In his documentary, Life, David Attenborough explores the mysteries and complexities of life by observing a variety of land and marine animals. In Season 1 episode 1, Attenborough addresses the various “challenges of life” that animals face and mentioned, in many cases, parental care and contributions toward their offspring. Of the many examples, the Oophaga pumilio, more commonly known as the strawberry poison arrow frog, seems to have one of the most extensive and committed roles towards their offspring. The strawberry poison arrow frog is a member of the Dendrobatoidea (poisonous frog) superfamily and is no larger than a human fingernail [3]. This specific frog is located in Central America around Nicaragua to Panama [1] and it is due to their small size that makes their feats and commitment to their offspring most impressive.
The members of the Dendrobatoidea superfamily are known to share the trait of transporting their eggs from each rearing location as they move from terrestrial locations to aquatic sites in order to provide their offspring with a safe home that allows them to develop into adults [3]. In the case of Oophaga pumilio, the mother frog must carry each tadpole on her back and ascend a tall tree to look for a bromeliad, a plant which has a pool of water at its center, to make the new home for the developing tadpole: a nursery pool. The feat is equivalent to a human mother climbing the empire state building with a baby on her back, and she does not just accomplish it once. She must find a different pool for each off her tadpoles, carrying them one by one. Interestingly enough, the mother’s efforts for her offspring do not simply end there. As the new nursery pools do not have any source of food, she must lay an unfertilized egg (trophic egg) to feed each tadpole. Thus, over the course of the next six weeks, the mother must provide an egg to each tadpole every 1 – 8 days, covering almost half a mile over just two weeks [2].
Research has indicated that these trophic eggs are important for the survival of tadpoles into adulthood, thereby validating the efforts the mother puts in weekly to make the journey and feed each of her offspring [1]. The value of the trophic eggs may be attributed to the discovery that they are a provision of alkaloid based chemical defenses for the tadpole against predators [4]. Thus, the efforts of the mother frog and the heavy costs to care for her offspring are not gone to waste [3]. The strawberry poison arrow frog is an exemplary example of the care and energy parents put in for their children.
By Wendy Zhan and Hyun Seong Seo
Life, Season 1, Episode 1 (Challenges of Life), starting at 36:07
References
- Dugas M, Wamelink C, Killius A, C Richards-Zawacki. 2016. Parental care is beneficial for offspring, costly for mothers, and limited by family size in an egg-feeding frog, Behavioral Ecology, 27(2): 476–483
- Stynoski JL. 2012. Behavioral ecology of parental care in a dendrobatid frog (Oophaga pumilio). Open Access Dissertations. 755.
- Pašukonis A, Trenkwalder K, Ringler M, Ringler E, Mangione R, Steininger J, Warrington I, W Hödl. 2016. The significance of spatial memory for water finding in a tadpole-transporting frog, Animal Behaviour 116: 89-98.
- Stynoski, JL, Torres-Mendoza, Y, Sasa-Marin, M and Saporito, RA. 2014. Evidence of maternal provisioning of alkaloid‐based chemical defenses in the strawberry poison frog Oophaga pumilio. Ecology 95: 587-593.
The Evolution of Planet Earth 