Strange parental decisions: fathers of the dyeing poison frog deposit their tadpoles in pools occupied by large cannibals
Parents may increase the probability of offspring survival by choosing suitable rearing sites where risks are as low as possible. Predation and competition are major selective pressures influencing the evolution of rearing site selection. Poison frogs look after their clutches and deposit the newly hatched tadpoles in bodies of water where they remain until metamorphosis. In some species, cannibalism occurs, so parents deposit their tadpoles singly in very small pools. However, cannibalism also occurs in species that deposit tadpoles in larger pools already occupied by heterospecific or conspecific larvae that could be either potential predators or competitors. Here, I test the hypothesis that, given the choice, males of Dendrobates tinctorius would deposit their newly hatched tadpoles in low-risk sites for their offspring. I characterised the pools used by D. tinctorius for tadpole deposition, conducted experiments to determine the larval traits that predict the occurrence of and latency to cannibalism, and tested whether parents deposit their tadpoles in low-risk pools. I found that (1) neither pool capacity nor the presence of other larvae predict the presence/absence or number of tadpoles; (2) cannibalism occurs often, and how quickly it occurs depends on the difference in size between the tadpoles involved; and (3) the likelihood of males depositing their tadpoles in occupied pools increases with the size of the resident tadpole. I suggest that predation/cannibalism is not the only factor that parents assess when choosing deposition sites, and that the presence of larger conspecifics may instead provide information about pool quality and stability.
KeywordsParental care Rearing sites Phytotelmata Cannibalism Competition Poison frog
This study was funded by the CIE at Deakin University (Australia). J. Devillechabrolle provided invaluable field assistance, the staff at Nouragues station helped with logistics and P. Gaucher shared his knowledge on the species. I am grateful to John Endler, Karen Warkentin, Jason Brown and anonymous reviewers for helpful comments that improved the manuscript. Many thanks to Andrés López-Sepulcre and Janne Valkonen for statistical advice, and to the “Darwin” group at the University of Jyväskylä for a fruitful discussion on this work.
This study was done in compliance with local regulations. Research permits were issued by the CNRS-Guyane.
Conflict of interest
There is no conflict of interest with the institution that funded this study.
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