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Douglas W Tallamy - One of the best experts on this subject based on the ideXlab platform.
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female choice by scent recognition in the Spotted Cucumber Beetle
Ethology, 2006Co-Authors: Jeremy F Brodt, Douglas W TallamyAbstract:In species that demonstrate female choice, geographically distinct populations can vary in their signal-response behaviors as a result of environmental differences or genetic drift. Observing whether or not females discriminate against males from allopatric populations can establish such signal deviations. Here we compare mating success within and between populations of the Spotted Cucumber Beetle (Diabrotica undecimpunctata howardi) collected from Delaware, Tennessee, Missouri, and New Mexico, USA. A no-choice cross-mating experiment was employed to measure female preference for sympatric and allopatric males. While only two of the populations (Tennessee and Missouri) demonstrated statistically significant female preference for sympatric males, this trend was observed in all populations tested. Further, we show that (i) males from Tennessee, Missouri, and New Mexico differ in their scent, (ii) females may use population-specific scents to discriminate among males, and (iii) females whose antennae have been surgically removed are unable to recognize acceptable mates. New Mexico males, which were never accepted by either Tennessee or Missouri females, became acceptable mates when crowded with Tennessee or Missouri males prior to copulation. We infer that male odor may be an important factor in determining Cucumber Beetle mating success.
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Copulatory courtship signals male genetic quality in Cucumber Beetles
Proceedings of The Royal Society B: Biological Sciences, 2003Co-Authors: Douglas W Tallamy, John Pesek, Mark Burton Darlington, Bradford E PowellAbstract:In the Spotted Cucumber Beetle, Diabrotica undecimpunctata howardi (Coleoptera: Chrysomelidae), males court females during copulation by stroking them with their antennae. Stroking occurs exclusively during the first stages of copulation, after a male has penetrated a female's vaginal duct but before he is allowed access to her bursa copulatrix. Females accept the spermatophore of fast-stroking males and reject those of slow-stroking males by relaxing or constricting muscles distorting the vaginal duct. Here, we measure the repeatability of stroking behaviour within males, examine the effect of losing one antenna on male attractiveness and test whether such female control results in direct phenotypic benefits for the discriminating female or indirect genetic benefits that appear in her offspring. We also use a half-sibling design to quantify the variance and heritability of stroking speed and endurance. Female Beetles were paired with a male that was known to stroke either quickly or slowly. No difference was found in the resulting fecundity or egg-hatching rate of the females, or in the survivorship, development rate, size, age at first reproduction or fecundity of their offspring indicating that no direct benefits are gained by discriminating among males on the basis of stroking speed. There were, however, good-genes benefits for the mates of fast-stroking males. Offspring of fast-stroking fathers were also fast strokers and were more likely to be accepted as mates than offspring of slow-stroking fathers. There was substantial variance among sires in stroking speed and endurance and the heritability of each trait was high. The antennal stroking rate was highly repeatable in successive mating attempts and males with only one antenna were not accepted as mates. The repeatability within males, variability between males and heritability between generations of copulatory stroking combine to provide females with a reliable and honest signal of the genetic quality of courting males.
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male traits under cryptic female choice in the Spotted Cucumber Beetle coleoptera chrysomelidae
Behavioral Ecology, 2002Co-Authors: Douglas W Tallamy, Bradford E Powell, Julie A McclaffertyAbstract:Males of the Spotted Cucumber Beetle (Diabrotica undecimpunctata howardi) rhythmically stroke females with their antennae during copulation. Males that stroke quickly have a higher probability of being accepted as a mate. We determined (1) the mechanism by which females prevent unattractive males from passing spermatophores, (2) whether antennal stroking signals to females the likelihood of receiving a nuptial gift, and (3) if other male traits in addition to stroking are subjected to sexual selection from female preference. Dissections of pairs flash-frozen in copula during and after antennal stroking showed musculature that, when contracted, folded the vaginal duct leading to the female's bursa copulatrix in a way that prevented complete penetration by the aedeagus. These muscles were always contracted while males were stroking and always relaxed after stroking had ceased. Males accepted as mates did not differ from males that failed to pass a spermatophore in either absolute or relative body weight, aedeagus length, or the amount of cucurbitacins (potential nuptial gifts) sequestered in their spermatophores. Although 99% of the Beetles that came to cucurbitacin-rich Cucurbita fruits in the field were males, males that had sequestered cucurbitacins did not stroke females faster than males with no cucurbitacins, and fast-stroking males were not more likely to find and sequester cucurbitacins than were males that stroked more slowly. Males with a cucurbitacin slurry painted on their antennae had no mating advantage over controls. We conclude that females discriminate among males after copulation has begun on the basis of antennal stroking displays (or some trait correlated with stroking speed) that males perform to entice females to relax their bursal sphincter. Copyright 2002.
