The reproductive biology of Hypsiboas punctatus (Anura: Hylidae): male territoriality and the possible role of different signals during female choice

Abstract

Anuran amphibians are known to employ acoustic signals as the principal form to access potential mates, while recent studies have highlighted the importance of multiple cues during courtship. Hypsiboas punctatus is a hylid species in which males emit advertisement calls and have sexually dimorphic skin glands (SDSGs). However, knowledge on the reproductive biology of this species is very limited. We present the first systematic field-observational study on the behaviour of H. punctatus, which was complemented by observations under laboratory-controlled conditions. Males exhibit a territorial behaviour as is evidenced by site fidelity, aggressiveness against male intruders (usually involving fights), and signalling behaviour. We found that female choice would be operating at two different levels, which we defined as Initial Exploration (I.E.) and Proximate Exploration (P.E.). These levels would be guided by acoustic signals in I.E., while tactile and/or chemical signals (considering the presence of SDSGs) would be more important in P.E. We also provide descriptions of vocal interaction between males, amplexus, and egg clutch. We suggest that SDSGs located at the mental gland may be important in delivering sexual pheromones to the female during amplexus. Finally, our results are compared to similar behaviours that have been described for related species, and discussed in terms of the probable existence of multimodal communication.