Sensory drive predicts that the conditions under which signaling takes place have large effects on signals, sensory systems, and behavior. The coupling of an ecological genetics approach with sen sory drive has been f...Sensory drive predicts that the conditions under which signaling takes place have large effects on signals, sensory systems, and behavior. The coupling of an ecological genetics approach with sen sory drive has been fruitful. An ecological genetics approach compares populations that experi ence different environments and asks whether population differences are adaptive and are the result of genetic and/or environmental variation. The multifaceted effects of signaling environ ments are wellexemplified by the bluefin killifish. In this system, males with blue anal fins are abundant in tanninstained swamps that lack UV/blue light but are absent in clear springs where UV/blue light is abundant. Past work indicates that lighting environments shape genetic and envir onmental variation in color patterns, visual systems, and behavior. Less is known about the select ive forces creating the across population correlations between UV/blue light and the abundance of blue males. Here, we present three new experiments that investigate the roles of lighting environ ments on male competition, female mate choice, and predation. We found strong effects of lighting environments on male competition where blue males were more likely to emerge as dominant in teastained water than in clear water. Our preliminary study on predation indicated that blue males may be less susceptible to predation in teastained water than in clear water. However, there was little evidence for female preferences favoring blue males. The resulting pattern is one where the effects of lighting environments on genetic variation and phenotypic plasticity match the direction of selection and favor the expression of blue males in swamps.展开更多
High male mating effort and high variation in female quality select for male mate choice, which may be expressed as differential investment of reproductive effort based on female value. Male reproductive effort includ...High male mating effort and high variation in female quality select for male mate choice, which may be expressed as differential investment of reproductive effort based on female value. Male reproductive effort includes investment in direct contest competition with rival males for access to females, yet variation in male-male contest behavior is rarely examined in the context of male mate choice. We examine such male response to variation in female body size, reproductive state, and female-specific ornamentation in the striped plateau lizard, Sceloporus virgatus. We housed lizards in trios of 2 size-matched males and one female for 5 days, such that all 3 lizards were physi- cally isolated and the males could see the female but not each other. We then placed males simultaneously into the female＇s cage and scored the interaction. Male-male aggression was not significantly affected by female body size, reproductive state, nor ornament color, but was influenced by ornament size which reliably signals the phenotypic quality of the female and her off- spring. In the presence of larger-ornamented females, males engaged in more male-male aggressive display behavior more quickly, and performed fewer high-intensity contact behaviors but were equally likely to escalate to this riskier level of fighting. Our data suggest that males adjust their energetic investment during intrasexual competitive interactions in response to variation in the contested female which, assuming males gain direct or indirect benefits from their strategic allocation of reproductive effort, fits the modern understanding of male mate choice.展开更多
Mating decisions can be affected by intrasexual competition and sensitive to operational sex-ratio （OSR） changes in the population. Conceptually, it is assumed that both male and female matecompetition may interfere...Mating decisions can be affected by intrasexual competition and sensitive to operational sex-ratio （OSR） changes in the population. Conceptually, it is assumed that both male and female matecompetition may interfere with female reproductive decisions. Experimentally, however, the focus has been on the effect of male competition on mate choice. In many species with paternal care as in the common goby Pomatoschistus microps, the OSR is often female-biased and female matecompetition for access to available nesting males occurs. Using the same protocol for 3 experi- ments testing the effect of a perceived risk of female mate-competition, I studied female preferences for nest-holding males differing in its nest size （large/small）, body size （large/small）, and nest status （with/without eggs already in nest） and measured mating decisions, spawning latencies, and clutch size. Regardless of the social context, females preferred males with larger nests. A preference for large males was only expressed in presence of additional females. For nest status, there was a tendency for females to prefer mating with males with an empty nest. Here, female-female competition increased the propensity to mate. The results of this study show that females are sensitive to a female competitive social environment and suggest that in choice situations, females respond to the social context mainly by mating decisions per se rather than by adjusting the clutch size or spawning latency. Females base their mating decisions not only on a male＇s nest size but also on male size as an additional cue of mate quality in the presence of additional females.展开更多
Testosterone secretion may regulate the reproductive effort and the development of sexual traits,but it may also involve costs at the immunological and metabolic levels.However,the evidence for this trade-off in wild ...Testosterone secretion may regulate the reproductive effort and the development of sexual traits,but it may also involve costs at the immunological and metabolic levels.However,the evidence for this trade-off in wild populations is scarce.Cortisol also plays an important role in mediating the reproductive and immune functions.In this study,we analyzed whether the endoparasite burden relates to hormonal levels(fecal testosterone and cortisol metabolites)and/or morphological sexual traits(size of the dark ventral patch,a trait that indicates reproductive effort in males)in male Iberian red deer.For this purpose,we sampled male red deer harvested during hunting actions in 2 types of populations in south western Spain that differed in structure,affecting the level of male–male competition for mates.We used coprological analyses to estimate the parasite burden mainly of gastrointestinal and bronchopulmonary nematodes and of protozoa,and assessed testosterone and cortisol metabolite levels from fecal pellets.We found a positive relationship of host parasitation with both testosterone levels and the size of the dark ventral patch,but these relationships depended on the intensity of male–male competition in the population,being only found under the high-competition scenario.These results are discussed under the hypothesis of the testosterone immunocompetence handicap,suggesting a cost at the immunological level,and,therefore,higher susceptibility to parasite infection in males that make a greater reproductive effort.However,this effect seems to be modulated by the social environment(male–male competition)that might lead to different optima in testosterone production and sexual trait development.展开更多
文摘Sensory drive predicts that the conditions under which signaling takes place have large effects on signals, sensory systems, and behavior. The coupling of an ecological genetics approach with sen sory drive has been fruitful. An ecological genetics approach compares populations that experi ence different environments and asks whether population differences are adaptive and are the result of genetic and/or environmental variation. The multifaceted effects of signaling environ ments are wellexemplified by the bluefin killifish. In this system, males with blue anal fins are abundant in tanninstained swamps that lack UV/blue light but are absent in clear springs where UV/blue light is abundant. Past work indicates that lighting environments shape genetic and envir onmental variation in color patterns, visual systems, and behavior. Less is known about the select ive forces creating the across population correlations between UV/blue light and the abundance of blue males. Here, we present three new experiments that investigate the roles of lighting environ ments on male competition, female mate choice, and predation. We found strong effects of lighting environments on male competition where blue males were more likely to emerge as dominant in teastained water than in clear water. Our preliminary study on predation indicated that blue males may be less susceptible to predation in teastained water than in clear water. However, there was little evidence for female preferences favoring blue males. The resulting pattern is one where the effects of lighting environments on genetic variation and phenotypic plasticity match the direction of selection and favor the expression of blue males in swamps.
