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The number of offspring parents rear varies considerably among closely related lineages, individuals, and even reproductive events by one individual. Constraints can come at any point, from the costs of producing a large clutch to the cost of caring for a large brood of dependent young. We report here on observations of the early phase of a reproductive cycle in a captive colony of Oophaga pumilio, a poison frog with offspring entirely dependent on maternally provisioned trophic eggs. We tracked reproductive clutches, and found that while clutch and egg size were variable, neither predicted the success of a clutch; there was also no evidence of a trade-off between clutch and egg size. Larger eggs did, however, produce larger tadpoles, and when parents transported only a subset of the brood to nurseries, the tadpoles they moved were larger than the ones they did not. Adaptive adjustment of parental investment is a key life-history trait, and a complete accounting of the way families are constructed is key to understanding the evolution of parental care, parental favoritism, and cooperation and conflict among closely related individuals.
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Aposematism facilitates the diversification of parental care strategies in poison frogs
Abstract Many organisms have evolved adaptations to increase the odds of survival of their offspring. Parental care has evolved several times in animals including ectotherms. In amphibians, ~ 10% of species exhibit parental care. Among these, poison frogs (Dendrobatidae) are well-known for their extensive care, which includes egg guarding, larval transport, and specialized tadpole provisioning with trophic eggs. At least one third of dendrobatids displaying aposematism by exhibiting warning coloration that informs potential predators about the presence of defensive skin toxins. Aposematism has a central role in poison frog diversification, including diet specialization, and visual and acoustic communication; and it is thought to have impacted their reproductive biology as well. We tested the latter association using multivariate phylogenetic methods at the family level. Our results show complex relationships between aposematism and certain aspects of the reproductive biology in dendrobatids. In particular, aposematic species tend to use more specialized tadpole-deposition sites, such as phytotelmata, and ferry fewer tadpoles than non-aposematic species. We propose that aposematism may have facilitated the diversification of microhabitat use in dendrobatids in the context of reproduction. Furthermore, the use of resource-limited tadpole-deposition environments may have evolved in tandem with an optimal reproductive strategy characterized by few offspring, biparental care, and female provisioning of food in the form of unfertilized eggs. We also found that in phytotelm-breeders, the rate of transition from cryptic to aposematic phenotype is 17 to 19 times higher than vice versa. Therefore, we infer that the aposematism in dendrobatids might serve as an umbrella trait for the evolution and maintenance of their complex offspring-caring activities.
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- Award ID(s):
- 2016372
- PAR ID:
- 10383697
- Publisher / Repository:
- Nature Publishing Group
- Date Published:
- Journal Name:
- Scientific Reports
- Volume:
- 11
- Issue:
- 1
- ISSN:
- 2045-2322
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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