Title

Territory acquisition and maintenance in a neotropical frog, Eleutherodactylus coqui

Date of Completion

January 2002

Keywords

Biology, Ecology|Biology, Zoology

Degree

Ph.D.

Abstract

Eleutherodactylus coqui (Leptodactylidae) is a highly site specific species of frog, and males inhabit multi-purpose territories for several weeks to several years. Home ranges include retreat sites in sheltered areas (e.g., fallen leaves) and elevated calling sites for males. Male E. coqui use the retreat sites as oviposition sites in which they brood their clutches of eggs. The objective of this study was to examine the factors that affect the acquisition and maintenance of territories by male E. coqui. I removed resident males from territories to observe how individuals established territories. The territorial system of E. coqui is characterized by the fluid borders between established residents and the frequent turnover of resident males. Most new residents moved throughout the forest in search of opportunities to enter the chorus (i.e., floaters), while other new residents were previously non-territorial individuals from the area (i.e., sit-and-waiters). ^ During territory maintenance, male E. coqui demonstrates a moderate repeatability of calling rates and a low variation in early evening calling rates. This may mean that a female preference for high calling rates has little effect on male mating success. The interrupted chorusing pattern of individual callers in this species may be due to the limitations on the amount of energy that can be stored to fuel call production. Because a defendable retreat site is needed for prolonged parental care, males may best maximize their reproductive success by obtaining territories and calling from them on most nights, occasionally at high rates. ^ The territories of many neighboring residents overlap as the individuals share areas used for calling over the course of time. The short-term cost of allowing another individual to call within the home range probably is minimal if the resident is feeding to replenish lost energy reserves or brooding a clutch. E. coqui produces aggressive calls that vary in length. Males do not vary the length or number of the calls produced in response to variable length stimuli during calling site defense. Males therefore, can easily alter the behavior of nearby callers by producing a few, short aggressive to maintain inter-male distances. ^