Poison frog tadpoles seek parental transportation to escape their cannibalistic siblings

• Published in: Journal of zoology (1987) Vol. 303; no. 2; pp. 83 - 89
• Main Authors: Schulte, L. M., Mayer, M.
• Format: Journal Article
• Language: English
• Published: London Blackwell Publishing Ltd 01.10.2017
• Subjects: Amphibiotic species; begging behaviours; Biological competition; Cannibalism; Competition; Cues; Dendrobatidae; Food; Frogs; Hatching; Males; Offspring; Ova; Parent-offspring interactions; Parental behaviour; parental care; Parents; poison frog; Ranitomeya variabilis; sibling competition; Siblings; Tactile; Transportation; Visual perception; Visual stimuli
• ISSN: 0952-8369; 1469-7998
• DOI: 10.1111/jzo.12472

Parental care is a limited resource which in many species is acquired by the offspring through begging behaviours and often causes competition between siblings. The Neotropical poison frog Ranitomeya variabilis provides a very specific form of parental care: because its tadpoles are cannibalistic males usually separate them from their siblings after hatching by transporting them singly to small water bodies. However, in some cases parents do not transport their tadpoles but let them all hatch into the same pool. Here, we investigate if abandoned tadpoles of R. variabilis actively seek parental care in form of transportation. We conducted experiments where tadpoles of the same clutch were presented with con‐ and heterospecific frogs, and both moving and non‐moving frog models. Our results revealed that abandoned tadpoles actively approached all frogs and sometimes even climbed onto their backs. We suggest that this tadpole behaviour may function to allow tadpoles to escape sibling competition and cannibalism. Being the first (and possibly the only one) to leave the shared pool should give a tadpole a high survival advantage over its brood‐mates. We further found that tadpoles did not approach artificial models, suggesting that these where either not natural enough or that tadpoles do not recognize frogs by visual or tactile cues but might use chemical or multiple stimuli. The latter is also the case in related egg‐feeding species where tadpoles beg for food. We therefore discuss our results in relation to potential begging behaviours, as well as fixed action patterns and parent–offspring conflict, being potential questions opening up for future examinations regarding our findings. Poison frog tadpoles of the species Ranitomeya variabilis, unless separately transported elsewhere by their parents, hatch together with their cannibalistic siblings into small plant pools. Our behavioural tests revealed that such tadpoles were highly attracted not only to conspecific but all frogs entering their pools, followed them and tried to climb onto their backs, probably in order to escape their siblings. Moved and motionless frog models, however, did not trigger the same behaviour, assuming that they did not emit the right cues to attract tadpoles.