Klaus Reinhold - Academia.edu (original) (raw)
Papers by Klaus Reinhold
The Science of Nature
Sperm removal behaviour (SRB) is known in many animals, and male genital structures are often inv... more Sperm removal behaviour (SRB) is known in many animals, and male genital structures are often involved in the SRB, e.g. rubbing female genitalia vigorously. However, it remains unclear how those male genital structures function properly without severe genital damage during SRB. In the present study, we focused on the bushcricket Metaplastes ornatus and examined the biomechanics of male and female genital structures, involved in their SRB as a model case. During an initial phase of mating, males of this species thrust their subgenital plate with hook-like spurs and many microscopic spines into the female genital chamber. By moving the subgenital plate back-and-forth, males stimulate females, and this stimulation induces the ejection of sperm previously stored in females. We aimed to uncover the mechanics of the interaction between the subgenital plate and genital chamber during SRB. The genital morphology and its material composition were investigated using modern imaging and microsc...
1. The genus Gambusia represents approximately 45 species of polyandrous livebearing fishes with ... more 1. The genus Gambusia represents approximately 45 species of polyandrous livebearing fishes with reversed sexual size dimorphism (i.e. males smaller than females) and with copulation predominantly via male coercion. Male body size has been suggested as an important sexually selected trait, but despite abundant research, evidence for sexual selection on male body size in this genus is mixed. 2. Studies have found that large males have an advantage in both male-male competition and female choice, but that small males perform sneaky copulations better and at higher frequency and thus may sire more offspring in this coercive mating system. Here, we synthesized this discrepant body of evidence in the primary literature. 3. Using pre-registered methods and hypotheses, we performed a systematic review and meta-analysis combining published (n = 19 studies, k = 106 effect sizes) and unpublished data (n = 17, k = 242) to test whether there is overall selection on male body size across studies...
BMC Evolutionary Biology
Background: Studying reproductive trait allometries can help to understand optimal male investmen... more Background: Studying reproductive trait allometries can help to understand optimal male investment strategies under sexual selection. In promiscuous mating systems, studies across several taxa suggest that testes allometry is usually positive, presumably due to strong selection on sperm numbers through intense sperm competition. Here, we investigated testes allometry in a bush-cricket species, Metaplastes ornatus, in which females mate promiscuously, but where sperm removal behaviour by males likely drastically reduces realised sperm competition level. Results: As hypothesised, we found evidence for negative testes allometry and hence a fundamentally different male investment strategy compared to species under intense sperm competition. In addition, the mean relative testes size of M. ornatus was small compared to other species of bush-crickets. Surprisingly, the spermatophore gland, a potential alternative trait that males could invest in instead of testes, also did not show positive allometry, but was approximately isometric. We further observed the expected pattern of negative allometry for the male morphological structure responsible for sperm removal in this species, the subgenital plate, supporting the onesize-fits-all hypothesis for intromittent genitalia. Conclusion: Our findings suggest that the evolution of sperm removal behaviour in M. ornatus was a key adaptation for avoiding sperm competition, with important consequences for reproductive trait allometries. Nevertheless, they also imply that it does not pay for larger males to invest disproportionately in nuptial gift production in this species.
Meta-analyses are increasingly used in biology to both quantitatively summarize available evidenc... more Meta-analyses are increasingly used in biology to both quantitatively summarize available evidence for specific questions, and generate new hypotheses. While this powerful tool has mostly been deployed to study mean effects, there is untapped potential to study effects on (trait) variance. Here, we use a recently published dataset as a case study to show how meta-analysis of variance can provide insights into ecological and evolutionary processes. This dataset included 704 effect sizes from 89 studies, covering 56 animal species, and was originally used to test developmental stress effects on a range of traits. We found that developmental stress not only negatively affects mean trait values, but also increases trait variance, mostly in reproduction, showcasing how meta-analysis of variance can reveal previously overlooked effects. Furthermore, we show how meta-analysis of variance can be used as a tool to help meta-analysts make informed methodological decisions, even when the prima...