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Fate of Male-derived Cucurbitacins in Spotted Cucumber Beetle Females
Journal of Chemical Ecology, 2000Co-Authors: Douglas W Tallamy, Piotr M Gorski, Julia K. BurzonAbstract:Using the Spotted Cucumber Beetle, Diabrotica undecimpunctata howardi , as a model species, we begin an examination of the role of dietary cucurbitacins, the bitter tetracyclic triterpenes produced by cucurbits, in the reproductive behavior of luperine chrysomelids that seek these compounds for purposes other than host-plant recognition or nutrition. By manipulating the cucurbitacin content of adult diets, we determine: (1) how males and females partition cucurbitacins between reproductive organs and other tissues, (2) the extent to which males pass cucurbitacins to females during copulation, and (3) if females increase their cucurbitacin stores via multiple matings. After two days of exposure to dietary cucurbitacins, 8.3 times more cucurbitacins per gram dry weight were sequestered in male spermatophores than in the aggregate of remaining male tissues. These cucurbitacin-rich spermatophores were passed to females during mating, and 78.8% of the transferred cucurbitacin was deposited in eggs, 11.8% was irreversibly sequestered in other female tissues, and 9.4% was apparently excreted. Females copulated with 0–15 males prior to accepting a complete spermatophere, but did not accept measurable amounts of cucurbitacin from rejected males. Regardless of when it was received, females lost subsequent receptivity to additional males after accepting a complete spermatophore. The implications of these data are discussed in terms of sexual selection hypotheses and mating behavior in Cucumber Beetles.
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Cucurbitacins: A Role in Cucumber Beetle Steroid Nutrition?
Journal of Chemical Ecology, 1999Co-Authors: Fathi T. Halaweish, Douglas W Tallamy, Eva SantanaAbstract:The conditional role of cucurbitacins as phytosteroid supplements, cholesterol precursors, or ecdysteroid antagonists in the Spotted Cucumber Beetle, Diabrotica undecimpunctata howardi , was investigated in two ways: by comparing larval survival and growth rate on cucurbitacin-rich and cucurbitacin-poor squash cultivars of Cucurbita pepo and by manipulating the presence of cholesterol, phytosteroids, and cucurbitacins in an artificial diet and examining the effects on adult survival and fecundity. Larvae that developed on cucurbitacin-rich roots grew significantly faster and survived as well as larvae on cucurbitacin-poor roots. There was no evidence, however, that adults could substitute cucurbitacins in vital phytosteroid roles. Beetles reared on a cucurbitacin-rich, phytosteroid-poor diet laid significantly fewer eggs and died significantly younger than Beetles with a full complement of dietary phytosteroids and also laid fewer eggs than Beetles with no access to phytosteroids in their adult diet. The data are consistent with the hypothesis that, when the side chain of dietary cucurbitacins can be successfully hydrogenated, these compounds play a nutritional role as substitutes or precursors for structural steroids. In contrast, when the carbon–carbon double bond cannot be hydrogenated, cucurbitacins may become antagonists at ecdysteroid receptors, negatively affecting Beetle fitness.
Julia K. Burzon - One of the best experts on this subject based on the ideXlab platform.
