New records and a notable observation of potentially predator-avoiding amplectic behaviour in Boophis erythrodactylus from Madagascar

ABSTRACT

The Red-fingered Bright-eyed Frog Boophis erythrodactylus is an endemic, range-restricted arboreal frog found only in the eastern rainforests of Madagascar. We report new localities for this species, along with locality records for its sister species B. tasymena, including localities where they occur in sympatry, which has never been reported before. We also document evidence for the existence of a colour variant of B. tasymena that is identical to B. erythrodactylus in appearance. We also observed never before documented breeding behaviour in the poorly known B. erythrodactylus, where the male and female in amplexus used a submerged site in a river potentially for oviposition. We also explore why this may be a predator-avoidance strategy considering the presence of aquatic invertebrate predators active near the surface and absence of fully aquatic vertebrate predators, such as fish in headwater stream habitats. Predator-avoidance strategies are a vital component of organismal survival, particularly for amphibians with complex life cycles. Natural history observations are key to revealing such strategies and behaviour, and they form the basis of evolutionary biology and is also fundamental for conservation management.

KEYWORDS:

• arboreal frog
• breeding behaviour
• colour variant
• conservation management
• endemic species
• evolutionary biology
• invertebrate predators
• Mantellidae
• range extension
• sympatry

Acknowledgements

We thank the Malagasy authorities for approving research permits (N°298/13/MEF/SG/DGF/DCB.SAP/SCBSE, N°303/14/MEEMF/SG/DGF/DAPT/SCBT, N°329/15/MEEMF/SG/DGF/DAPT/SCBT); specimens were exported under permits: N°017N-EV01/MG14, N°055N-EA02/MG15, N°041N-EA01/MG16. We also thank Zo Andriampenomanana and the organisation MICET for logistics assistance for acquiring permits, transportation, and other logistics. Finally, we are grateful to three reviewers whose suggestions helped enhance our draft manuscript.