Evolutionary Ecology
The reason for the frequent occurrence of environmental sex determination (ESD) in reptiles is st... more The reason for the frequent occurrence of environmental sex determination (ESD) in reptiles is still not well understood, although much eort has been devoted to solving the issue. Stimulated by the occurrence of nestsite philopatry in some species, this paper examines a diploid model of the in¯uence of nest-site philopatry on the evolution of ESD. Analysis shows that nest-site philopatry can lead to ESD because the ®tnesses of sons and daughters are not in¯uenced in the same way by nest-site quality. Daughters inherit the nest site and thus bene®t more than sons from a high-quality nest site. Conversely, the ®tness of daughters at low-quality nest sites is lower compared to the ®tness of sons. Therefore, genes causing ESD can spread by causing the production of more sons at low-quality nest sites and more daughters at high-quality nest sites. Suggestions are made to test empirically whether nest-site philopatry led to the evolution of ESD.
Organisms Diversity & Evolution
... local conditions that is greater than about 10%, choice of locally adapted males is beneficia... more ... local conditions that is greater than about 10%, choice of locally adapted males is beneficial as long ... Financial support from the Deutsche Forschungsgemeinschaft (RE 1167/3-1) is gratefully acknowledged ... The evolution of polyandry: multiple mating and female fitness in insects ...
Ecology and Evolution, 2017
This is an open access article under the terms of the Creative Commons Attribution License, which... more This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Evolution, 2016
One of the major goals in speciation research is to understand which isolation mechanisms form th... more One of the major goals in speciation research is to understand which isolation mechanisms form the first barriers to gene flow. This requires examining lineages that are still in the process of divergence or incipient species. Here, we investigate the presence of behavioral and several cryptic barriers between the sympatric willow and birch host races of Lochmaea capreae. Behavioral isolation did not have any profound effect on preventing gene flow. Yet despite pairs mating indiscriminately, no offspring were produced from the heterospecific matings between birch females and willow males due to the inability of males to transfer sperm to females. We found evidence for differences in genital morphology that may contribute to failed insemination attempts during copulation. The heterospecific matings between willow females and birch males resulted in viable offspring. Yet fecundity and hatchability was remarkably reduced, which is likely the result of lower efficiency in sperm transportation and storage and lower survival of sperm in the foreign reproductive tract. Our results provide evidence for the contribution of several postmating-prezygotic barriers that predate behavioral isolation and act as primary inhibitors of gene flow in this system. This is a surprising, yet perhaps often overlooked feature of barriers acting early in sympatric speciation process.
Evolution, 2016
The fitness of hybrids might be compromised as a result of intrinsic isolation and/or because the... more The fitness of hybrids might be compromised as a result of intrinsic isolation and/or because they fall between ecological niches due to their intermediate phenotypes ("extrinsic isolation"). Here, we present data from several crosses (parental crosses, F1, F2, and backcrosses) between the two host races of Lochmaea capreae on willow and birch to test for extrinsic isolation, intrinsic isolation, and environmentally dependent genetic incompatibilities. We employed a reciprocal transplant design in which offspring were raised on either host plant and their survival was recorded until adulthood. We also applied joint-scaling analysis to determine the genetic architecture of hybrid inviability. The relative fitness of the backcrosses switched between environments; furthermore, the additive genetic-environment interaction was detected as the strongest effect in our analysis. These results provide strong evidence that divergent natural selection has played a central role in the evolution of hybrid dysfunction between host races. Joint-scaling analysis detected significant negative epistatic effects that are most evident in the poor performance of F2-hybrids on willow, indicating signs of intrinsic isolation. We did not find any evidence that genetic incompatibilities are manifested independently of environmental conditions. Our findings suggest the outcome of natural hybridization between these host races is mainly affected by extrinsic isolation and a weak contribution of intrinsic isolation.
Organisms Diversity Evolution 4, 2004
Journal of Comparative Physiology a, 2015
Animals are faced with many choices and a very important one is the choice of a mating partner. I... more Animals are faced with many choices and a very important one is the choice of a mating partner. Inter-individual differences in mating preferences have been studied for some time, but most studies focus on the location of the peak preference rather than on other aspects of preference functions. In this review, we discuss the role of variation in choosiness in inter-sexual selection. We define individual-level choosiness as the change in mating propensity in response to different stimulus signals. We illustrate general issues in estimating aspects of preference functions and discuss experimental setups for quantifying variation in choosiness with a focus on choices based on acoustic signals in insects. One important consideration is whether preferences are measured sequentially one stimulus at a time or in competitive multiple-choice setups; the suitability of these alternatives depends on the ecology of the study species. Furthermore, we discuss the usefulness of behavioural proxies for determining preference functions, which can be misleading if the proxies are not linearly related to mating propensity. Finally, we address statistical approaches, including the use of function-valued trait analysis, for studying choosiness. Most of the conclusions can be generalized beyond acoustic signals in insects and to choices in non-sexual contexts.
