In butterflies, male reproductive success is highly related to the quality and the size of the spermatophore transferred to the female. The spermatophore is a capsule produced by the male during copulation, which in m...In butterflies, male reproductive success is highly related to the quality and the size of the spermatophore transferred to the female. The spermatophore is a capsule produced by the male during copulation, which in many species contains sperm in addition to a nuptial gift, and which is digested by the female after copulation. The nuptial gift may contribute to egg production and offspring quality, and in some cases also to female body maintenance. The production of the spermatophore, however, represents a cost for the male and, in polyandrous species, ejaculates are sometimes allocated adaptively across matings. Nonetheless, although the ecological factors affecting the reproductive success of female butterflies have been the topic of numerous studies, little information exists on the factors affecting males＇ contribution to reproduction, and the indirect impacts on female fecundity and fitness. We used the Glanville fritillary butterfly, Melitaea cinxia （Linnaeus, 1758） （Nymphalidae）, in order to assess variation in male allocation to matings. In this species, smaller males produce smaller spermatophores, but variation in spermatophore size is not correlated with female reproductive success. We show that spermatophore size increases with male age at first mating, decreases with mating frequency and adult food-deprivation, and is not influenced by developmental food-limitation. The length of copulation period does not influence the spermatophore size nor influences the polyandrous mating behavior in this species. Male contribution to his spermatophore size is clearly influenced by his condition and adult-resource at the time of mating. Despite this variation, spermatophore size does not seem to have a direct impact on female reproductive output or mating behavior.展开更多
Aims Understanding fluctuations in plant reproductive investment can constitute a key challenge in ecology,conservation and manage-ment.Masting events of trees(i.e.the intermittent and synchronous production of abunda...Aims Understanding fluctuations in plant reproductive investment can constitute a key challenge in ecology,conservation and manage-ment.Masting events of trees(i.e.the intermittent and synchronous production of abundant seeding material)is an extreme example of such fluctuations.Our objective was to establish the degree of spa-tial and temporal synchrony in common four masting tree species in boreal Finland and account for potential causal drivers of these patterns.Methods We investigated the spatial intraspecific and temporal interspe-cific fluctuations in annual seed production of four tree species in Finland,silver birch Betula pendula Roth,downy birch Betula pubescens Ehrh.,Norway spruce Picea abies(L.)H.Karst.and row-anberry Sorbus aucuparia L.We also tested to see whether varia-tions in seed production were linked to annual weather conditions.Seeding abundance data were derived from tens of stands per spe-cies across large spatial scales within Finland during 1979 to 2014(for rowanberries only 1986 to 2014).Important Findings All species showed spatial synchrony in seed production at scales up to 1000 km.Annual estimates of seed production were strongly correlated between species.Spring and summer temperatures explained most variation in crop sizes of tree species with 0-to 2-year time lags,whereas rainfall had relatively little influence.Warm weather during flowering(May temperature)in the flower-ing year(Year t)and 2 years before(t−2)were correlated with seed production.However,high May temperatures during the previous year(t−1)adversely affected seed production.Summer tempera-tures in Year t−1 was positively correlated with seed production,likely because this parameter enhances the development of flower primordials,but the effect was negative with a time lag of 2 years.The negative feedback in temperature coefficients is also likely due to patterns of resource allocation,as abundant flowering and seed production in these species is thought to reduce the sub-sequent initiation of potential new flower buds.Since the most important weather variables also showed spatial correlation up to 1000 km,weather parameters likely explain much of the spatial and temporal synchrony in seed production of these four studied tree species.展开更多
文摘In butterflies, male reproductive success is highly related to the quality and the size of the spermatophore transferred to the female. The spermatophore is a capsule produced by the male during copulation, which in many species contains sperm in addition to a nuptial gift, and which is digested by the female after copulation. The nuptial gift may contribute to egg production and offspring quality, and in some cases also to female body maintenance. The production of the spermatophore, however, represents a cost for the male and, in polyandrous species, ejaculates are sometimes allocated adaptively across matings. Nonetheless, although the ecological factors affecting the reproductive success of female butterflies have been the topic of numerous studies, little information exists on the factors affecting males＇ contribution to reproduction, and the indirect impacts on female fecundity and fitness. We used the Glanville fritillary butterfly, Melitaea cinxia （Linnaeus, 1758） （Nymphalidae）, in order to assess variation in male allocation to matings. In this species, smaller males produce smaller spermatophores, but variation in spermatophore size is not correlated with female reproductive success. We show that spermatophore size increases with male age at first mating, decreases with mating frequency and adult food-deprivation, and is not influenced by developmental food-limitation. The length of copulation period does not influence the spermatophore size nor influences the polyandrous mating behavior in this species. Male contribution to his spermatophore size is clearly influenced by his condition and adult-resource at the time of mating. Despite this variation, spermatophore size does not seem to have a direct impact on female reproductive output or mating behavior.
基金A.L.received financial support from the Academy of Finland(grant no.275606).
文摘Aims Understanding fluctuations in plant reproductive investment can constitute a key challenge in ecology,conservation and manage-ment.Masting events of trees(i.e.the intermittent and synchronous production of abundant seeding material)is an extreme example of such fluctuations.Our objective was to establish the degree of spa-tial and temporal synchrony in common four masting tree species in boreal Finland and account for potential causal drivers of these patterns.Methods We investigated the spatial intraspecific and temporal interspe-cific fluctuations in annual seed production of four tree species in Finland,silver birch Betula pendula Roth,downy birch Betula pubescens Ehrh.,Norway spruce Picea abies(L.)H.Karst.and row-anberry Sorbus aucuparia L.We also tested to see whether varia-tions in seed production were linked to annual weather conditions.Seeding abundance data were derived from tens of stands per spe-cies across large spatial scales within Finland during 1979 to 2014(for rowanberries only 1986 to 2014).Important Findings All species showed spatial synchrony in seed production at scales up to 1000 km.Annual estimates of seed production were strongly correlated between species.Spring and summer temperatures explained most variation in crop sizes of tree species with 0-to 2-year time lags,whereas rainfall had relatively little influence.Warm weather during flowering(May temperature)in the flower-ing year(Year t)and 2 years before(t−2)were correlated with seed production.However,high May temperatures during the previous year(t−1)adversely affected seed production.Summer tempera-tures in Year t−1 was positively correlated with seed production,likely because this parameter enhances the development of flower primordials,but the effect was negative with a time lag of 2 years.The negative feedback in temperature coefficients is also likely due to patterns of resource allocation,as abundant flowering and seed production in these species is thought to reduce the sub-sequent initiation of potential new flower buds.Since the most important weather variables also showed spatial correlation up to 1000 km,weather parameters likely explain much of the spatial and temporal synchrony in seed production of these four studied tree species.