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Fate of Male-derived Cucurbitacins in Spotted Cucumber Beetle Females
Journal of Chemical Ecology, 2000Co-Authors: Douglas W Tallamy, Piotr M Gorski, Julia K. BurzonAbstract:Using the Spotted Cucumber Beetle, Diabrotica undecimpunctata howardi , as a model species, we begin an examination of the role of dietary cucurbitacins, the bitter tetracyclic triterpenes produced by cucurbits, in the reproductive behavior of luperine chrysomelids that seek these compounds for purposes other than host-plant recognition or nutrition. By manipulating the cucurbitacin content of adult diets, we determine: (1) how males and females partition cucurbitacins between reproductive organs and other tissues, (2) the extent to which males pass cucurbitacins to females during copulation, and (3) if females increase their cucurbitacin stores via multiple matings. After two days of exposure to dietary cucurbitacins, 8.3 times more cucurbitacins per gram dry weight were sequestered in male spermatophores than in the aggregate of remaining male tissues. These cucurbitacin-rich spermatophores were passed to females during mating, and 78.8% of the transferred cucurbitacin was deposited in eggs, 11.8% was irreversibly sequestered in other female tissues, and 9.4% was apparently excreted. Females copulated with 0–15 males prior to accepting a complete spermatophere, but did not accept measurable amounts of cucurbitacin from rejected males. Regardless of when it was received, females lost subsequent receptivity to additional males after accepting a complete spermatophore. The implications of these data are discussed in terms of sexual selection hypotheses and mating behavior in Cucumber Beetles.
R. C. Gergerich - One of the best experts on this subject based on the ideXlab platform.
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Comoviruses: Transmission, Epidemiology, and Control
The Plant Viruses, 1996Co-Authors: R. C. Gergerich, H. A. ScottAbstract:Most comoviruses have been shown to be transmitted efficiently by leaf-feeding Beetles in the families Chrysomelidae, Coccinellidae, Curculionidae, or Meloidae. Table I lists the comoviruses, with acronyms used in this chapter, and the Beetle species that have been shown to transmit them. Beetle transmission of glycine mosaic virus (GMV), pea mild mosaic virus (PMiMV), and ullucus virus C (UVC) has not been demonstrated. Comoviruses can be acquired or transmitted by Beetles immediately upon initiation of feeding, although higher frequencies of transmission occur with prolonged feeding. It was once thought that virus transmission by Beetles is a simple mechanical process involving contamination of the mouthparts of the Beetle (Smith, 1965). More recent evidence, however, indicates a complex type of interaction between plant viruses and their Beetle vectors (Fulton et al., 1980; Gergerich and Scott, 1991). The interaction between Beetles and the viruses they transmit has been characterized as circulative because many Beetle-transmitted viruses move into the hemolymph of their vectors after ingestion (Freitag, 1956; Slack and Scott, 1971). In vector species such as the bean leaf Beetle (Cerotoma trifurcata) and the Spotted Cucumber Beetle (Diabrotica undecimpunctata howardi), southern bean mosaic sobemovirus (SBMV) moves from the digestive system into the circulatory system through the midgut (Wang et al., 1994). However, the comovirus bean pod mottle virus (BPMV) does not enter the hemolymph of these species, although it is efficiently transmitted by them (Wang et al., 1992). Moreover, neither SBMV nor BPMV move into the hemolymph of the Mexican bean Beetle (Epilachna varivestis), an efficient vector of these viruses (Wang et al., 1992). As SBMV and BPMV are similar in size and shape, this selective movement through the midgut wall suggests a specific interaction between the virus and some component of the midgut that is required for virus movement through the midgut wall. Because ingested comoviruses are not always found in the hemolymph of their Beetle vectors, it appears that virus circulation in the Beetle is not invariably an important part of the transmission process, and that in some cases the relation between the Beetle and the virus is similar to that found in the foregut-borne type of transmission described for viruses transmitted in the semipersistent manner by aphids (anthriscus yellows virus; Murant et al., 1976) and leafhoppers (maize chloro-tic dwarf virus; Nault and Ammar, 1989). The gradual decrease in the amount of BPMV in Beetles during test feeding following virus acquisition (Ghabrial and Schultz, 1983) is taken to indicate that the virus does not multiply in the Beetle.