文摘High male mating effort and high variation in female quality select for male mate choice, which may be expressed as differential investment of reproductive effort based on female value. Male reproductive effort includes investment in direct contest competition with rival males for access to females, yet variation in male-male contest behavior is rarely examined in the context of male mate choice. We examine such male response to variation in female body size, reproductive state, and female-specific ornamentation in the striped plateau lizard, Sceloporus virgatus. We housed lizards in trios of 2 size-matched males and one female for 5 days, such that all 3 lizards were physi- cally isolated and the males could see the female but not each other. We then placed males simultaneously into the female＇s cage and scored the interaction. Male-male aggression was not significantly affected by female body size, reproductive state, nor ornament color, but was influenced by ornament size which reliably signals the phenotypic quality of the female and her off- spring. In the presence of larger-ornamented females, males engaged in more male-male aggressive display behavior more quickly, and performed fewer high-intensity contact behaviors but were equally likely to escalate to this riskier level of fighting. Our data suggest that males adjust their energetic investment during intrasexual competitive interactions in response to variation in the contested female which, assuming males gain direct or indirect benefits from their strategic allocation of reproductive effort, fits the modern understanding of male mate choice.
文摘Mating decisions can be affected by intrasexual competition and sensitive to operational sex-ratio （OSR） changes in the population. Conceptually, it is assumed that both male and female matecompetition may interfere with female reproductive decisions. Experimentally, however, the focus has been on the effect of male competition on mate choice. In many species with paternal care as in the common goby Pomatoschistus microps, the OSR is often female-biased and female matecompetition for access to available nesting males occurs. Using the same protocol for 3 experi- ments testing the effect of a perceived risk of female mate-competition, I studied female preferences for nest-holding males differing in its nest size （large/small）, body size （large/small）, and nest status （with/without eggs already in nest） and measured mating decisions, spawning latencies, and clutch size. Regardless of the social context, females preferred males with larger nests. A preference for large males was only expressed in presence of additional females. For nest status, there was a tendency for females to prefer mating with males with an empty nest. Here, female-female competition increased the propensity to mate. The results of this study show that females are sensitive to a female competitive social environment and suggest that in choice situations, females respond to the social context mainly by mating decisions per se rather than by adjusting the clutch size or spawning latency. Females base their mating decisions not only on a male＇s nest size but also on male size as an additional cue of mate quality in the presence of additional females.
基金Financial support was received through projects CGL2013-48122-P and CGL2016-77052-P to JC.
文摘Testosterone secretion may regulate the reproductive effort and the development of sexual traits,but it may also involve costs at the immunological and metabolic levels.However,the evidence for this trade-off in wild populations is scarce.Cortisol also plays an important role in mediating the reproductive and immune functions.In this study,we analyzed whether the endoparasite burden relates to hormonal levels(fecal testosterone and cortisol metabolites)and/or morphological sexual traits(size of the dark ventral patch,a trait that indicates reproductive effort in males)in male Iberian red deer.For this purpose,we sampled male red deer harvested during hunting actions in 2 types of populations in south western Spain that differed in structure,affecting the level of male–male competition for mates.We used coprological analyses to estimate the parasite burden mainly of gastrointestinal and bronchopulmonary nematodes and of protozoa,and assessed testosterone and cortisol metabolite levels from fecal pellets.We found a positive relationship of host parasitation with both testosterone levels and the size of the dark ventral patch,but these relationships depended on the intensity of male–male competition in the population,being only found under the high-competition scenario.These results are discussed under the hypothesis of the testosterone immunocompetence handicap,suggesting a cost at the immunological level,and,therefore,higher susceptibility to parasite infection in males that make a greater reproductive effort.However,this effect seems to be modulated by the social environment(male–male competition)that might lead to different optima in testosterone production and sexual trait development.
