Call site selection in a hybrid population of treefrogs

Abstract

Call site selection in the treefrogs Hyla cinerea and Hyla gratiosa has been regarded as an important behavioural mechanism in maintaining reproductive isolation. Its probable genetic basis was evaluated in a hybrid population near Auburn, Alabama. Allozymically-defined parental and hybrid classes exhibited distinct call site preferences. The pure parental categories demonstrated expected site differences: 41 H. gratiosa called from the ponds proper, whereas 92 H. cinerea called out of the water. Eighteen out of 19 F 1 hybrids selected intermediate call sites along the shoreline. Preferred call sites of backcross individuals were generally comparable to those of their respective parental species. Observed site specificities in these various genetic classes demonstrate a heritable component in site-selection behaviour.