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Takahisa Miyatake - One of the best experts on this subject based on the ideXlab platform.
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independence of genetic variation between circadian rhythm and development time in the seed beetle Callosobruchus Chinensis
Journal of Insect Physiology, 2011Co-Authors: Tomohiro Harano, Takahisa MiyatakeAbstract:A positive genetic correlation between periods of circadian rhythm and developmental time supports the hypothesis that circadian clocks are implicated in the timing of development. Empirical evidence for this genetic correlation in insects has been documented in two fly species. In contrast, here we show that there is no evidence of genetic correlation between circadian rhythm and development time in the adzuki bean beetle, Callosobruchus Chinensis. This species has variation that is explained by a major gene in the expression and period length of circadian rhythm between strains. In this study, we found genetic variation in development time between the strains. The development time was not covaried with either the incidence or the period length of circadian rhythm among the strains. Crosses between strains suggest that development time is controlled by a polygene. In the F(2) individuals from the crosses, the circadian rhythm is attributable to allelic variation in the major gene. Across the F(2) individuals, development time was not correlated with either the expression or the period length of circadian rhythm. Thus, we found no effects of major genes responsible for variation in the circadian rhythm on development time in C. Chinensis. Our findings collectively give no support to the hypothesis that the circadian clock is involved in the regulation of development time in this species.
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effects of temperature on mating duration sperm transfer and remating frequency in Callosobruchus Chinensis
Journal of Insect Physiology, 2009Co-Authors: Masako Katsuki, Takahisa MiyatakeAbstract:Insect body temperature is usually determined by ambient temperature. Therefore, most biochemical and physiological processes underlying behavioural patterns are temperature dependent. Mating duration is also dependent on temperature, and therefore temperature should influence on sperm transfer and female remating frequency. In the adzuki bean beetle, Callosobruchus Chinensis, we found negative relationships between ambient temperature and mating duration, sperm transfer and sperm transfer duration. Female remating frequency at lower temperature (17 degrees C) was lower than at other temperatures (25 degrees C and 33 degrees C). The physiological and behavioural significance of these results is discussed. The number of ejaculated sperm was significantly lower at 33 degrees C than at 17 degrees C; the effect of temperature on sperm transfer is discussed in relation to the intensity of female refusal behaviour directed against males.
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bidirectional selection for female propensity to remate in the bean beetle Callosobruchus Chinensis
Population Ecology, 2009Co-Authors: Tomohiro Harano, Takahisa MiyatakeAbstract:The evolution of female multiple mating, or polyandry, is difficult to comprehend and thus has been the subject of a large number of studies. However, there is only a little evidence for genetic variation in polyandry, although the evolution of a trait via selection requires genetic variation that enables the trait to respond to selection. We carried out artificial selection for increased and decreased female propensity to remate as a measure of polyandry to investigate whether this trait has a genetic component that can respond to selection in the adzuki bean beetle, Callosobruchus Chinensis. Artificial selection produced responses in both directions and divergence between the selection lines in the female propensity to remate. Although the experimental design adopted in this study selected jointly for female receptivity to remating, which is a trait of females, and male ability to inhibit female remating—both of which are associated with female propensity to remate—the observed response to selection was attributable only to the female receptivity to remating. This study indicates that the female receptivity to remating has significant additive genetic variation and can evolve according to whether remating is advantageous or disadvantageous to females in C. Chinensis.
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Positive genetic correlations between life-history traits and death-feigning behavior in adzuki bean beetle (Callosobruchus Chinensis)
Evolutionary Ecology, 2008Co-Authors: Satoshi Nakayama, Takahisa MiyatakeAbstract:Usually, several traits in organisms are genetically linked with each other; thus, correlated responses to selection are generally observed. Anti-predator behaviors may be genetically correlated with other traits such as life-history. We compared the life-history traits of individuals derived from two regimes artificially selected for the duration of death feigning in the adzuki bean beetle, Callosobruchus Chinensis . The two-way selected regimes include the L-lines with stronger intensity (longer duration and higher frequency) and the S-lines with weaker intensity (shorter duration and lower frequency) of death feigning. L-lines exhibited greater longevity, higher rates of emergence, laid bigger eggs and greater reproductive effort, and also had a tendency of faster development. Fecundity was not significantly different between L- and S-lines. These results provide the novel possibility that death feigning is a potentially advantageous anti-predator behavior that, through a positive genetic correlation with some life-history traits, can bring a higher fitness to an individual adopting this behavior. This novel aspect might explain why death-feigning behavior is prevalent in various taxonomic animal groups.
