Communal oviposition and lack of parental care in Batrachoseps nigriventris (Caudata: Plethodontidae) with a discussion of the evolution of breeding behavior in plethodontid salamanders

Although plethodontid salamanders are characterized by a diversity of life histories, several aspects of their breeding biology are highly conserved. Two of these are solitary oviposition and attendance of clutches by females until hatching. We infer evolutionary changes in these reproductive features based on the discovery of oviposition sites and eggs of two species, Batrachoseps nigriventris and B. wrighti. Batrachoseps nign'uenkis deviates from the ancestral reproductive pattern in two ways: most clutches are laid at communal oviposition sites and female care has been lost. In contrast, B. wrighti may deviate from the ancestral pattern only in the loss of maternal care. A review of the reproductive biology of Batrachoseps and other plethodontids reveals that female attendance of eggs was lost in the ancestor of all Batrachoseps, whereas communal oviposition likely originated following the basal split within the genus. Additionally, communal oviposition and abandonment of clutches have evolved in two other plethodontid clades: Nototriton/Oedipina and Hemidactylium. Studies of taxa that have lost parental care may give insight into factors favoring the maintenance of parental care in other lineages.