Aggressive interactions and intermale spacing in choruses of the leaf-folding frog,Afrixalus delicatus

Abstract

Intermale spacing was examined in caged Afrixalus delicatus choruses. Males maintained an individual distance using an advertisement call, an encounter call and physical combat (or the threat of combat). An increase from low to intermediate chorus size (2-4 males) led to a decrease in nearest calling neighbour distances. At high chorus sizes (5-8 males) males maintained a minimum individual distance of 30-35 cm. New calling males were not accommodated in the chorus once eight males were calling. As the chorus size increased, a greater number of aggressive interactions were required to maintain the minimum distance. The spatial separation of calling males reduces the number of competitors when space is limited. The maintenance of a preferred minimum individual distance may increase a male’s reproductive success by reducing acoustic interference with neighbouring males as well as providing a clear pathway for female approach.