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Strategic ejaculation and level of polyandry in Callosobruchus Chinensis (Coleoptera: Bruchidae)
Journal of Ethology, 2008Co-Authors: Takashi Yamane, Takahisa MiyatakeAbstract:Variation in the level of polyandry of females produces a difference in the risk of sperm competition among males. As a consequence, investment in ejaculate expenditure by males should vary. We compared the number of sperm ejaculated by males into the female reproductive organ of six strains of the adzuki bean beetle, Callosobruchus Chinensis (Coleoptera: Bruchidae), when males were reared at different larval densities in a bean. A significant positive correlation was found between the remating frequency of females and the ratio of the ejaculate sizes of high-density and low-density males as a measure of the response to the risk of sperm competition among males. The measure was estimated by dividing the number of sperm ejaculated by males reared at high larval density in a bean with the number of sperm ejaculated by males reared alone. The number of sperm transferred by a male to a female was not correlated with the duration of copulation. The results suggest an evolutionary relationship between ejaculatory expenditure and the level of polyandry in C. Chinensis .
Tomohiro Harano - One of the best experts on this subject based on the ideXlab platform.
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water availability affects female remating in the seed beetle Callosobruchus Chinensis
Ethology, 2012Co-Authors: Tomohiro HaranoAbstract:Benefits of multiple mating to females may come from the acquisition of water in male ejaculates. This hypothesis seems plausible in species in which males provide females with large ejaculates and has been tested with the prediction that females mate more frequently when an external source of water is unavailable. My study observed that females deprived of water were more likely to remate than females given water in the adzuki bean beetle, Callosobruchus Chinensis. This result suggests that females may absorb the water in male ejaculates and thus change their remating receptivity according to the need for additional water. However, compared with related species, the ejaculate size is smaller, so ejaculatory hydration benefits are expected to be small in this species. There were no significant differences in lifetime fecundity and longevity between females that were allowed to receive one ejaculate from remating and females that were not allowed to do so when water was unavailable. This provides no evidence that receiving an additional ejaculate enhances female fitness. Thus, obtaining water from male ejaculates may partly compensate the costs of remating to females, although it alone would be insufficient to explain polyandry in C. Chinensis. Increased mating frequency in water-deprived females would not necessarily support the hypothesis that females remate for ejaculatory hydration benefits.
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female seed beetles Callosobruchus Chinensis remate more readily after mating with relatives
Animal Behaviour, 2012Co-Authors: Tomohiro Harano, Masako KatsukiAbstract:Mate relatedness can have an impact on fitness and inbreeding avoidance is a potential factor shaping mating behaviour. When females are unable to avoid mating with kin, they may exploit postcopulatory mechanisms as an alternative means to avoid inbreeding. If females increase their remating propensity after incestuous matings, they could reduce the likelihood of kin siring their offspring. We investigated the effects of male relatedness on the probabilities of female first mating and remating in the adzuki bean beetle, Callosobruchus Chinensis. Females showed no precopulatory discrimination against brothers at their first or second mating. In contrast, females mated first with brothers were more willing to remate than females mated first with unrelated males. We found no evidence that males transfer fewer sperm when mating with sisters. This study suggests that C. Chinensis does not avoid inbreeding before and during copulation. Instead, females that mated with related males adapted their subsequent mating behaviour to avoid the potential costs of inbreeding. Polyandry in this species may be the result of females attempting to prevent genetic incompatibility by remating after having mated to a relative.
