Acoustics Associated with Paternal Care and Territorial Behaviors in a Glassfrog with Prolonged Egg-Attendance

Abstract

Vocalizations can vary in relation to individuals and species, and their function is highly dependent on social context. Parental care can influence calling behavior because of the energetic constraints imposed by performing both tasks simultaneously. However, little is known about the association of acoustic traits with parental care across species that continue to call and accumulate multiple clutches while attending their offspring. In this study, we quantified variation in temporal and spectral call traits in relation to paternal care under natural field conditions in a glassfrog species (Centrolenidae) from the Costa Rican Atlantic rainforest. Specifically, we explored if the calls of males observed in egg-attendance activities differ from those of single individuals not displaying parental care in their call rate, call duration, and dominant frequency. In a second series of analyses generated by additional field observations, we assessed variation in the same acoustic traits in relation to call type by comparing the call of single non-attending males (advertisement call) with that of individuals participating in male−male, long-range acoustic disputes (aggressive call). Our results demonstrate that adult males engaged in egg-attendance or territorial encounters have a different call rate but not dominant frequency or call duration relative to individuals not engaged in these activities. Our findings show that non-attending individuals call more often than attending individuals, but that individuals involved in male−male interactions exhibited the highest call rates overall. Based on these results, we discuss the hypothetical role of call rate as an indicator of male condition with respect to both male−male and male−female interactions. The findings of this study are expected to be helpful for future taxonomic assessments of Hyalinobatrachium talamancae and increase our understanding on the evolution of bioacoustics and natural history aspects associated with paternal care and territoriality in neotropical frogs.