Evidence of parental care as a newly identified reproductive isolating barrier
6 affiliations
- 1Department of Evolution, Ecology and Behavior, School of Integrative Biology University of Illinois Urbana‐Champaign Urbana Illinois USA
- 2Department of Evolution, Ecology, and Organismal Biology University of California, Riverside Riverside California USA
- 3Department of Biology Indiana University Bloomington Indiana USA
- 4Program in Ecology, Evolution and Conservation University of Illinois Urbana‐Champaign Urbana Illinois USA
- 5Carl R. Woese Institute for Genomic Biology University of Illinois Urbana‐Champaign Urbana Illinois USA
- 6Program in Neuroscience University of Illinois Urbana‐Champaign Urbana Illinois USA
Abstract
Variation in behaviour can contribute to reproductive isolation by preventing gene flow among populations.
Here, we tested the novel hypothesis that parental care, when dysregulated, can function as a reproductive isolating mechanism in three‐spined stickleback fish (Gasterosteus aculeatus). In the typical ‘common’ stickleback ecotype, males provide care to their offspring by fanning with their pectoral fins and defending their nest. By contrast, a divergent ‘white’ stickleback ecotype has evolutionarily lost care and disperses embryos into the surrounding environment.
We examined how paternal care from common, white and F1 hybrid fathers influenced offspring survival. We detected no intrinsic incompatibilities in embryos, but F1 hybrid fathers exhibited dysregulated parental care that coincided with decreased survival of parented offspring. The increased offspring mortality may be explained by further dysregulation of feeding and parenting circuitry, as F2 hybrids exhibited significantly higher rates of post‐fertilization filial cannibalism than common or white fathers.
Additionally, despite strong divergence in nesting–building and courtship behaviour, F1 hybrids achieved mating success at a similar rate as male commons and whites, suggesting that prezygotic barriers against hybrids may be weak.
The observed postzygotic isolation, and potentially weak prezygotic isolation in lab‐based studies, suggest that hybridization is likely occurring at low rates in the wild. Population genetic analysis supported this, as low proportions of putative hybrids were detected in sympatric sites.
Together, these results may help explain why genetic divergence between these phenotypically distinct ecotypes is low and provide evidence that dysregulated parental behaviour can act as a newly discovered postzygotic reproductive isolating barrier.
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BibTeX
@article{behrens2026evidence,
title = {{Evidence of parental care as a newly identified reproductive isolating barrier}},
author = {Colby Behrens and Meghan F. Maciejewski and Alexandra Sumarli and Gina Lucas and German Lagunas‐Robles and Kieran Samuk and Alison M. Bell},
journal = {The Journal of Animal Ecology},
year = {2026},
month = sep,
doi = {10.1111/1365-2656.70348},
url = {https://doi.org/10.1111/1365-2656.70348},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Evidence of parental care as a newly identified reproductive isolating barrier
AU - Colby Behrens
AU - Meghan F. Maciejewski
AU - Alexandra Sumarli
AU - Gina Lucas
AU - German Lagunas‐Robles
AU - Kieran Samuk
AU - Alison M. Bell
PY - 2026
DA - 2026/09/23
JO - The Journal of Animal Ecology
DO - 10.1111/1365-2656.70348
UR - https://doi.org/10.1111/1365-2656.70348
AB - Variation in behaviour can contribute to reproductive isolation by preventing gene flow among populations. Here, we tested the novel hypothesis that parental care, when dysregulated, can function as a reproductive isolating mechanism in three‐spined stickleback fish (Gasterosteus aculeatus). In the typical ‘common’ stickleback ecotype, males provide care to their offspring by fanning with their pectoral fins and defending their nest. By contrast, a divergent ‘white’ stickleback ecotype has evolutionarily lost care and disperses embryos into the surrounding environment. We examined how paternal care from common, white and F1 hybrid fathers influenced offspring survival. We detected no intrinsic incompatibilities in embryos, but F1 hybrid fathers exhibited dysregulated parental care that coincided with decreased survival of parented offspring. The increased offspring mortality may be explained by further dysregulation of feeding and parenting circuitry, as F2 hybrids exhibited significantly higher rates of post‐fertilization filial cannibalism than common or white fathers. Additionally, despite strong divergence in nesting–building and courtship behaviour, F1 hybrids achieved mating success at a similar rate as male commons and whites, suggesting that prezygotic barriers against hybrids may be weak. The observed postzygotic isolation, and potentially weak prezygotic isolation in lab‐based studies, suggest that hybridization is likely occurring at low rates in the wild. Population genetic analysis supported this, as low proportions of putative hybrids were detected in sympatric sites. Together, these results may help explain why genetic divergence between these phenotypically distinct ecotypes is low and provide evidence that dysregulated parental behaviour can act as a newly discovered postzygotic reproductive isolating barrier.
SN - 0021-8790
SN - 1365-2656
ER -