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The relationship between feeding and virus retention time in Beetle transmission of plant viruses
Phytopathology, 1994Co-Authors: R. Y. Wang, R. C. GergerichAbstract:Three Beetle vectors of plant viruses, the Mexican bean Beetle (Epilachna varivestis), the bean leaf Beetle (Cerotoma trifurcata), and the Spotted Cucumber Beetle (Diabrotica undecimpunctata howardi), were used to study retention of southern bean mosaic virus (SBMV). After bean leaf Beetles acquired SBMV from virus-infected bean leaves, they were viruliferous for less than 5 days unless they did not feed, in which case they were viruliferous for longer periods. To test the hypothesis that virus retention time is determined mainly by feeding activity that depletes the amount of ingested virus, Mexican bean Beetles, bean leaf Beetles, and Spotted Cucumber Beetles were held at 5-7 C for 1, 2, 3, or 4 wk without feeding after virus acquisition from SBMV-infected leaves
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Entry of ingested plant viruses into the hemocoel of the Beetle vector Diabrotica undecimpunctata howardi
Phytopathology, 1994Co-Authors: R. Y. Wang, R. C. GergerichAbstract:Southern bean mosaic sobemovirus (SBMV) and the cowpea strain of tobacco mosaic tobamovirus (CP-TMV) are found in the hemocoel of some Beetle vectors after they have fed on infected plants. The location in the alimentary canal through which ingested plant viruses enter the hemocoel of the Spotted Cucumber Beetle Diabrotica undecimpunctata howardi was studied. Immunofluorescent and electron microscopy were used to detect the presence of ingested viruses in the gut lumen and the epithelial cells lining the midgut of the Spotted Cucumber Beetle. Virusspecific immunofluorescent microscopy detected bean pod mottle virus and tobacco ringspot virus only in the lumen of the gut; these two viruses cannot be detected in the hemocoel [...]
Julie A Mcclafferty - One of the best experts on this subject based on the ideXlab platform.
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male traits under cryptic female choice in the Spotted Cucumber Beetle coleoptera chrysomelidae
Behavioral Ecology, 2002Co-Authors: Douglas W Tallamy, Bradford E Powell, Julie A McclaffertyAbstract:Males of the Spotted Cucumber Beetle (Diabrotica undecimpunctata howardi) rhythmically stroke females with their antennae during copulation. Males that stroke quickly have a higher probability of being accepted as a mate. We determined (1) the mechanism by which females prevent unattractive males from passing spermatophores, (2) whether antennal stroking signals to females the likelihood of receiving a nuptial gift, and (3) if other male traits in addition to stroking are subjected to sexual selection from female preference. Dissections of pairs flash-frozen in copula during and after antennal stroking showed musculature that, when contracted, folded the vaginal duct leading to the female's bursa copulatrix in a way that prevented complete penetration by the aedeagus. These muscles were always contracted while males were stroking and always relaxed after stroking had ceased. Males accepted as mates did not differ from males that failed to pass a spermatophore in either absolute or relative body weight, aedeagus length, or the amount of cucurbitacins (potential nuptial gifts) sequestered in their spermatophores. Although 99% of the Beetles that came to cucurbitacin-rich Cucurbita fruits in the field were males, males that had sequestered cucurbitacins did not stroke females faster than males with no cucurbitacins, and fast-stroking males were not more likely to find and sequester cucurbitacins than were males that stroked more slowly. Males with a cucurbitacin slurry painted on their antennae had no mating advantage over controls. We conclude that females discriminate among males after copulation has begun on the basis of antennal stroking displays (or some trait correlated with stroking speed) that males perform to entice females to relax their bursal sphincter. Copyright 2002.
