Theory suggests that males that are larger than their competitors may have increased mating success, due to both greater competitive ability and increased attractiveness to females. We examined how male mating suceess...Theory suggests that males that are larger than their competitors may have increased mating success, due to both greater competitive ability and increased attractiveness to females. We examined how male mating suceess varies with male size in the tessellated darter Etheostoma olmstedi. Previous work has shown that large males tend to move around and breed in vacant breeding sites, and consequently provide less care for their eggs, while smaller individuals can be allopaternal, caring for the eggs of other males as well as for their own. We studied female egg deposition in a natural breeding population using artificial breeding sites and in the laboratory, where female choice of spawning site was restricted to two breeding sites tended by two males of different sizes. In both the field and the laboratory, nests tended by larger males were more likely to receive new eggs. Additionally, the mean size of males associated with a nest was positively correlated with both the maximum coverage of eggs at the nest and the number of times new eggs were deposited. We discuss how the increased mating success of larger males, despite their decreased parental care, may help explain aUopaternal care in this species [Current Zoology 56 （1）： 1-5, 2010].展开更多
In sexually dimorphic species characterized by exaggerated male ornamentation,behavioral isola-tion is often attributed to female preferences for conspecific male signals.Yet,in a number of sexu-ally dimorphic species...In sexually dimorphic species characterized by exaggerated male ornamentation,behavioral isola-tion is often attributed to female preferences for conspecific male signals.Yet,in a number of sexu-ally dimorphic species,male mate choice also results in behavioral isolation.In many of these cases,the female traits that mediate species boundaries are unclear.Females in sexually dimorphic species typically lack many of the elaborate traits that are present in males and that are often used for taxonomic classification of species.In a diverse and largely sexually dimorphic group of fishes called darters(Percidae:Etheostoma),male mate choice contributes to behavioral isolation be-tween a number of species;however,studies addressing which female traits males prefer are lack-ing.In this study,we identified the dominant female pattern for two sympatric species,Etheostoma zonale and Etheostoma barrenense,using pattern energy analysis,and we used discriminate func-tion analysis to identify which aspects of female patterning can reliably classify species.We then tested the role of female features in male mate choice for E.zonale,by measuring male preference for computer animations displaying the identified(species specific)conspecific features.We found that the region above the lateral line is important in mediating male mate preferences,with males spending a significantly greater proportion of time with animations exhibiting conspecific female patterning in this region than with animations exhibiting heterospecific female patterning.Our results suggest that the aspects of female phenotypes that are the target of male mate choice are different from the conspicuous male phenotypes that traditionally characterize species.展开更多
基金funded by a grant from the National Science Foundation (IOB-0450807) to S.H.A.by a Natural Sciences and Engineering Research Council (NSERC) of Canada Postdoctoral Fellowship to K.A.S.by Yale University
文摘Theory suggests that males that are larger than their competitors may have increased mating success, due to both greater competitive ability and increased attractiveness to females. We examined how male mating suceess varies with male size in the tessellated darter Etheostoma olmstedi. Previous work has shown that large males tend to move around and breed in vacant breeding sites, and consequently provide less care for their eggs, while smaller individuals can be allopaternal, caring for the eggs of other males as well as for their own. We studied female egg deposition in a natural breeding population using artificial breeding sites and in the laboratory, where female choice of spawning site was restricted to two breeding sites tended by two males of different sizes. In both the field and the laboratory, nests tended by larger males were more likely to receive new eggs. Additionally, the mean size of males associated with a nest was positively correlated with both the maximum coverage of eggs at the nest and the number of times new eggs were deposited. We discuss how the increased mating success of larger males, despite their decreased parental care, may help explain aUopaternal care in this species [Current Zoology 56 （1）： 1-5, 2010].
基金This research was funded in part by an Animal Behavior Society Student Research Grant provided to NSR.
文摘In sexually dimorphic species characterized by exaggerated male ornamentation,behavioral isola-tion is often attributed to female preferences for conspecific male signals.Yet,in a number of sexu-ally dimorphic species,male mate choice also results in behavioral isolation.In many of these cases,the female traits that mediate species boundaries are unclear.Females in sexually dimorphic species typically lack many of the elaborate traits that are present in males and that are often used for taxonomic classification of species.In a diverse and largely sexually dimorphic group of fishes called darters(Percidae:Etheostoma),male mate choice contributes to behavioral isolation be-tween a number of species;however,studies addressing which female traits males prefer are lack-ing.In this study,we identified the dominant female pattern for two sympatric species,Etheostoma zonale and Etheostoma barrenense,using pattern energy analysis,and we used discriminate func-tion analysis to identify which aspects of female patterning can reliably classify species.We then tested the role of female features in male mate choice for E.zonale,by measuring male preference for computer animations displaying the identified(species specific)conspecific features.We found that the region above the lateral line is important in mediating male mate preferences,with males spending a significantly greater proportion of time with animations exhibiting conspecific female patterning in this region than with animations exhibiting heterospecific female patterning.Our results suggest that the aspects of female phenotypes that are the target of male mate choice are different from the conspicuous male phenotypes that traditionally characterize species.