Journal of Heredity 93, 2002
Annals of the Entomological Society of America, 2000
Although there is often an isometric relationship between the size of nongenital parts and body s... more Although there is often an isometric relationship between the size of nongenital parts and body size, data on insects and spiders indicate that male genitalic size is only slightly inßuenced by variation in body size. Eberhard et al. (1998) interpreted the low inßuence of body size on genitalic size as evidence of stabilizing selection based on cryptic female choice. Data on this aspect of sexual selection are rare. We compared the variation in genitalic size with the variation in elytra length as an indicator for body size in the males of two mordellid beetle species, Mordellistena weisei Schilsky and M. bicoloripilosa Ermisch (Coleoptera: Mordellidae), to Þnd additional indications of stabilizing selection on genital traits. The slopes of the allometric regressions between paramere size and elytra length were Ͻ1 for left and right parameres in both species, and signiÞcantly less in three of the four comparisons. There was no signiÞcant correlation between elytra length and genitalic size in either species and the coefÞcient of variation was similar for paramere size and elytra length. Although there is no unequivocal proof for the existence of cryptic female choice, the results reinforce the evidence in favor of stabilizing selection on genitalic size.
In Smelser Nj Baltes Pb International Encyclopedia of the Social and Behavioural Sciences, 2001
Behavioral Ecology and Sociobiology, 2013
ABSTRACT Behaviors that appear to be plastic may well be determined by environmental influences d... more ABSTRACT Behaviors that appear to be plastic may well be determined by environmental influences during development. Being able to produce a wide range of variants of one kind of behavior, e.g., a very short and a very long response time to a stimulus under different environmental conditions, can be described as behavioral plasticity. How such behavioral reaction norms develop for individuals is poorly understood, but several factors are likely to play a role. We investigated what factors may affect how the risk-taking behavior of the lesser wax moth, Achroia grisella, is shaped during ontogeny. We manipulated larval density to represent the potential intensity of future competition for females in a lek of males, determined adult moths’ reaction to predator signals, and tested for plasticity in the silence response, i.e., the acoustic evasion behavior of the moths during the experiments. While we found no effect of larval density on either the probability or the duration of the silence response, 11 % of the variance in duration could be explained by differences between families, and 30 % of the variance was the result of differences between individuals. We found evidence for habituation to the predator signal, clearly indicating that the silence response is a plastic-enough trait to be adjustable to the immediate environment. These results suggest that the degree to which individuals take risks in the context of acoustic signaling depends more on the immediate context and, possibly, genetic differentiation than it is a product of adaptive developmental plasticity.