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inbreeding depression in development survival and reproduction in the adzuki bean beetle Callosobruchus Chinensis
Ecological Research, 2011Co-Authors: Tomohiro HaranoAbstract:Inbreeding depression of an aspect of fitness is observed in many insects, but the traits that are of importance for inbreeding depression of fitness remain poorly understood. Here the magnitude of inbreeding depression of fitness-related traits in the development and adult stages was measured in a captive population of the adzuki bean beetle, Callosobruchus Chinensis (Coleoptera: Bruchidae). Beetles produced by full-sib matings had 8% lower survival in the development stage than did beetles produced by unrelated matings. Although inbred and outbred offspring did not differ in body size after emergence, inbred offspring took 2–3% longer to develop to emergence. This indicates inbreeding depression of growth rate. At the adult stage, inbreeding had no significant effect on longevity, however lifetime offspring production was reduced by 11%. Thus, the magnitude of inbreeding depression was relatively large for offspring production. This suggests inbreeding depression of fitness manifests, to a particularly significant extent, in reduced productivity. This study shows the C. Chinensis population, which has been in captivity for more than 100 generations, harbors genetic loads.
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independence of genetic variation between circadian rhythm and development time in the seed beetle Callosobruchus Chinensis
Journal of Insect Physiology, 2011Co-Authors: Tomohiro Harano, Takahisa MiyatakeAbstract:A positive genetic correlation between periods of circadian rhythm and developmental time supports the hypothesis that circadian clocks are implicated in the timing of development. Empirical evidence for this genetic correlation in insects has been documented in two fly species. In contrast, here we show that there is no evidence of genetic correlation between circadian rhythm and development time in the adzuki bean beetle, Callosobruchus Chinensis. This species has variation that is explained by a major gene in the expression and period length of circadian rhythm between strains. In this study, we found genetic variation in development time between the strains. The development time was not covaried with either the incidence or the period length of circadian rhythm among the strains. Crosses between strains suggest that development time is controlled by a polygene. In the F(2) individuals from the crosses, the circadian rhythm is attributable to allelic variation in the major gene. Across the F(2) individuals, development time was not correlated with either the expression or the period length of circadian rhythm. Thus, we found no effects of major genes responsible for variation in the circadian rhythm on development time in C. Chinensis. Our findings collectively give no support to the hypothesis that the circadian clock is involved in the regulation of development time in this species.
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bidirectional selection for female propensity to remate in the bean beetle Callosobruchus Chinensis
Population Ecology, 2009Co-Authors: Tomohiro Harano, Takahisa MiyatakeAbstract:The evolution of female multiple mating, or polyandry, is difficult to comprehend and thus has been the subject of a large number of studies. However, there is only a little evidence for genetic variation in polyandry, although the evolution of a trait via selection requires genetic variation that enables the trait to respond to selection. We carried out artificial selection for increased and decreased female propensity to remate as a measure of polyandry to investigate whether this trait has a genetic component that can respond to selection in the adzuki bean beetle, Callosobruchus Chinensis. Artificial selection produced responses in both directions and divergence between the selection lines in the female propensity to remate. Although the experimental design adopted in this study selected jointly for female receptivity to remating, which is a trait of females, and male ability to inhibit female remating—both of which are associated with female propensity to remate—the observed response to selection was attributable only to the female receptivity to remating. This study indicates that the female receptivity to remating has significant additive genetic variation and can evolve according to whether remating is advantageous or disadvantageous to females in C. Chinensis.
Midori Tuda - One of the best experts on this subject based on the ideXlab platform.
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adaptive egg size plasticity for larval competition and its limits in the seed beetle Callosobruchus Chinensis
Entomologia Experimentalis Et Applicata, 2013Co-Authors: Shin Ichi Yanagi, Yoriko Saeki, Midori TudaAbstract:Life-history theory predicts that females who experienced stressful conditions, such as larval competition or malnutrition, should increase their investment in individual offspring to increase offspring fitness (the adaptive parental hypothesis). In contrast, it has been shown that when females were reared under stressful conditions, they become smaller, which consequently decreases egg size (the parental stress hypothesis). To test whether females adjust their egg volume depending on larval competition, independent of maternal body mass constraint, we used a pest species of stored adzuki beans, Callosobruchus Chinensis (L.) (Coleoptera: Chrysomelidae: Bruchinae). The eggs of females reared with competitors were smaller than those of females reared alone, supporting the parental stress hypothesis; however, correcting for female body size, females reared with competitors produced larger eggs than those reared in the absence of competition, supporting the adaptive parental hypothesis, as predicted. The phenotypic plasticity in females' investment in each offspring in stressful environments counteracts the constraint of body size on egg size.
