of Scaptocoris in certain types of soil are discussed.
TL;DR: Temperature was found to be the main factor influencing the life cycle and longevity of the parasite.
Abstract: Hyposoter exiguae (Viereck), a Nearctic ichneumonid, is a solitary endoparasite of the larvae of several species of Lepidoptera. It prefers to oviposit in late first- and second-instar larvae and emerges from the third. Three larval instars have been observed, the last leaving the host body to spin its cocoon. At 72° to 76° F. the insect spends 2 days in the egg stage, 7 days as a larva, and 7 to 8 days in the cocoon. Females mate only once, but males mate with more than one female. Mated females produce about equal numbers of both sexes; unmated females produce males only. Temperature was found to be the main factor influencing the life cycle and longevity of the parasite. Developmental time at 60° to 80° F. ranged from 33.8 to 14.6 clays. Longevity at 40° to 80° F. ranged from 50.5 to 6.5 days. Percent emergence from cocoons was also related to temperature. Those held longest at 40° F. prior to removal to 72° to 76° F. showed emergence of only 20% as compared with 100% for those held for the shortest period. Spilochalcis albifrons (Walsh) was the most frequent hyperparasite reared. It oviposits in the cocoon of H. exiguae , and its life cycle requires 23 days at 72° to 76° F.
TL;DR: The general anatomy and histology of the female reproductive system and its innervation are described in detail and the nervous system in some unknown manner initiates ovulation and oviposition, and coordinates both internal and external processes.
Abstract: The general anatomy and histology of the female reproductive system and its innervation are described in detail. Contractions of the ampullae, lateral oviducts, and ovaries are rhythmic; they are basically independent of age, sexual and nutritional status, endocrine secretions, and nervous stimuli. The common oviduct does not contract. Ovulation cannot occur without complete maturation of the egg and rupturing of the follicular intima. Both ovulation and oviposition are solely due to the rhythmical contractions of the lateral oviducts and are essentially independent of the activities of the external genitalia. In the intact mosquito, however, the nervous system in some unknown manner initiates ovulation and oviposition, and coordinates both internal and external processes. The regulatory oviposition centers are located in the head and thorax.
TL;DR: A comparative system of the anatomical arrangement was made on 10 species, namely, Aedes triseriatus, A. taeniorhynchus, A, fulvus pallens, Psorophora howardii, and Anopheles crucians, finding chief differences found in the shape of the accessory glands, the time of formation of mature spermatozoa, and particularly in the arrangement of the seminal vesicles.
Abstract: A comparative system of the anatomical arrangement was made on 10 species, namely, Aedes triseriatus, A. taeniorhynchus, A. fulvus pallens, A. infirmatus, Psorophora howardii. Culex pipiens quinquefasciatus, Deinocerites cancer, Uranotaenia lowii, Culiseta inornata , and Anopheles crucians . The chief differences found were in the shape of the accessory glands, the time of formation of mature spermatozoa, and particularly in the arrangement of the seminal vesicles. The accessory glands were oval, or elongate, or pear-shaped; in U. lowii and A. taeniorhynchus they were shaped differently in newly emerged males than in older ones. In the Psorophora , the Culex , and the four Aedes species the seminal vesicles were conjoined or fused throughout their length, but in C. inornata, D. cancer, C. lowii , and A. crucians they were separate, connected only at the posterior ends. In the species with conjoined or fused vesicles the transfer of spermatozoa was rapid (10 to 15 seconds) during mating, but this was prolonged to 45 minutes or more in three of the four species with separate vesicles; mating behavior was not observed in Anopheles crucians , which is strikingly different from all the other nine species in the size and musculature of its ejaculatory duct. Active spermatozoa were found in the seminal vesicles within 15 minutes after emergence in P. howardii, D. cancer , and U. lowii ; after 6 hours in A. taeniorhynchus, A. triseriatus, A. infirmatus, C. p. quinquefasciatus, C. inornata , and A. crucians ; and after 20 hours in A. fulvus pallens.
TL;DR: A high correlation between the changes in weight and hatchability is demonstrated and conditioned eggs subjected to various relative humidities showed a progressive loss in Weight and a corresponding decrease in hatchability.