Behavioral Ecology and Sociobiology 44, Sep 30, 1998
Using literature data on reciprocal crosses I estimated the in¯uence of sex-chromosomal genes on ... more Using literature data on reciprocal crosses I estimated the in¯uence of sex-chromosomal genes on morphological and behavioral traits. To determine a special role of the sex chromosomes for sexually selected traits, I compared the estimated in¯uence of X-chromosomal genes on sexually selected traits with their estimated in¯uence on traits not under sexual selection. About one-third of the phenotypic variation in sexually selected traits is caused by X-chromosomal genes. There was, in contrast, no signi®cant in¯uence of X-chromosomal genes on traits that were classi®ed as not sexually selected. Sexually selected traits thus seem to be in¯uenced signi®cantly more by X-chromosomal genes than traits not under sexual selection. Though this dierential in¯uence of X-chromosomal genes cannot readily be explained with current theoretical knowledge, it may shed some light on X-linked hybrid sterility and on the discussion between arbitrary and good-gene models for the evolution of female choice. Key words Evolution á X chromosome á Female choice á Reciprocal crosses á Sexual selection
Genetica, 2016
Speciation in herbivorous insects has received considerable attention during the last few decades... more Speciation in herbivorous insects has received considerable attention during the last few decades. Much of this group's diversity originates from adaptive population divergence onto different host plants, which often involves the evolution of specialized patterns of host choice behaviour. Differences in host choice often translates directly into divergence in mating sites, and therefore positive assortative mating will be created which will act as a strong barrier to gene flow. In this study, we first explored whether host choice is a genetically determined trait in the sympatric willow and birch host races of the leaf feeding beetle Lochmaea capreae, or whether larval experience influences adult host choice. Once we had established that host choice is a genetically based trait we determined its genetic architecture. To achieve this, we employed a reciprocal transplant design in which offspring from pure willow and birch cross-types, F1, F2 and backcrosses were raised on each host plant and their preference was determined upon reaching adulthood. We then applied joint-scaling analysis to uncover the genetic architecture of host preference. Our results suggest that rearing host does not have a pronounced effect on adult's host choice; rather the segregation pattern implies the existence of genetic loci affecting host choice in these host races. The joint-scaling analysis revealed that population differences in host choice are mainly influenced by the contribution of additive genetic effects and also maternally inherited cytoplasmic effects. We explore the implications of our findings for evolutionary dynamics of sympatric host race formation and speciation.
Evolutionary Biology, 2015
Maintenance of genetic variance in secondary sexual traits, including bizarre ornaments and elabo... more Maintenance of genetic variance in secondary sexual traits, including bizarre ornaments and elaborated courtship displays, is a central problem of sexual selection theory. Despite theoretical arguments predicting that strong sexual selection leads to a depletion of additive genetic variance, traits associated with mating success show relatively high heritability. Here we argue that because of trade-offs associated with the production of costly epigamic traits, sexual selection is likely to lead to an increase, rather than a depletion, of genetic variance in those traits. Such trade-offs can also be expected to contribute to the maintenance of genetic variation in ecologically relevant traits with important implications for evolutionary processes, e.g. adaptation to novel environments or ecological speciation. However, if trade-offs are an important source of genetic variation in sexual traits, the magnitude of genetic variation may have little relevance for the possible genetic benefits of mate choice.
The Science of Nature
Sperm removal behaviour (SRB) is known in many animals, and male genital structures are often inv... more Sperm removal behaviour (SRB) is known in many animals, and male genital structures are often involved in the SRB, e.g. rubbing female genitalia vigorously. However, it remains unclear how those male genital structures function properly without severe genital damage during SRB. In the present study, we focused on the bushcricket Metaplastes ornatus and examined the biomechanics of male and female genital structures, involved in their SRB as a model case. During an initial phase of mating, males of this species thrust their subgenital plate with hook-like spurs and many microscopic spines into the female genital chamber. By moving the subgenital plate back-and-forth, males stimulate females, and this stimulation induces the ejection of sperm previously stored in females. We aimed to uncover the mechanics of the interaction between the subgenital plate and genital chamber during SRB. The genital morphology and its material composition were investigated using modern imaging and microsc...
1. The genus Gambusia represents approximately 45 species of polyandrous livebearing fishes with ... more 1. The genus Gambusia represents approximately 45 species of polyandrous livebearing fishes with reversed sexual size dimorphism (i.e. males smaller than females) and with copulation predominantly via male coercion. Male body size has been suggested as an important sexually selected trait, but despite abundant research, evidence for sexual selection on male body size in this genus is mixed. 2. Studies have found that large males have an advantage in both male-male competition and female choice, but that small males perform sneaky copulations better and at higher frequency and thus may sire more offspring in this coercive mating system. Here, we synthesized this discrepant body of evidence in the primary literature. 3. Using pre-registered methods and hypotheses, we performed a systematic review and meta-analysis combining published (n = 19 studies, k = 106 effect sizes) and unpublished data (n = 17, k = 242) to test whether there is overall selection on male body size across studies...
