Differential responses of large and small male red‐spotted newts,Notophthalmus viridescens, to conspecific chemical cues

Abstract

Male red‐spotted newts, Notophthalmus viridescens, use chemical cues to locate and select potential mates. To investigate whether large and small males respond differentially to chemical cues from conspecifics, we conducted a series of two‐choice Y‐maze tests with odorant stimuli from two large females (LF/LF), one large versus one small female (LF/SF), and one large female placed with four males versus one small female (LF+4M/SF). We found that males responded more rapidly in a LF/LF choice situation than in those involving LF/SF or LF+4M/SF. In addition, small males chose more quickly than did large males. These results suggest that both body size and odorant context affect the speed of odorant responses. By responding differentially to conspecific chemical cues, small males may arrive earlier at a courting area, increasing their chances of successfully guarding and mating with a female.