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female size constrains egg size via the influence of reproductive organ size and resource storage in the seed beetle Callosobruchus Chinensis
Journal of Insect Physiology, 2012Co-Authors: Shin Ichi Yanagi, Midori TudaAbstract:The standard egg size model predicts that a mother lays an optimal size of eggs in a given environment. However, there is evidence that larger females lay larger eggs across diverse animal taxa. This positive correlation suggests there are morphological constraints on egg size imposed by the size of the maternal organ through which eggs pass during oviposition. There is also evidence that large mothers that have greater capital resources produce large eggs. We tested whether morphological (ovipositor width) or physiological (maternal body weight as a measure of capital resources) mechanisms constrain egg size, using an inbred line of seed beetles, Callosobruchus Chinensis. In addition, we tested whether having a wide ovipositor relative to body size is costly in terms of egg production. Egg width but not length increased with ovipositor width. Egg length and width increased with body weight. The cost of wider ovipositor was not detected. We conclude that females adjust egg size depending on capital resource level under the morphological constraint.
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interaction effect among maternal environment maternal investment and progeny genotype on life history traits in Callosobruchus Chinensis
Functional Ecology, 2010Co-Authors: Shin Ichi Yanagi, Midori TudaAbstract:Summary 1. Transgenerational effects, genetic or non-genetic, affect population dynamics and the evolution of life-history traits. Besides genetic components, the size of gametes (eggs and seeds), simultaneously a parental and progeny character, can mediate environmental condition experienced by a parent. In both animals and arthropods, mothers are known to reduce their egg mass depending on their malcondition. 2. Progeny may also modify their life history traits to increase their own fitness when constrained by maternal investment, which may eventually nullify transgenerational effects on population dynamics and evolution. Such fitness modification by the progeny under new environmental conditions requires phenotypic plasticity interacting with egg mass. We hypothesize that different selective environments should produce inter-population genetic diversification of the response to maternal investment on each egg, which would be detected as a paternal genotype × environment × previous (i.e. maternal) environment (G × E × preE) interaction in progeny fitness. 3. To evaluate the contribution of maternal non-genetic resource and the genetic component separately, we used an inbred-isofemale-line approach to eliminate the influence of the genetic correlation between egg mass and other life history traits, in the adzuki bean beetle, Callosobruchus Chinensis. The females were reared at either high or low densities to generate variability in egg resources. To test the additive or interactive effect of genotype, non-genetic egg resources, and maternal environment on the life history traits of the progeny, they were crossed with males from laboratory and wild strains that had been subjected to different levels of population density. 4. The G × E × preE interaction effect was detected on the correlation structure between egg mass and development time: In the offspring of mothers reared at low density, the negative correlation between egg mass and development time was higher with lab strain fathers, whereas in the offspring of mothers reared at high density, the negative correlation was higher with the wild strain fathers. 5. Our results indicate a genetic difference in the response of development time but not of adult mass to environmental variation in egg mass. Such density-dependent enhancement of maternal effects may destabilize population dynamics and accelerate evolution.
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habitat related mtdna polymorphism in the stored bean pest Callosobruchus Chinensis coleoptera bruchidae
Bulletin of Entomological Research, 2004Co-Authors: Midori Tuda, Natsuko Kondo, Naoya Wasano, Shwu Bin Horng, L Y Chou, Yoichi TateishiAbstract:The genetic diversity of populations of the azuki bean beetle, Callosobruchus Chinensis (Linnaeus) from natural, pre-harvest and post-harvest sites, was investigated to understand population structure and gene flow. A 522-bp fragment of the mitochondrial gene COI was sequenced for eight populations of C. Chinensisfrom Japan, Korea and Taiwan collected from different habitats. Six haplotypes were detected, one of which, U1, occurred most frequently and widely. The following hypotheses were tested as a cause of the wide distribution of haplotype U1; (i) topographical separation (by national boundaries), (ii) host plant species, and (iii) habitat type (natural, pre-harvest crop, or post-harvest storage). Categorization of collection sites by country or by host species did not yield differences in the occurrence of haplotype U1, but habitat type did. Populations utilizing cultivated post-harvest hosts that were mass stored were highly likely to be the common haplotype, whereas host plants in natural habitats away from agriculture were utilized by populations with locally characteristic haplotypes. Sampling of commercial beans for quarantine and export purposes indicated that gene flow in C. Chinensis was largely unidirectional into Japan at the present time.
