We studied spatial variation in the effects of environment and network size on species positions and roles in multiple flea–mammal networks from four biogeographic realms.We asked whether species positions(measured a...We studied spatial variation in the effects of environment and network size on species positions and roles in multiple flea–mammal networks from four biogeographic realms.We asked whether species positions(measured as species strength[SS],the degree of interaction specialization[d],and the eigenvector centrality[C])or the roles of fleas and their hosts in the interaction networks:(a)are repeatable/conserved within a flea or a host species;(b)vary in dependence on environmental variables and/or network size;and(c)the effects of environment and network size on species positions or roles in the networks depend on species traits.The repeatability analysis of species position indices for 441 flea and 429 host species,occurring in at least two networks,demonstrated that the repeatability of SS,d,and C within a species was significant,although not especially high,suggesting that the indices’values were affected by local factors.The majority of flea and host species in the majority of networks demonstrated a peripheral role.A value of at least one index of species position was significantly affected by environmental variables or network size in 41 and 36,respectively,of the 52 flea and 52 host species that occurred in multiple networks.In both fleas and hosts,the occurrence of the significant effect of environment or network size on at least one index of species position,but not on a species’role in a network,was associated with some species traits.展开更多
We tested for the effects of latitude and geographic range size(GRS)on body size,leg length,and sexual size dimorphism(SSD)across 103 species offleas,taking into account phylogenetic between-species relationships.When ...We tested for the effects of latitude and geographic range size(GRS)on body size,leg length,and sexual size dimorphism(SSD)across 103 species offleas,taking into account phylogenetic between-species relationships.When the data on body size were combined for males and females,the positive correlation between body size and latitude,but not GRS,was revealed.When the analysis was restricted to one sex only,the effect of latitude appeared to be non-significant for females,whereas male body size increased with an increase in latitude.Intraspecific body size variation was not associated with either the latitude or the latitudinal span of the geographic range,independently of which data subset was analyzed.No evidence of association between size-independent tibia length and latitude was found for either females,males,or both sexes combined.The degree of SSD decreased with a decrease in latitude but was not affected by GRS.We conclude that macroecological patterns might be manifested differently in males and females.This should be kept in mind while searching for these patterns.展开更多
We investigated the performance trade-offs of fleas(Siphonaptera)while adapting to a novel host using two host generalists(Xenopsylla conformis and Xenopsylla ramesis)and one host specialist(Parapulex chephrenis)maint...We investigated the performance trade-offs of fleas(Siphonaptera)while adapting to a novel host using two host generalists(Xenopsylla conformis and Xenopsylla ramesis)and one host specialist(Parapulex chephrenis)maintained on their principal hosts(Meriones crassus for Xenopsylla and Acomys cahirinus for P.chephrenis).We asked whether,over generations,(i)a host generalist may become a specialist by evolving the ability to exploit a novel host and losing the ability to exploit an original host and(ii)a host specialist can become a generalist by evolving the ability to exploit a novel host without losing the ability to exploit an original host.We established an experimental line of each species on a novel host(Acomys russatus for Xenopsylla and M.crassus for P.chephrenis)and maintained this line on this host during 23 generations.We compared reproductive performance of progenitors of each line and their descendants when they exploited either original or novel host in terms of egg number and size,hatching success,offspring production,and offspring size.We found changes in performance over generations in female offspring size only.Xenopsylla conformis demonstrated a tendency to become a host specialist(increased performance on the novel host with a concomitant decreased performance on the original host),whereas P.chephrenis demonstrated a tendency to become a host generalist(increased performance on the novel host without a concomitant decreased performance on the original host).We conclude that the probability of generalist to specialist transition,and vice versa,is context-dependent and varies between species.展开更多
基金supported by Israel Science Foundation(grant 548/23 to BRK and ISK).
文摘We studied spatial variation in the effects of environment and network size on species positions and roles in multiple flea–mammal networks from four biogeographic realms.We asked whether species positions(measured as species strength[SS],the degree of interaction specialization[d],and the eigenvector centrality[C])or the roles of fleas and their hosts in the interaction networks:(a)are repeatable/conserved within a flea or a host species;(b)vary in dependence on environmental variables and/or network size;and(c)the effects of environment and network size on species positions or roles in the networks depend on species traits.The repeatability analysis of species position indices for 441 flea and 429 host species,occurring in at least two networks,demonstrated that the repeatability of SS,d,and C within a species was significant,although not especially high,suggesting that the indices’values were affected by local factors.The majority of flea and host species in the majority of networks demonstrated a peripheral role.A value of at least one index of species position was significantly affected by environmental variables or network size in 41 and 36,respectively,of the 52 flea and 52 host species that occurred in multiple networks.In both fleas and hosts,the occurrence of the significant effect of environment or network size on at least one index of species position,but not on a species’role in a network,was associated with some species traits.
文摘We tested for the effects of latitude and geographic range size(GRS)on body size,leg length,and sexual size dimorphism(SSD)across 103 species offleas,taking into account phylogenetic between-species relationships.When the data on body size were combined for males and females,the positive correlation between body size and latitude,but not GRS,was revealed.When the analysis was restricted to one sex only,the effect of latitude appeared to be non-significant for females,whereas male body size increased with an increase in latitude.Intraspecific body size variation was not associated with either the latitude or the latitudinal span of the geographic range,independently of which data subset was analyzed.No evidence of association between size-independent tibia length and latitude was found for either females,males,or both sexes combined.The degree of SSD decreased with a decrease in latitude but was not affected by GRS.We conclude that macroecological patterns might be manifested differently in males and females.This should be kept in mind while searching for these patterns.
基金supported by Israel Science Foundation(grant 149/17 to ISK and BRK).
文摘We investigated the performance trade-offs of fleas(Siphonaptera)while adapting to a novel host using two host generalists(Xenopsylla conformis and Xenopsylla ramesis)and one host specialist(Parapulex chephrenis)maintained on their principal hosts(Meriones crassus for Xenopsylla and Acomys cahirinus for P.chephrenis).We asked whether,over generations,(i)a host generalist may become a specialist by evolving the ability to exploit a novel host and losing the ability to exploit an original host and(ii)a host specialist can become a generalist by evolving the ability to exploit a novel host without losing the ability to exploit an original host.We established an experimental line of each species on a novel host(Acomys russatus for Xenopsylla and M.crassus for P.chephrenis)and maintained this line on this host during 23 generations.We compared reproductive performance of progenitors of each line and their descendants when they exploited either original or novel host in terms of egg number and size,hatching success,offspring production,and offspring size.We found changes in performance over generations in female offspring size only.Xenopsylla conformis demonstrated a tendency to become a host specialist(increased performance on the novel host with a concomitant decreased performance on the original host),whereas P.chephrenis demonstrated a tendency to become a host generalist(increased performance on the novel host without a concomitant decreased performance on the original host).We conclude that the probability of generalist to specialist transition,and vice versa,is context-dependent and varies between species.
