In hermaphroditic plants, female reproductive success often varies among different positions within an inflorescence. However, few studies have evaluated the relative importance of underlying causes such as pollen lim...In hermaphroditic plants, female reproductive success often varies among different positions within an inflorescence. However, few studies have evaluated the relative importance of underlying causes such as pollen limitation, resource limitation or architectural effect, and few have compared male allocation. During a 2-year investigation, we found that female reproductive success of an acropetally flowering species, Corydalis remota Fisch. ex Maxim. var. lineariloba Maxim. was significantly lower in the upper late developing flowers when compared with the lower early flowers. Supplementation with outcross pollen did not improve female reproductive success of the upper flowers, while removal of the lower developing fruits significantly increased female reproductive success of the upper flowers in both years, evidencing resource limitation of the upper flowers. Female production in upper flowers was greatly improved by simultaneous pollen supplementation of the upper flowers and removal of the lower fruits, suggesting that, when resources are abundant, pollen may limit the female reproductive success of the upper flowers. The less seed mass in the upper flowers didn＇t increase in all treatments due to architecture. In the upper flowers, ovule production was significantly lower and the pollen ： ovule ratio was significantly higher. These results suggest that male-biased sex allocation in the upper flowers may lead to increased male reproductive success, whereas the lower flowers have higher female reproductive success.展开更多
Population structure determines individuals’interactions and trade-offs with evolutionary consequences.Male-biased populations increase intrasexual competition and intersexual harassment,reducing female resource acqu...Population structure determines individuals’interactions and trade-offs with evolutionary consequences.Male-biased populations increase intrasexual competition and intersexual harassment,reducing female resource acquisition,and thus,resources availability for the following generation.We analyzed direct and cross-generational effects of male harassment in two generations of damselflies(Odonata).We exposed adult females to treatments with different sex-ratio and density(balanced and male-biased)to modify the male harassment level.We analyzed female fecundity,fertility,and number of faecal deposits as an indirect measure of resources acquisition.We studied female flight performance after repeated exposures to males.We analyzed survivorship,development,exploration,thigmotaxis,and feeding latency of larvae produced by the experimental females.In both generations,we analyzed four metrics of behavior:mean value,interindividual differences in plasticity,intra-individual unpredictability,and repeatability.Mating duration increased in male-biased treatment,whereas female resources acquisition and fertility decreased.Females that mated longer showed higher fecundity when they were exposed to balanced treatment,but not if they were exposed to male-biased treatment.Females from the male-biased treatment showed interindividual differences in plasticity and no repeatability in flight performance.Offspring showed balanced sex-ratio and similar survivorship,development,and feeding latency independently of the parental treatment;however,females exposed to male-biased treatment produced offspring with higher differences in exploration plasticity and daughters less explorative and with higher unpredictable thigmotaxis.We propose prolonged copulation as courtship at balanced sex-ratio but a cost to females under male-biased sex-ratio.Cross-generational effects in behavioral variability may be a mechanism to cope with predicted future environments.展开更多
One of the factors facilitating the expansion and proliferation of wild boar Sus scrofa is the plasticity of its reproductive biology.Nevertheless,the real influence of maternal and environmental factors on number and...One of the factors facilitating the expansion and proliferation of wild boar Sus scrofa is the plasticity of its reproductive biology.Nevertheless,the real influence of maternal and environmental factors on number and sex of the offspring is stll controversial.While the litter size was shown to be related with the maternal condition,the strength of this relation remains to be understood,together with the possible role played by environmental conditions.Analogously,it is unclear whether wild boar females can adjust their