Shin Ichi Yanagi - One of the best experts on this subject based on the ideXlab platform.
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adaptive egg size plasticity for larval competition and its limits in the seed beetle Callosobruchus Chinensis
Entomologia Experimentalis Et Applicata, 2013Co-Authors: Shin Ichi Yanagi, Yoriko Saeki, Midori TudaAbstract:Life-history theory predicts that females who experienced stressful conditions, such as larval competition or malnutrition, should increase their investment in individual offspring to increase offspring fitness (the adaptive parental hypothesis). In contrast, it has been shown that when females were reared under stressful conditions, they become smaller, which consequently decreases egg size (the parental stress hypothesis). To test whether females adjust their egg volume depending on larval competition, independent of maternal body mass constraint, we used a pest species of stored adzuki beans, Callosobruchus Chinensis (L.) (Coleoptera: Chrysomelidae: Bruchinae). The eggs of females reared with competitors were smaller than those of females reared alone, supporting the parental stress hypothesis; however, correcting for female body size, females reared with competitors produced larger eggs than those reared in the absence of competition, supporting the adaptive parental hypothesis, as predicted. The phenotypic plasticity in females' investment in each offspring in stressful environments counteracts the constraint of body size on egg size.
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female size constrains egg size via the influence of reproductive organ size and resource storage in the seed beetle Callosobruchus Chinensis
Journal of Insect Physiology, 2012Co-Authors: Shin Ichi Yanagi, Midori TudaAbstract:The standard egg size model predicts that a mother lays an optimal size of eggs in a given environment. However, there is evidence that larger females lay larger eggs across diverse animal taxa. This positive correlation suggests there are morphological constraints on egg size imposed by the size of the maternal organ through which eggs pass during oviposition. There is also evidence that large mothers that have greater capital resources produce large eggs. We tested whether morphological (ovipositor width) or physiological (maternal body weight as a measure of capital resources) mechanisms constrain egg size, using an inbred line of seed beetles, Callosobruchus Chinensis. In addition, we tested whether having a wide ovipositor relative to body size is costly in terms of egg production. Egg width but not length increased with ovipositor width. Egg length and width increased with body weight. The cost of wider ovipositor was not detected. We conclude that females adjust egg size depending on capital resource level under the morphological constraint.
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interaction effect among maternal environment maternal investment and progeny genotype on life history traits in Callosobruchus Chinensis
Functional Ecology, 2010Co-Authors: Shin Ichi Yanagi, Midori TudaAbstract:Summary 1. Transgenerational effects, genetic or non-genetic, affect population dynamics and the evolution of life-history traits. Besides genetic components, the size of gametes (eggs and seeds), simultaneously a parental and progeny character, can mediate environmental condition experienced by a parent. In both animals and arthropods, mothers are known to reduce their egg mass depending on their malcondition. 2. Progeny may also modify their life history traits to increase their own fitness when constrained by maternal investment, which may eventually nullify transgenerational effects on population dynamics and evolution. Such fitness modification by the progeny under new environmental conditions requires phenotypic plasticity interacting with egg mass. We hypothesize that different selective environments should produce inter-population genetic diversification of the response to maternal investment on each egg, which would be detected as a paternal genotype × environment × previous (i.e. maternal) environment (G × E × preE) interaction in progeny fitness. 3. To evaluate the contribution of maternal non-genetic resource and the genetic component separately, we used an inbred-isofemale-line approach to eliminate the influence of the genetic correlation between egg mass and other life history traits, in the adzuki bean beetle, Callosobruchus Chinensis. The females were reared at either high or low densities to generate variability in egg resources. To test the additive or interactive effect of genotype, non-genetic egg resources, and maternal environment on the life history traits of the progeny, they were crossed with males from laboratory and wild strains that had been subjected to different levels of population density. 4. The G × E × preE interaction effect was detected on the correlation structure between egg mass and development time: In the offspring of mothers reared at low density, the negative correlation between egg mass and development time was higher with lab strain fathers, whereas in the offspring of mothers reared at high density, the negative correlation was higher with the wild strain fathers. 5. Our results indicate a genetic difference in the response of development time but not of adult mass to environmental variation in egg mass. Such density-dependent enhancement of maternal effects may destabilize population dynamics and accelerate evolution.
