Rojas: Why a male poison frog (Dendrobates tinctorius) leaves his newborn in water inhabited by larger, cannibalistic tadpoles?

Bibiana Rojas studied in her recently published research "Strange parental decisions: fathers of the dyeing poison Poison frogfrog deposit their tadpoles in pools occupied by large cannibal" poison frogs' behaviour where poison frogs carry their tadpoles to pools of water. Frogs prefer water inhabited by larger, cannibalistic tadpoles which intuitive would be expected to be poor habitats for tadpoles. They face a risk of being eaten by a larger tadpole. Poison frogs may choose these already inhabited pools of water because these pools will most likely offer the proper conditions for a frog to grow. That is they won't dry up. Reed more here.

Abstract of the original paper:
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.
Behavioral Ecology and Sociobiology 2014 DOI:10.1007/s00265-013-1670-y