BMC Evolutionary Biology
Background: Studying reproductive trait allometries can help to understand optimal male investmen... more Background: Studying reproductive trait allometries can help to understand optimal male investment strategies under sexual selection. In promiscuous mating systems, studies across several taxa suggest that testes allometry is usually positive, presumably due to strong selection on sperm numbers through intense sperm competition. Here, we investigated testes allometry in a bush-cricket species, Metaplastes ornatus, in which females mate promiscuously, but where sperm removal behaviour by males likely drastically reduces realised sperm competition level. Results: As hypothesised, we found evidence for negative testes allometry and hence a fundamentally different male investment strategy compared to species under intense sperm competition. In addition, the mean relative testes size of M. ornatus was small compared to other species of bush-crickets. Surprisingly, the spermatophore gland, a potential alternative trait that males could invest in instead of testes, also did not show positive allometry, but was approximately isometric. We further observed the expected pattern of negative allometry for the male morphological structure responsible for sperm removal in this species, the subgenital plate, supporting the onesize-fits-all hypothesis for intromittent genitalia. Conclusion: Our findings suggest that the evolution of sperm removal behaviour in M. ornatus was a key adaptation for avoiding sperm competition, with important consequences for reproductive trait allometries. Nevertheless, they also imply that it does not pay for larger males to invest disproportionately in nuptial gift production in this species.
Meta-analyses are increasingly used in biology to both quantitatively summarize available evidenc... more Meta-analyses are increasingly used in biology to both quantitatively summarize available evidence for specific questions, and generate new hypotheses. While this powerful tool has mostly been deployed to study mean effects, there is untapped potential to study effects on (trait) variance. Here, we use a recently published dataset as a case study to show how meta-analysis of variance can provide insights into ecological and evolutionary processes. This dataset included 704 effect sizes from 89 studies, covering 56 animal species, and was originally used to test developmental stress effects on a range of traits. We found that developmental stress not only negatively affects mean trait values, but also increases trait variance, mostly in reproduction, showcasing how meta-analysis of variance can reveal previously overlooked effects. Furthermore, we show how meta-analysis of variance can be used as a tool to help meta-analysts make informed methodological decisions, even when the prima...
Evolutionary Ecology
The reason for the frequent occurrence of environmental sex determination (ESD) in reptiles is st... more The reason for the frequent occurrence of environmental sex determination (ESD) in reptiles is still not well understood, although much eort has been devoted to solving the issue. Stimulated by the occurrence of nestsite philopatry in some species, this paper examines a diploid model of the in¯uence of nest-site philopatry on the evolution of ESD. Analysis shows that nest-site philopatry can lead to ESD because the ®tnesses of sons and daughters are not in¯uenced in the same way by nest-site quality. Daughters inherit the nest site and thus bene®t more than sons from a high-quality nest site. Conversely, the ®tness of daughters at low-quality nest sites is lower compared to the ®tness of sons. Therefore, genes causing ESD can spread by causing the production of more sons at low-quality nest sites and more daughters at high-quality nest sites. Suggestions are made to test empirically whether nest-site philopatry led to the evolution of ESD.
Organisms Diversity & Evolution
... local conditions that is greater than about 10%, choice of locally adapted males is beneficia... more ... local conditions that is greater than about 10%, choice of locally adapted males is beneficial as long ... Financial support from the Deutsche Forschungsgemeinschaft (RE 1167/3-1) is gratefully acknowledged ... The evolution of polyandry: multiple mating and female fitness in insects ...
Ecology and Evolution, 2017
This is an open access article under the terms of the Creative Commons Attribution License, which... more This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Evolution, 2016
One of the major goals in speciation research is to understand which isolation mechanisms form th... more One of the major goals in speciation research is to understand which isolation mechanisms form the first barriers to gene flow. This requires examining lineages that are still in the process of divergence or incipient species. Here, we investigate the presence of behavioral and several cryptic barriers between the sympatric willow and birch host races of Lochmaea capreae. Behavioral isolation did not have any profound effect on preventing gene flow. Yet despite pairs mating indiscriminately, no offspring were produced from the heterospecific matings between birch females and willow males due to the inability of males to transfer sperm to females. We found evidence for differences in genital morphology that may contribute to failed insemination attempts during copulation. The heterospecific matings between willow females and birch males resulted in viable offspring. Yet fecundity and hatchability was remarkably reduced, which is likely the result of lower efficiency in sperm transportation and storage and lower survival of sperm in the foreign reproductive tract. Our results provide evidence for the contribution of several postmating-prezygotic barriers that predate behavioral isolation and act as primary inhibitors of gene flow in this system. This is a surprising, yet perhaps often overlooked feature of barriers acting early in sympatric speciation process.
