Seminal gifts range from important material donations to items that provide little direct benefit to females.Promiscuous,female silk corn flies Euxesta eluta expel and consume male ejaculates immediately after mating....Seminal gifts range from important material donations to items that provide little direct benefit to females.Promiscuous,female silk corn flies Euxesta eluta expel and consume male ejaculates immediately after mating.The evolution and function of this peculiar behavior are currently unknown.We performed a series of experiments aimed to:determine if females under different dietary regimes derive nutrients or water for survival and/or reproduction from ejaculate consumption,if males suffer a fitness cost from supplying females with ejaculates,and if females prefer to mate and/or are more likely to store sperm from well fed than nutritionally stressed presumably inferior males.Experiments revealed that protein deprived E.eluta females derive nutrients for ovarian development through consumption of ejaculates of protein fed males.No seminal products affecting survival appear to be transferred in the consumed ejaculate.However,ovarian development,in contrast to testes growth,occurs in detriment of longevity.Females preferred to mate with protein fed males,yet sperm retention in spermathecae was extremely rare after a single mating.This finding suggests that females could be exerting post copulatory control.A key question that remained to be addressed for the understanding of this puzzling and promiscuous mating system is what ecological factors or male traits drive females to retain sperm from one or several males in order to achieve and/or maximize fertilization potential.展开更多
Among tephritid fruit flies,hybridization has been found to produce local adaptation and speciation,and in the case of pest species,induce behavioral and ecological alterations that can adversely impact efficient pest...Among tephritid fruit flies,hybridization has been found to produce local adaptation and speciation,and in the case of pest species,induce behavioral and ecological alterations that can adversely impact efficient pest management.Thefraterculus species group within Anastrepha (Diptera:Tephritidae),is a rapidly radiating aggregate,which includes cryptic species complexes,numerous sister species,and several pest species. Molecular studies have highlighted the possibility of introgression between A.fraterculus and A.obliqua.Reproductive isolation has been studied among morphotypes of the A. fraterculus species complex as a tool for species delimitation.Here we examined the exis- tence and strength of prezygotic and postzygotic isolation between sympatric populations of two closely related species within the highly derivedfraterculus group (A.fraterculus and A.obliqua),coexisting in nature.Although adults of both species showed a strong tendency for assortative mating,a small proportion of hybrid pairings in both directions were observed.We also observed asymmetric postzygotic isolation,with one hybrid cross displaying a strong reduction in fecundity and F1 egg fertility.Survival was greater for the progeny of homotypic and hybrid crosses in the maternal host.There was a marked female biased sex ratio distortion for both F1 hybrid adults.Hybridization between A.fraterculus and A.obliqua in nature may be difficult but possible;these two species display stronger reproductive isolation than all pairs of species previously examined in the A.fraterculus species complex.Asymmetric postzygotie isolation is suggestive of Wolbachia mediated cytoplasmic incompatibilities that may be exploited in area-wide pest management.展开更多
Promiscuous mating systems provide the opportunity for females to bias fertilization toward particular males.However,distinguishing between male sperm com-petition and active female sperm choice is difficult for speci...Promiscuous mating systems provide the opportunity for females to bias fertilization toward particular males.However,distinguishing between male sperm com-petition and active female sperm choice is difficult for species with internal fertilization.Nevertheless,species that store and use sperm of different males in different storing struc-tures and species where females are able to expel all or part of the ejaculates after cop-ulation may be able to bias fertilization.We report a series of experiments aimed at pro-viding evidence of female sperm choice in Euxesta eluta(Hendel),a species of ulidiid fly that expels and consumes ejaculates after copulation.We found no evidence of greater reproductive success for females mated singly,multiply with the same male,or mated multiply with different males.Female E.eluta possesses two spherical spermathecae and a bursa copulatrix for sperm storage,with a ventral receptacle.There was no significant difference in storing more sperm in spermathecae 24 h after copulation than immediately after copulation.Females mated with protein-fed males had greater reproductive success than similar females mated to protein-deprived males.Protein-fed females prevented to consume the ejaculate,retained more sperm when mated to protein-fed males than when mated to protein-deprived males.Our results suggest that female E.eluta can exert control of sperm retention of higher quality males through ejaculate ejection.展开更多
基金This experiments where funded with PICT 2015 N°0191 awarded to SA.