Piotr M Gorski - One of the best experts on this subject based on the ideXlab platform.
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Fate of Male-derived Cucurbitacins in Spotted Cucumber Beetle Females
Journal of Chemical Ecology, 2000Co-Authors: Douglas W Tallamy, Piotr M Gorski, Julia K. BurzonAbstract:Using the Spotted Cucumber Beetle, Diabrotica undecimpunctata howardi , as a model species, we begin an examination of the role of dietary cucurbitacins, the bitter tetracyclic triterpenes produced by cucurbits, in the reproductive behavior of luperine chrysomelids that seek these compounds for purposes other than host-plant recognition or nutrition. By manipulating the cucurbitacin content of adult diets, we determine: (1) how males and females partition cucurbitacins between reproductive organs and other tissues, (2) the extent to which males pass cucurbitacins to females during copulation, and (3) if females increase their cucurbitacin stores via multiple matings. After two days of exposure to dietary cucurbitacins, 8.3 times more cucurbitacins per gram dry weight were sequestered in male spermatophores than in the aggregate of remaining male tissues. These cucurbitacin-rich spermatophores were passed to females during mating, and 78.8% of the transferred cucurbitacin was deposited in eggs, 11.8% was irreversibly sequestered in other female tissues, and 9.4% was apparently excreted. Females copulated with 0–15 males prior to accepting a complete spermatophere, but did not accept measurable amounts of cucurbitacin from rejected males. Regardless of when it was received, females lost subsequent receptivity to additional males after accepting a complete spermatophore. The implications of these data are discussed in terms of sexual selection hypotheses and mating behavior in Cucumber Beetles.
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sequestered cucurbitacins and pathogenicity of metarhizium anisopliae moniliales moniliaceae on Spotted Cucumber Beetle eggs and larvae coleoptera chrysomelidae
Environmental Entomology, 1998Co-Authors: Douglas W Tallamy, Piotr M Gorski, Daryl P Whittington, Ferdinand Defurio, David A Fontaine, Peter W GothroAbstract:It has long been hypothesized that many luperine Cucumber Beetles ultimately consume and sequester highly bitter cucurbitacin triterpenes to gain protection from predators and possibly parasitoids. Here we expand this protections hypothesis to include antibiotic protection against entontopathogens. Specifically, we examine the ability of cucurbitacins sequestered in the eggs and larvae of Diabrotica undercimpunctata howardii Barber, the Spotted Cucumber Beetle, to reduce the pathogenicity of the entomopathogen Metarhizium anisopliae, Bitter and nonbitter eggs and larvae (those with and without sequestered cucurbitacin glycosides) were exposed to 0, 10 3 , 10 5 , and 10 7 M. anisopliae conidia per milliliter of distilled water. A significantly greater percentage of both eggs and larvae contining cucurbitacins survived exposure to the fungus, suggesting that the adaptive value of cucurbitacin pharmacophagy its Cucumber Beetles includes an antibiotic benefit.
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intra and interspecific genetic variation in the gustatory perception of cucurbitacins by diabroticite rootworms coleoptera chrysomelidae
Environmental Entomology, 1997Co-Authors: Douglas W Tallamy, Piotr M Gorski, John PesekAbstract:An assay designed to detect the limit of response to the phagostimulant cucurbitacin B was used to quantify intra- and interspecific variation in cucurbitacin perception in adults of the striped Cucumber Beetle, Acalymma vittatum (F.); the western corn rootworm, Diabrotica virgifera virgifera LeConte; the banded Cucumber Beetle, D. balteata LeConte; and the Spotted Cucumber Beetle, D. undecimpunctata howardi Barber. By controlling ontogenetic and environmental factors such as gender, age, reproductive status, prior consumption of cucurbitacins, and hunger, the assay was able to identify geographically based genetic differences in the mean and standard deviation of the limit of response to cucurbitacin B within and among the species tested. Possible sources of this variation and its implications for the use of cucurbitacin-based toxic baits against rootworm pests are discussed.