Evolution, 2016
The fitness of hybrids might be compromised as a result of intrinsic isolation and/or because the... more The fitness of hybrids might be compromised as a result of intrinsic isolation and/or because they fall between ecological niches due to their intermediate phenotypes ("extrinsic isolation"). Here, we present data from several crosses (parental crosses, F1, F2, and backcrosses) between the two host races of Lochmaea capreae on willow and birch to test for extrinsic isolation, intrinsic isolation, and environmentally dependent genetic incompatibilities. We employed a reciprocal transplant design in which offspring were raised on either host plant and their survival was recorded until adulthood. We also applied joint-scaling analysis to determine the genetic architecture of hybrid inviability. The relative fitness of the backcrosses switched between environments; furthermore, the additive genetic-environment interaction was detected as the strongest effect in our analysis. These results provide strong evidence that divergent natural selection has played a central role in the evolution of hybrid dysfunction between host races. Joint-scaling analysis detected significant negative epistatic effects that are most evident in the poor performance of F2-hybrids on willow, indicating signs of intrinsic isolation. We did not find any evidence that genetic incompatibilities are manifested independently of environmental conditions. Our findings suggest the outcome of natural hybridization between these host races is mainly affected by extrinsic isolation and a weak contribution of intrinsic isolation.
Organisms Diversity Evolution 4, 2004
Journal of Comparative Physiology a, 2015
Animals are faced with many choices and a very important one is the choice of a mating partner. I... more Animals are faced with many choices and a very important one is the choice of a mating partner. Inter-individual differences in mating preferences have been studied for some time, but most studies focus on the location of the peak preference rather than on other aspects of preference functions. In this review, we discuss the role of variation in choosiness in inter-sexual selection. We define individual-level choosiness as the change in mating propensity in response to different stimulus signals. We illustrate general issues in estimating aspects of preference functions and discuss experimental setups for quantifying variation in choosiness with a focus on choices based on acoustic signals in insects. One important consideration is whether preferences are measured sequentially one stimulus at a time or in competitive multiple-choice setups; the suitability of these alternatives depends on the ecology of the study species. Furthermore, we discuss the usefulness of behavioural proxies for determining preference functions, which can be misleading if the proxies are not linearly related to mating propensity. Finally, we address statistical approaches, including the use of function-valued trait analysis, for studying choosiness. Most of the conclusions can be generalized beyond acoustic signals in insects and to choices in non-sexual contexts.
Journal of Heredity 93, 2002
Annals of the Entomological Society of America, 2000
Although there is often an isometric relationship between the size of nongenital parts and body s... more Although there is often an isometric relationship between the size of nongenital parts and body size, data on insects and spiders indicate that male genitalic size is only slightly inßuenced by variation in body size. Eberhard et al. (1998) interpreted the low inßuence of body size on genitalic size as evidence of stabilizing selection based on cryptic female choice. Data on this aspect of sexual selection are rare. We compared the variation in genitalic size with the variation in elytra length as an indicator for body size in the males of two mordellid beetle species, Mordellistena weisei Schilsky and M. bicoloripilosa Ermisch (Coleoptera: Mordellidae), to Þnd additional indications of stabilizing selection on genital traits. The slopes of the allometric regressions between paramere size and elytra length were Ͻ1 for left and right parameres in both species, and signiÞcantly less in three of the four comparisons. There was no signiÞcant correlation between elytra length and genitalic size in either species and the coefÞcient of variation was similar for paramere size and elytra length. Although there is no unequivocal proof for the existence of cryptic female choice, the results reinforce the evidence in favor of stabilizing selection on genitalic size.