文摘Seminal gifts range from important material donations to items that provide little direct benefit to females.Promiscuous,female silk corn flies Euxesta eluta expel and consume male ejaculates immediately after mating.The evolution and function of this peculiar behavior are currently unknown.We performed a series of experiments aimed to:determine if females under different dietary regimes derive nutrients or water for survival and/or reproduction from ejaculate consumption,if males suffer a fitness cost from supplying females with ejaculates,and if females prefer to mate and/or are more likely to store sperm from well fed than nutritionally stressed presumably inferior males.Experiments revealed that protein deprived E.eluta females derive nutrients for ovarian development through consumption of ejaculates of protein fed males.No seminal products affecting survival appear to be transferred in the consumed ejaculate.However,ovarian development,in contrast to testes growth,occurs in detriment of longevity.Females preferred to mate with protein fed males,yet sperm retention in spermathecae was extremely rare after a single mating.This finding suggests that females could be exerting post copulatory control.A key question that remained to be addressed for the understanding of this puzzling and promiscuous mating system is what ecological factors or male traits drive females to retain sperm from one or several males in order to achieve and/or maximize fertilization potential.
文摘Among tephritid fruit flies,hybridization has been found to produce local adaptation and speciation,and in the case of pest species,induce behavioral and ecological alterations that can adversely impact efficient pest management.Thefraterculus species group within Anastrepha (Diptera:Tephritidae),is a rapidly radiating aggregate,which includes cryptic species complexes,numerous sister species,and several pest species. Molecular studies have highlighted the possibility of introgression between A.fraterculus and A.obliqua.Reproductive isolation has been studied among morphotypes of the A. fraterculus species complex as a tool for species delimitation.Here we examined the exis- tence and strength of prezygotic and postzygotic isolation between sympatric populations of two closely related species within the highly derivedfraterculus group (A.fraterculus and A.obliqua),coexisting in nature.Although adults of both species showed a strong tendency for assortative mating,a small proportion of hybrid pairings in both directions were observed.We also observed asymmetric postzygotic isolation,with one hybrid cross displaying a strong reduction in fecundity and F1 egg fertility.Survival was greater for the progeny of homotypic and hybrid crosses in the maternal host.There was a marked female biased sex ratio distortion for both F1 hybrid adults.Hybridization between A.fraterculus and A.obliqua in nature may be difficult but possible;these two species display stronger reproductive isolation than all pairs of species previously examined in the A.fraterculus species complex.Asymmetric postzygotie isolation is suggestive of Wolbachia mediated cytoplasmic incompatibilities that may be exploited in area-wide pest management.
基金supported by the Fund for Scientific and Technological Research(FONCyT PICT 2018-03521).
文摘Promiscuous mating systems provide the opportunity for females to bias fertilization toward particular males.However,distinguishing between male sperm com-petition and active female sperm choice is difficult for species with internal fertilization.Nevertheless,species that store and use sperm of different males in different storing struc-tures and species where females are able to expel all or part of the ejaculates after cop-ulation may be able to bias fertilization.We report a series of experiments aimed at pro-viding evidence of female sperm choice in Euxesta eluta(Hendel),a species of ulidiid fly that expels and consumes ejaculates after copulation.We found no evidence of greater reproductive success for females mated singly,multiply with the same male,or mated multiply with different males.Female E.eluta possesses two spherical spermathecae and a bursa copulatrix for sperm storage,with a ventral receptacle.There was no significant difference in storing more sperm in spermathecae 24 h after copulation than immediately after copulation.Females mated with protein-fed males had greater reproductive success than similar females mated to protein-deprived males.Protein-fed females prevented to consume the ejaculate,retained more sperm when mated to protein-fed males than when mated to protein-deprived males.Our results suggest that female E.eluta can exert control of sperm retention of higher quality males through ejaculate ejection.
