2026-10-15T09:11:26Z https://oai.datacite.org/oai

doi:10.5061/dryad.ng20q 2026-01-27T09:21:06Z DRYAD DRYAD.DRYAD

Data from: Variation in offspring size with birth order in placental fish: a role for asymmetric sibling competition? Schrader, Matthew Travis, Joseph Dryad 2011 Submitted: 2011-07-21T20:20:50Z Issued: 2011-07-22T15:51:33Z Available: 2011-07-22T15:51:33Z doi:10.1111/j.1558-5646.2011.01422.x size at birth Heterandria formosa Placenta sibling competition Asymmetric sibling competition arises when siblings with different competitive abilities share a limited resource. Such competition occurs in species with postnatal parental care and may also occur when mothers provision embryos between fertilization and birth (matrotrophy). We hypothesized that the combination of matrotrophy and the simultaneous provisioning of embryos in different stages of development (superfetation) leads to asymmetric competition between sibling embryos. Moreover, we expect the intensity of this competition to increase with the level of superfetation as high levels of superfetation result in greater temporal overlap between broods. This hypothesis predicts that offspring from early broods, which predominantly compete with less developed siblings, will be larger at birth than offspring from later broods, which experience competition from more and less developed siblings. Data on offspring size at birth from two populations of the highly matrotrophic fish, Heterandria formosa, and similar studies of poeciliid fish spanning a range of life histories are consistent with our hypothesis. Together these results suggest that sibling competition is a direct consequence of the evolution of matrotrophy and superfetation in poeciliid fish. Schrader_and_Travis_Evol_2011.txt en Dataset dataset Creative Commons Zero v1.0 Universal https://creativecommons.org/publicdomain/zero/1.0/legalcode