Abstract: At laying, eggs of Aedes aegypti (L) weighed about 5 μ g As the embryo developed and the eggs became conditioned, weight increased to 12 ± 03 μ g Conditioned eggs subjected to various relative humidities showed a progressive loss in weight and a corresponding decrease in hatchability “Optimally” conditioned eggs held at 0% relative humidity at 25° ± 2° C decreased in weight to near 35 μ g in 72 clays at which time hatching ceased Suboptimally conditioned eggs of the same initial weight decreased to the same extent in about 55, 80, 150, 205, and 230 clays in relative humidities of approximately 0%, 30%, 60%, 75%, and 90% respectively A high correlation between the changes in weight and hatchability is demonstrated
TL;DR: Observations on the immature stages and adults, in laboratory cultures, of 33 of the 65 known Panamanian Phlebotomus sandflies, of which 24 species have been reared to the adult stage are included.
Abstract: Observations on the immature stages and adults, in laboratory cultures, of 33 of the 65 known Panamanian Phlebotomus sandflies, of which 24 species have been reared to the adult stage, include the following: (i) General observations on larval food; temperature; feeding habits and other behavior of larvae; feeding habits of adults ; copulation ; fertility of eggs ; longevity ; diapause and quiescence, (ii) Detailed observations on the six principal man-biting species, notes on 27 other species, with tables showing numbers of eggs per female and the times of development from oviposition to adult and for individual stages.
TL;DR: Using laboratory studies indicated that 2.5° C. approximated the threshold temperature that initiates diapause termination of the hibernating second-instar budworm larvae, it was possible to calculate from standard thermograph records the degree- hours that would establish the approximate date when first larval emergence can be expected in the field.
Abstract: Laboratory studies indicated that 2.5° C. approximated the threshold temperature that initiates diapause termination of the hibernating second-instar budworm larvae, Using this temperature as a base, it was possible to calculate from standard thermograph records the degree- hours that would establish the approximate date when first larval emergence can be expected in the field. The data given represent those conditions found in northern Minnesota. However, the method should be applicable to other regions.
TL;DR: In general, offspring from middle-aged and those from old flies had a shorter life span than that of the parental generation; this aging effect was obtained in the first generation.
Abstract: Effects of parental age were followed through nine successive generations, reared at 25° C, for offspring from young, middle-aged, and old parents. The reproductive capacity of offspring from middle-aged flies was initially lower than that of the parental generation, while that of off-spring from old (and also, usually, from young) parents was higher. The offspring from young parents produced viable eggs for a longer period (46 days, increasing to 51 days in the last three generations) than did the parental generation (41 days) ; for offspring from middle-aged parents this period was greater initially (46 days) but dropped to 31 days in the last three generations; with offspring from old parents production of viable eggs always had a shorter duration than in the parental generation and reached a minimum of 25 days. In general, offspring from middle-aged and those from old flies had a shorter life span than that of the parental generation; this aging effect was obtained in the first generation.
TL;DR: The quantity of fluid in the male glands diminishes with successive matings, as does the number of spermatozoa in the seminal vesicles, and changes in the shape and appearance of the glands follow multiple matings.
Abstract: In Aedes triseriatus Say, A. taeniorhynchus Wied., and Psorophora howardii Coq., the male accessory glands possess an anterior region whose fluid contents include large granules, and a posterior region without such granules. In the two Aedes species the fluid and granules are colorless, while in P. howardii the yellow pigmentation of the large granules makes the glandular secretion easily discernible. During mating, the fluid with its granules is always ejected along with spermatozoa and deposited with the latter in the bursa copulatrix of the female. There the granules mass compactly in the form of a rectangular or U-shaped plug, but soon begin to dissolve. In P. howardii the yellow pigment thus released discolors the remaining fluid in the sac, but within 24 to 36 hours the granules have completely disintegrated and no traces of the fluid are evident thereafter. There is no evidence, at present, that the fluid from the accessory glands has a stimulatory effect on the spermatozoa. The quantity of fluid in the male glands diminishes with successive matings, as does the number of spermatozoa in the seminal vesicles, and changes in the shape and appearance of the glands follow multiple matings.
TL;DR: Two purines have been shown to be nitrogenous end products in arthropods, namely uric acid in insects and guanine in spiders (Prosser 1950) and Gasser (1951), on the basis of solubility tests, described not only the concretions in the hindgut but also part of the black fecal pellets as containing Guanine.
Abstract: Two purines have been shown to be nitrogenous end products in arthropods, namely uric acid in insects and guanine in spiders (Prosser 1950).
