TY - JOUR
T1 - Evolution of sex differences in cooperation can be explained by trade-offs with dispersal
AU - Capilla-Lasheras, Pablo
AU - Bircher, Nina
AU - Brown, Antony M.
AU - Harrison, Xavier
AU - Reed, Thomas
AU - York, Jennifer E.
AU - Cram, Dominic L.
AU - Rutz, Christian
AU - Walker, Lindsay
AU - Naguib, Marc
AU - Young, Andrew J.
N1 - Data Availability Statement: All R scripts and datasets needed to reproduce the analyses presented in this paper are available at: https://doi.org/10.5281/zenodo.13623047.
Funding information: The long-term field study was funded principally by BBSRC David Phillips and NERC Blue Skies Research Fellowships to AJY (BB/H022716/1 and NE/E013481/1) and PC-L was supported by a BBSRC-funded PhD studentship (BB/M009122/1). A BBSRC David Phillips Research Fellowship to CR (BB/G023913/1 and BB/G023913/2) funded the Encounternet equipment. NB was supported by an ALW-NWO open competition grant (ALWOP 824.15.012) to MN. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
PY - 2024/10/24
Y1 - 2024/10/24
N2 - Explaining the evolution of sex differences in cooperation remains a major challenge. Comparative studies highlight that offspring of the more philopatric sex tend to be more cooperative within their family groups than those of the more dispersive sex but we do not understand why. The leading “Philopatry hypothesis” proposes that the more philopatric sex cooperates more because their higher likelihood of natal breeding increases the direct fitness benefits of natal cooperation. However, the “Dispersal trade-off hypothesis” proposes that the more dispersive sex cooperates less because preparations for dispersal, such as extra-territorial prospecting, trade-off against natal cooperation. Here, we test both hypotheses in cooperatively breeding white-browed sparrow weavers (Plocepasser mahali), using a novel high-resolution automated radio-tracking method. First, we show that males are the more dispersive sex (a rare reversal of the typical avian sex difference in dispersal) and that, consistent with the predictions of both hypotheses, females contribute substantially more than males to cooperative care while within the natal group. However, the Philopatry hypothesis cannot readily explain this female-biased cooperation, as females are not more likely than males to breed within their natal group. Instead, our radio-tracking findings support the Dispersal trade-off hypothesis: males conduct pre-dispersal extra-territorial prospecting forays at higher rates than females and prospecting appears to trade-off against natal cooperation. Our findings thus highlight that the evolution of sex differences in cooperation could be widely attributable to trade-offs between cooperation and dispersal; a potentially general explanation that does not demand that cooperation yields direct fitness benefits.
AB - Explaining the evolution of sex differences in cooperation remains a major challenge. Comparative studies highlight that offspring of the more philopatric sex tend to be more cooperative within their family groups than those of the more dispersive sex but we do not understand why. The leading “Philopatry hypothesis” proposes that the more philopatric sex cooperates more because their higher likelihood of natal breeding increases the direct fitness benefits of natal cooperation. However, the “Dispersal trade-off hypothesis” proposes that the more dispersive sex cooperates less because preparations for dispersal, such as extra-territorial prospecting, trade-off against natal cooperation. Here, we test both hypotheses in cooperatively breeding white-browed sparrow weavers (Plocepasser mahali), using a novel high-resolution automated radio-tracking method. First, we show that males are the more dispersive sex (a rare reversal of the typical avian sex difference in dispersal) and that, consistent with the predictions of both hypotheses, females contribute substantially more than males to cooperative care while within the natal group. However, the Philopatry hypothesis cannot readily explain this female-biased cooperation, as females are not more likely than males to breed within their natal group. Instead, our radio-tracking findings support the Dispersal trade-off hypothesis: males conduct pre-dispersal extra-territorial prospecting forays at higher rates than females and prospecting appears to trade-off against natal cooperation. Our findings thus highlight that the evolution of sex differences in cooperation could be widely attributable to trade-offs between cooperation and dispersal; a potentially general explanation that does not demand that cooperation yields direct fitness benefits.
UR - http://www.scopus.com/inward/record.url?scp=85207362788&partnerID=8YFLogxK
U2 - 10.1371/journal.pbio.3002859
DO - 10.1371/journal.pbio.3002859
M3 - Article
VL - 22
JO - PLoS Biology
JF - PLoS Biology
SN - 1545-7885
IS - 10
M1 - e3002859
ER -