6533b826fe1ef96bd1283bc8

RESEARCH PRODUCT

Density dependence of infanticide and recognition of pup sex in male bank voles

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[Infanticide — the killing of conspecific young — is a common phenomenon in many invertebrate and vertebrate species, particularly common in rodents. It can increase juvenile mortality and, thus, affect population growth. Male infanticide is explained by adaptive hypotheses based on sexual selection. Removing future competitors for mating opportunities would require recognition of pup sex and directing infanticide against male pups. We studied whether the sex of a pup and population density affect male bank voles' ( Myodes glareolus ) aggressive behaviour towards conspecific pups. Population density increased aggressiveness. Against our predictions, male bank voles from high density populations reacted more aggressively towards female than male pups. No sex bias in aggressive behaviour was found among males from low density populations. Our study is the first one to show that males are able to recognize pup sex and act accordingly. We suggest resource competition as an explanation for male infanticide. Our results suggest that females are the critical sex in species where female territoriality and saturation of reproductive space determine the social structure and individual reproductive success. Thus, selective infanticide of female pups in high density populations may act to reduce future female–female competition and enhance the perpetrator male's inclusive fitness., Infanticide — the killing of conspecific young — is a common phenomenon in many invertebrate and vertebrate species, particularly common in rodents. It can increase juvenile mortality and, thus, affect population growth. Male infanticide is explained by adaptive hypotheses based on sexual selection. Removing future competitors for mating opportunities would require recognition of pup sex and directing infanticide against male pups. We studied whether the sex of a pup and population density affect male bank voles' ( Myodes glareolus ) aggressive behaviour towards conspecific pups. Population density increased aggressiveness. Against our predictions, male bank voles from high density populations reacted more aggressively towards female than male pups. No sex bias in aggressive behaviour was found among males from low density populations. Our study is the first one to show that males are able to recognize pup sex and act accordingly. We suggest resource competition as an explanation for male infanticide. Our results suggest that females are the critical sex in species where female territoriality and saturation of reproductive space determine the social structure and individual reproductive success. Thus, selective infanticide of female pups in high density populations may act to reduce future female–female competition and enhance the perpetrator male's inclusive fitness.]