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costs of mating and egg production in female Callosobruchus Chinensis
Journal of Insect Physiology, 2003Co-Authors: Shin Ichi Yanagi, Takahisa MiyatakeAbstract:Costs of reproduction include the costs of mating and egg production. Specific techniques such as irradiation or genetic mutation have been used to divide the expense into costs of mating and egg production in previous studies. We tried to divide the costs in the adzuki bean beetle, Callosobruchus Chinensis (Coleoptera: Bruchidae), which needs some kinds of bean as an oviposition substrate. Mated females that were not allowed to lay eggs had a shorter life span than virgin females, but they had a longer life span than mated females that were allowed to lay eggs. The results showed two independent significant costs, mating and egg production, on the life span in C. Chinensis. Costs of mating, however, include the costs of sexual harassment by males and copulation itself, and we need further studies to divide the costs. The present method for dividing the cost of reproduction into costs of mating and egg production can be applied to a broad taxonomic range of insect species, and thus it will be a useful model system for inter-specific comparisons of costs of mating and egg production.
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effects of maternal age on reproductive traits and fitness components of the offspring in the bruchid beetle Callosobruchus Chinensis coleoptera bruchidae
Physiological Entomology, 2002Co-Authors: Shin Ichi Yanagi, Takahisa MiyatakeAbstract:In many insect species, the size and number of eggs decrease with maternal age. Thus, both the size and number of eggs must be considered to know the exact cost of reproduction with maternal age. The resource depletion hypothesis was examined in the bruchid beetle Callosobruchus Chinensis. The hypothesis explains why the egg size decreases with maternal age based on the decline of the female's reproductive capacity. A decrease was found in reproductive effort (= egg size x the number of eggs) and the fitness component of offspring with maternal age. The effects of the female's nutritional status on the relationship between maternal age and the reproductive effort of females with and without food and water were also examined. The results indicate that the decrease in size and number of eggs with maternal age can be explained by the resource depletion hypothesis in C. Chinensis.
Masako Katsuki - One of the best experts on this subject based on the ideXlab platform.
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female seed beetles Callosobruchus Chinensis remate more readily after mating with relatives
Animal Behaviour, 2012Co-Authors: Tomohiro Harano, Masako KatsukiAbstract:Mate relatedness can have an impact on fitness and inbreeding avoidance is a potential factor shaping mating behaviour. When females are unable to avoid mating with kin, they may exploit postcopulatory mechanisms as an alternative means to avoid inbreeding. If females increase their remating propensity after incestuous matings, they could reduce the likelihood of kin siring their offspring. We investigated the effects of male relatedness on the probabilities of female first mating and remating in the adzuki bean beetle, Callosobruchus Chinensis. Females showed no precopulatory discrimination against brothers at their first or second mating. In contrast, females mated first with brothers were more willing to remate than females mated first with unrelated males. We found no evidence that males transfer fewer sperm when mating with sisters. This study suggests that C. Chinensis does not avoid inbreeding before and during copulation. Instead, females that mated with related males adapted their subsequent mating behaviour to avoid the potential costs of inbreeding. Polyandry in this species may be the result of females attempting to prevent genetic incompatibility by remating after having mated to a relative.
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effects of temperature on mating duration sperm transfer and remating frequency in Callosobruchus Chinensis
Journal of Insect Physiology, 2009Co-Authors: Masako Katsuki, Takahisa MiyatakeAbstract:Insect body temperature is usually determined by ambient temperature. Therefore, most biochemical and physiological processes underlying behavioural patterns are temperature dependent. Mating duration is also dependent on temperature, and therefore temperature should influence on sperm transfer and female remating frequency. In the adzuki bean beetle, Callosobruchus Chinensis, we found negative relationships between ambient temperature and mating duration, sperm transfer and sperm transfer duration. Female remating frequency at lower temperature (17 degrees C) was lower than at other temperatures (25 degrees C and 33 degrees C). The physiological and behavioural significance of these results is discussed. The number of ejaculated sperm was significantly lower at 33 degrees C than at 17 degrees C; the effect of temperature on sperm transfer is discussed in relation to the intensity of female refusal behaviour directed against males.