offspring sex.We investigated multiple aspects of wild boar maternal investment by means of a 10-year dataset of female reproductive traits and a set of biologically meaningful environmental variables.The maternal condition slightly affected the litter size but not the offspring sex,and environment did not affect the litter size or the offspring sex.Moreover,mothers did not cope with the higher costs entailed by producing sons by placing them in the most advantageous intrauterine position,nor by allocating less resources on daughters.Our set of results showed that the female reproductive investment is quite rigid in comparison with other aspects of wild boar reproductive biology.Wild boar females seem to adopt a typical rstrategy,producing constantly large litters and allocating resources on both sexes regardless of internal and external conditions.Such strategy may be adaptive to cope with environmental unpredictability and an intense human harvest,contributing to explain the extreme success of wild boar within human-dominated landscapes.展开更多
Aims sex allocation in plants is often plastic,enabling individuals to adjust to variable environments.However,the predicted male-biased sex allocation in response to low resource conditions has rarely been experiment...Aims sex allocation in plants is often plastic,enabling individuals to adjust to variable environments.However,the predicted male-biased sex allocation in response to low resource conditions has rarely been experimentally tested in hermaphroditic plants.in particular,it is unknown whether distal flowers in linear inflorescences show a larger shift to male allocation relative to basal flowers when resources are reduced.in this study,we measure position-depend-ent plasticity of floral sex allocation within racemes of Aconitum gymnandrum in response to reduced resource availability.Methods using a defoliation treatment in the field applied to potted plants from a nested half-sibling design,we examined the effects of the treatment,flower position,family and their interactions.Important Findingsallocation to male function increased with more distal flower posi-tion,while female allocation either did not change with position or declined at the most distal flowers.Defoliation significantly reduced the mass of both the androecium and gynoecium,but not anther number or carpel number.gynoecial mass declined more strongly with defoliation than did androecial mass,resulting in a significant increase in the androecium/gynoecium ratio as predicted by sex allocation theory.Plastic responses of androecium mass and gynoecium mass were affected by flower position,with less mass lost in basal flowers,but similar plastic magnitude in both sexual traits across flower position lead to consistent variation in the androecium/gynoecium ratio along the inflorescence.a sig-nificant treatment*paternal family interaction for the androecium/gynoecium ratio is evidence for additive genetic variation for plastic floral sex allocation,which means that further evolution of alloca-tion can occur.展开更多
基金Supported by the National Natural Science Foundation of China (30430160).
文摘In hermaphroditic plants, female reproductive success often varies among different positions within an inflorescence. However, few studies have evaluated the relative importance of underlying causes such as pollen limitation, resource limitation or architectural effect, and few have compared male allocation. During a 2-year investigation, we found that female reproductive success of an acropetally flowering species, Corydalis remota Fisch. ex Maxim. var. lineariloba Maxim. was significantly lower in the upper late developing flowers when compared with the lower early flowers. Supplementation with outcross pollen did not improve female reproductive success of the upper flowers, while removal of the lower developing fruits significantly increased female reproductive success of the upper flowers in both years, evidencing resource limitation of the upper flowers. Female production in upper flowers was greatly improved by simultaneous pollen supplementation of the upper flowers and removal of the lower fruits, suggesting that, when resources are abundant, pollen may limit the female reproductive success of the upper flowers. The less seed mass in the upper flowers didn＇t increase in all treatments due to architecture. In the upper flowers, ovule production was significantly lower and the pollen ： ovule ratio was significantly higher. These results suggest that male-biased sex allocation in the upper flowers may lead to increased male reproductive success, whereas the lower flowers have higher female reproductive success.
