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Plasticity of floral sex allocation within inflorescences of hermaphrodite Aconitum gymnandrum

Journal of Plant Ecology 2015年第2期8卷 130-135页

作者： Zhi-Gang Zhao Zuo-Jun Liu Jeffrey K.Conner State Key Laboratory of Grassland and Agro-Ecosystems School of Life SciencesLanzhou University222 Tianshui Road Chengguan DistrictLanzhou 730000China College of Life Science and Engineering Lanzhou University of Technology287 Langongpin Road Qilihe DistrictLanzhou 730000China Kellogg Biological Station and Department of Plant Biology Michigan State University3700 East Gull Lake DriveHickory CornersMI 49060USA

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.

关键词： Aconitum gymnandrum sex allocation plasticity inflorescence architecture

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Multiple aspects of the maternal reproductive investmentin a polytocous species:What do mothers really control?

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Current Zoology 2023年第2期69卷 136-142页

作者： Rudy Brogi Roberta Chirichella Enrico Merli Marco Apollonio Department of Veterinary Medicine University of Sassarivia Vienna 2I-07100 SassariItaly Department of Humanities and Social Sciences University of Sassarivia Roma 151I-07100 SassariItaly

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.

关键词： investment life history litter size reproduction sex allocation wild boar

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Direct and cross-generational effects of reproduction on fitness and behavioral variability in male-biased environments

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Current Zoology 2023年第3期69卷 339-353页

作者： Iago Sanmartin-Villar Xin Yu Adolfo Cordero-Rivera Universidade de Vigo ECOEVO LabEscola de Enxenaria ForestalCampus Universitario A Xunqueira36005 PontevedraGalizaSpain College of Life Sciences Chongqing Normal UniversityDaxuecheng Middle RdShapingba DistrictChongqing 401333China

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.

关键词： activity environmental perception Ischnura graellsii male harassment sex allocation

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sex ratio variation and sex determination in the mallee dragon Ctenophorus fordi

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Integrative Zoology 2008年第3期3卷 157-165页

作者： Tobias ULLER Gaetano ODIERNA Mats OLSSON School of Biological Sciences University of WollongongWollongongNew South WalesAustralia Department of Structural and Functional Biology University of Naples Federico IINaplesItaly

Recent evidence suggests that many Australian agamids show temperature-dependent sex determination(TSD)with variation in sex determining mechanisms among closely related taxa.However,as shown in other vertebrates,sex ratios can also be influenced by genetic or phenotypic differences among females in their propensity to produce sons or daughters,and these influences might confound any thermal effects of incubation per se.To address these issues,we investigated the determinants of sex ratios in the mallee dragon Ctenophorus fordi,together with a detailed analysis of karyotypes.There was no detectable variation in sex ratios arising from variation among females,clutches or incubation temperatures,which might indicate genetic sex determination for this species.However,there was no evidence of cytologically distinct sex chromosomes using standard banding techniques.The sex ratio pattern in C.fordi strongly contrasts with the results for the congener Ctenophorus pictus,where sex ratios show variation among females.Thus,Australian agamids offer promising opportunities to address fundamental issues in sex ratio biology.

关键词： genetic-dependent sex determination lizard sex ratio sex allocation temperature-dependent sex determination.

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