Evolution of exclusive paternal care in arthopods

Exclusive male care of offspring is the rarest form of postzygotic parental care among animals and has arisen independently in only 13 arthropod taxa. To distinguish the effects of sexual selection from those of natural selec tion on the evolution of arthropod paternal care, predictions concerning se veral life-history and behavioral traits resulting from both forms of selec tion are made and tested across all known tars with exclusive paternal care . Comparisons suggest parallels between prezygotic nuptial gifts and exclus ive postzygotic male care and support the hypothesis that, in arthropods, m ale behaviors that enhance female reproductive success either directly, by releasing females from the fecundity constraints of maternal care (enhanced fecundity hypothesis), or indirectly, by identifying mates with superior g enes (handicap principle), are traits on which sexual selection has acted. Under such conditions, males that are willing to guard young become preferr ed mates for gravid females and enjoy greater promiscuity than males that a re unable or unwilling to guard. Females use nest construction or the act o f guarding another female's eggs as honest signals of paternal intent and q uality.