Maternal costs in offspring production affect investment rules in joint rearing
Russell, Andrew F
Oxford University Press
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Savage, J., Russell, A. F., & Johnstone, R. (2012). Maternal costs in offspring production affect investment rules in joint rearing. Behavioral Ecology, 24 750-758. https://doi.org/10.1093/beheco/ars203
When multiple individuals contribute to rearing the same oﬀspring, conﬂict is expected to occur over the relative amounts invested by each carer. Existing models of biparental care suggest that this conﬂict should be resolved by partially compensating for changes by co-investors, but this has yet to be explicitly modeled in cooperative breeders over a range of carer numbers. In addition, existing models of biparental and cooperative care ignore potential variation in both the relative costs of oﬀspring production to mothers and in maternal allocation decisions. If mothers experience particularly high costs during oﬀspring production, this might be expected to aﬀect their investment strategies during later oﬀspring care. Here we show using a game-theoretical model that a range of investment tactics can result depending on the number of carers and the relative costs to the mother of the diﬀerent stages within the breeding attempt. Additional carers result in no change in investment by individuals when production costs are low, as mothers can take advantage of the greater potential investment by increasing oﬀspring number; however this tactic ultimately results in a decrease in care delivered to each oﬀspring. Conversely, when production costs prevent the mother from increasing oﬀspring number, our model predicts that other individuals should partially compensate for additional carers and hence oﬀspring should each receive a greater amount of care. Our results reinforce the importance of considering investment across all stages in a breeding attempt, and provide some explanatory power for the variation in investment rules observed across cooperative species.
bi-parental care, cooperative breeding, game theory, incomplete compensation, maternal eﬀects, sealed-bid
This work was supported by a Natural Environment Research Council studentship to JLS, and by a Royal Society University Research Fellowship to AFR.
External DOI: https://doi.org/10.1093/beheco/ars203
This record's URL: https://www.repository.cam.ac.uk/handle/1810/245537