Blauvelt (1945) found spherical concretions in the hindgut of the two-spotted spider mite which he classed as urates. As no malpighian tubes were present, the glandular cells in the anterior lateral walls of the hindgut (plate 2, Blauvelt 1945) were described as a specialized nephritic organ for the elimination of urates. Gasser (1951), however, on the basis of solubility tests, described not only the concretions in the hindgut but also part of the black fecal pellets as containing guanine. These spherical concretions accumulate in the hindgut and are passed with the fecal pellets.
TL;DR: The absorption and metabolism of 4-C14- cholesterol by nymphal German cockroaches was studied after two weeks on diets containing 0.05% C14-cholesterol with and without the sterol antagonist, cholesteryl chloride, at a 1:10 ratio.
Abstract: The absorption and metabolism of 4-C14-cholesterol by nymphal German cockroaches ( Blattclla germanica (L.)) was studied after two weeks on diets containing 0.05% C14-cholesterol with and without the sterol antagonist, cholesteryl chloride, at a 1:10 ratio. Dietary cholesterol was efficiently utilized when fed alone, with greater than 90% of the ingested sterol retained. Cholesteryl chloride caused only about a 9% to 11% decrease in cholesterol utilization, as determined from the relative amounts of C14 compounds present in the roaches and their excreta. About 93% of the C14 compounds from the roadies behaved chromatographically as free sterols, 5% as esters, and the remainder as more polar compounds. Analyses of the free and esterified sterols by column chromatography and reverse-isotope dilution demonstrated that unchanged cholesterol accounted for 95% of these fractions and another 2.5% behaved like 7-dehydrocholesterol. Xo significant amounts of either C14-labeled bile acids or coprostanol were detected in the excreta.
TL;DR: Fractionation of the unsaponifiable material by column chromatography demonstrated that less than 17% of the radioactive material behaved as hydrocarbons, and more than 40% was eluted in the sterol fraction, indicating that the previously reported absence of sterol synthesis from C14-acetate in the adult house fly is not due to a metabolic block in the biosynthetic pathway between acetate and mevalonate.
Abstract: When 2-C14-mevalonate was injected into male and female house flies ( Musca domestica L.) at 10 micrograms per fly, about the same amount of radioactivity was incorporated into the saponifiable and unsaponifiable lipids after 18 hours. Fractionation of the unsaponifiable material by column chromatography demonstrated that less than 17% of the radioactive material behaved as hydrocarbons, and more than 40% was eluted in the sterol fraction. However, when this fraction was analyzed by digitonin precipitation, only trace amounts of radioactivity were precipitated with the sterol digitonides, indicating that the previously reported absence of sterol synthesis from C14-acetate in the adult house fly is not due to a metabolic block in the biosynthetic pathway between acetate and mevalonate.
TL;DR: The 2-year life cycle of the Engelmann spruce beetle is applicable to both endemic and epidemic infestations, however, the life cycle in any area may vary considerably from year to year because of differing climatic conditions.
Abstract: The 2-year life cycle of the Engelmann spruce beetle is applicable to both endemic and epidemic infestations. However, the life cycle in any area may vary considerably from year to year because of differing climatic conditions. Of major importance in the ecology of the insect is the proportion of adult beetles that emerge and hibernate at the bases of the trees. This is an extremely variable factor. Beetles developing in felled trap trees in well shaded locations may have a longer cycle than beetles developing in nearby standing trees.
TL;DR: The apparent increase in pterine pigments suggests that protein catabolism may be more important than lipids in supplying metabolic energy, and that lipids constitute the major source of energy for development.
Abstract: The purposes of this study were to determine the accordance or disagreement of the milkweed bug egg ( Oncopeltus fasciatus ) with generalizations set forth for eggs of terrestrial oviparous animals, i.e., that a high degree of lipid catabolism is characteristic, that lipids constitute the major source of energy for development, and that the greatest use of lipids occurs in the later stages of development. Eggs were found to contain an average of 32.2 μg. of lipid, or 11.6% of the wet weight. Shortly before hatching, the content was 28.5 μg., or 10.7% of the wet weight. The over-all decrease represented utilization of 11.5% of the initial lipid store, with the decrease occurring mostly in the latter half of development. Lipids therefore do not seem to play as dominant a role in development as expressed by other insect eggs. The apparent increase in pterine pigments suggests that protein catabolism may be more important than lipids in supplying metabolic energy.