The mating system of three territorial butterflies in Costa Rica

Abstract

Territorial behavior was observed in three Costa Rican butterfly species whose males perch in sunspots and open areas along a forest stream. Males of Calaenorrhinus approximatus occupied sunspot clearings for 1-2 hr in the early morning, with the same individual defending a site for up to 19 days. Males of Astraptes galesus cassius perched on the broad leaves of a piper in a tree fall clearing by the stream, with one individual returning for 17 days as the territory holder. Males of Mesosemia asa asa perched in streamside vegetation with a maximum territorial tenure of 25 days. Territorial males of all three species regularly patrolled the area about their perching sites and responded to intruders with circling chases and ascending pursuit flights. One mating occurred in the territory of a C. approximatus male, and three were recorded for M. asa in or near a perch territory. The mating systems of these species appear convergent with other butterflies whose males defend landmark territories.