In Smelser Nj Baltes Pb International Encyclopedia of the Social and Behavioural Sciences, 2001
Behavioral Ecology and Sociobiology, 2013
ABSTRACT Behaviors that appear to be plastic may well be determined by environmental influences d... more ABSTRACT Behaviors that appear to be plastic may well be determined by environmental influences during development. Being able to produce a wide range of variants of one kind of behavior, e.g., a very short and a very long response time to a stimulus under different environmental conditions, can be described as behavioral plasticity. How such behavioral reaction norms develop for individuals is poorly understood, but several factors are likely to play a role. We investigated what factors may affect how the risk-taking behavior of the lesser wax moth, Achroia grisella, is shaped during ontogeny. We manipulated larval density to represent the potential intensity of future competition for females in a lek of males, determined adult moths’ reaction to predator signals, and tested for plasticity in the silence response, i.e., the acoustic evasion behavior of the moths during the experiments. While we found no effect of larval density on either the probability or the duration of the silence response, 11 % of the variance in duration could be explained by differences between families, and 30 % of the variance was the result of differences between individuals. We found evidence for habituation to the predator signal, clearly indicating that the silence response is a plastic-enough trait to be adjustable to the immediate environment. These results suggest that the degree to which individuals take risks in the context of acoustic signaling depends more on the immediate context and, possibly, genetic differentiation than it is a product of adaptive developmental plasticity.
Behavioral Ecology and Sociobiology 44, Sep 30, 1998
Using literature data on reciprocal crosses I estimated the in¯uence of sex-chromosomal genes on ... more Using literature data on reciprocal crosses I estimated the in¯uence of sex-chromosomal genes on morphological and behavioral traits. To determine a special role of the sex chromosomes for sexually selected traits, I compared the estimated in¯uence of X-chromosomal genes on sexually selected traits with their estimated in¯uence on traits not under sexual selection. About one-third of the phenotypic variation in sexually selected traits is caused by X-chromosomal genes. There was, in contrast, no signi®cant in¯uence of X-chromosomal genes on traits that were classi®ed as not sexually selected. Sexually selected traits thus seem to be in¯uenced signi®cantly more by X-chromosomal genes than traits not under sexual selection. Though this dierential in¯uence of X-chromosomal genes cannot readily be explained with current theoretical knowledge, it may shed some light on X-linked hybrid sterility and on the discussion between arbitrary and good-gene models for the evolution of female choice. Key words Evolution á X chromosome á Female choice á Reciprocal crosses á Sexual selection
Genetica, 2016
Speciation in herbivorous insects has received considerable attention during the last few decades... more Speciation in herbivorous insects has received considerable attention during the last few decades. Much of this group's diversity originates from adaptive population divergence onto different host plants, which often involves the evolution of specialized patterns of host choice behaviour. Differences in host choice often translates directly into divergence in mating sites, and therefore positive assortative mating will be created which will act as a strong barrier to gene flow. In this study, we first explored whether host choice is a genetically determined trait in the sympatric willow and birch host races of the leaf feeding beetle Lochmaea capreae, or whether larval experience influences adult host choice. Once we had established that host choice is a genetically based trait we determined its genetic architecture. To achieve this, we employed a reciprocal transplant design in which offspring from pure willow and birch cross-types, F1, F2 and backcrosses were raised on each host plant and their preference was determined upon reaching adulthood. We then applied joint-scaling analysis to uncover the genetic architecture of host preference. Our results suggest that rearing host does not have a pronounced effect on adult's host choice; rather the segregation pattern implies the existence of genetic loci affecting host choice in these host races. The joint-scaling analysis revealed that population differences in host choice are mainly influenced by the contribution of additive genetic effects and also maternally inherited cytoplasmic effects. We explore the implications of our findings for evolutionary dynamics of sympatric host race formation and speciation.
Evolutionary Biology, 2015
Maintenance of genetic variance in secondary sexual traits, including bizarre ornaments and elabo... more Maintenance of genetic variance in secondary sexual traits, including bizarre ornaments and elaborated courtship displays, is a central problem of sexual selection theory. Despite theoretical arguments predicting that strong sexual selection leads to a depletion of additive genetic variance, traits associated with mating success show relatively high heritability. Here we argue that because of trade-offs associated with the production of costly epigamic traits, sexual selection is likely to lead to an increase, rather than a depletion, of genetic variance in those traits. Such trade-offs can also be expected to contribute to the maintenance of genetic variation in ecologically relevant traits with important implications for evolutionary processes, e.g. adaptation to novel environments or ecological speciation. However, if trade-offs are an important source of genetic variation in sexual traits, the magnitude of genetic variation may have little relevance for the possible genetic benefits of mate choice.