Meeting Abstract

21.4  Monday, Jan. 4  Role of song in the altitudinal replacement of Neotropical singing mice (Scotinomys) PASCH, Bret; University of Florida bpasch@ufl.edu

Understanding the role of biotic and abiotic factors in limiting species distributions is a fundamental goal in biology. On the highest mountains of Costa Rica and Panamá, the Chiriqui singing mouse (Scotinomys xerampelinus) abruptly replaces Alston’s singing mouse (S. teguina). Singing mice are diurnal insectivorous rodents that inhabit montane cloud forests of Central America, and males commonly emit stereotyped songs that appear to function in male-male aggression. Comparative biogeographical surveys, reciprocal removal experiments, and interspecific behavioral trials demonstrate that S. teguina is limited by the presence of dominant heterospecifics, whereas S. xerampelinus is limited by abiotic factors. Here, I ask how song mediates intra- and interspecific interactions among males by broadcasting conspecific, heterospecific, and control stimuli to both species in the field and laboratory. S. teguina responded to conspecifics but not heterospecifics, whereas S. xerampelinus responded to both. Such behavioral responses to song match interspecific dominance interactions and appear to reinforce altitudinal distributions of singing mice.