基金I.S.V.was funded by a postdoctoral fellowship of the Galician government(Xunta de GaliciaAxudas de apoio a etapa posdoutoral 2017+4 种基金ref:ED481B-2017/034)X.Y.was funded by the State Scholarship Fund(file No.201908500062)of China Scholarship CouncilA.C.R.was funded by grant PGC2018-096656-B-100 from MCIN/AEI/10.13039/501100011033(Agencia Estatal de InvestigacionMinisterio de Ciencia e Innovacion)from"ERDF A way of making Europe,"by the"European Union."。
文摘Population structure determines individuals’interactions and trade-offs with evolutionary consequences.Male-biased populations increase intrasexual competition and intersexual harassment,reducing female resource acquisition,and thus,resources availability for the following generation.We analyzed direct and cross-generational effects of male harassment in two generations of damselflies(Odonata).We exposed adult females to treatments with different sex-ratio and density(balanced and male-biased)to modify the male harassment level.We analyzed female fecundity,fertility,and number of faecal deposits as an indirect measure of resources acquisition.We studied female flight performance after repeated exposures to males.We analyzed survivorship,development,exploration,thigmotaxis,and feeding latency of larvae produced by the experimental females.In both generations,we analyzed four metrics of behavior:mean value,interindividual differences in plasticity,intra-individual unpredictability,and repeatability.Mating duration increased in male-biased treatment,whereas female resources acquisition and fertility decreased.Females that mated longer showed higher fecundity when they were exposed to balanced treatment,but not if they were exposed to male-biased treatment.Females from the male-biased treatment showed interindividual differences in plasticity and no repeatability in flight performance.Offspring showed balanced sex-ratio and similar survivorship,development,and feeding latency independently of the parental treatment;however,females exposed to male-biased treatment produced offspring with higher differences in exploration plasticity and daughters less explorative and with higher unpredictable thigmotaxis.We propose prolonged copulation as courtship at balanced sex-ratio but a cost to females under male-biased sex-ratio.Cross-generational effects in behavioral variability may be a mechanism to cope with predicted future environments.
基金The Provincial Administration of Arezzo and the Italian Ministry of Education,University and Research(PRIN 2010-2011,20108 TZKHC)financially and logistically supported the research.M.A.was financed by the Fondo di Ateneo per la Ricerca 2020'of the University of Sassari.
文摘One of the factors facilitating the expansion and proliferation of wild boar Sus scrofa is the plasticity of its reproductive biology.Nevertheless,the real influence of maternal and environmental factors on number and sex of the offspring is stll controversial.While the litter size was shown to be related with the maternal condition,the strength of this relation remains to be understood,together with the possible role played by environmental conditions.Analogously,it is unclear whether wild boar females can adjust their offspring sex.We investigated multiple aspects of wild boar maternal investment by means of a 10-year dataset of female reproductive traits and a set of biologically meaningful environmental variables.The maternal condition slightly affected the litter size but not the offspring sex,and environment did not affect the litter size or the offspring sex.Moreover,mothers did not cope with the higher costs entailed by producing sons by placing them in the most advantageous intrauterine position,nor by allocating less resources on daughters.Our set of results showed that the female reproductive investment is quite rigid in comparison with other aspects of wild boar reproductive biology.Wild boar females seem to adopt a typical rstrategy,producing constantly large litters and allocating resources on both sexes regardless of internal and external conditions.Such strategy may be adaptive to cope with environmental unpredictability and an intense human harvest,contributing to explain the extreme success of wild boar within human-dominated landscapes.
基金Natural Science Foundation of China(30900162,3096006 and 31370402)Fundamental Research Funds for the Central Universities(lzujbky-2013-102).
文摘Aims sex allocation in plants is often plastic,enabling individuals to adjust to variable environments.However,the predicted male-biased sex allocation in response to low resource conditions has rarely been experimentally tested in hermaphroditic plants.in particular,it is unknown whether distal flowers in linear inflorescences show a larger shift to male allocation relative to basal flowers when resources are reduced.in this study,we measure position-depend-ent plasticity of floral sex allocation within racemes of Aconitum gymnandrum in response to reduced resource availability.Methods using a defoliation treatment in the field applied to potted plants from a nested half-sibling design,we examined the effects of the treatment,flower position,family and their interactions.Important Findingsallocation to male function increased with more distal flower posi-tion,while female allocation either did not change with position or declined at the most distal flowers.Defoliation significantly reduced the mass of both the androecium and gynoecium,but not anther number or carpel number.gynoecial mass declined more strongly with defoliation than did androecial mass,resulting in a significant increase in the androecium/gynoecium ratio as predicted by sex allocation theory.Plastic responses of androecium mass and gynoecium mass were affected by flower position,with less mass lost in basal flowers,but similar plastic magnitude in both sexual traits across flower position lead to consistent variation in the androecium/gynoecium ratio along the inflorescence.a sig-nificant treatment*paternal family interaction for the androecium/gynoecium ratio is evidence for additive genetic variation for plastic floral sex allocation,which means that further evolution of alloca-tion can occur.
