Acoustic Analysis of Novel Female Calls in Japanese Pond Frogs, Pelophylax nigromaculatus and Pelophylax porosus brevipodus

Abstract

In most frogs, males emit calls in the reproductive seasons, whereas females usually do not emit calls. Females of only several frog species have been known to vocalize. I here report female vocalization in two ranid species, Pelophylax nigromaculatus and P. porosus brevipodus in their overlapping reproductive season. Females of these species called in both intraspecific and interspecific interactions. There were no clear differences in acoustic characteristics of female calls between the two species or between interspecific and intraspecific interactions. Based on the situations in which females called, it is implied that functions of the female calls of P. nigromaculatus and P. p. brevipodus are quite different from those of female calls in frogs hitherto reported.