Variation in growth of Damaraland mole-rats is explained by competition rather than by functional specialization for different tasks
Royal Society Publishing
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Zöttl, M., Thorley, J., Gaynor, D., Bennett, N., & Clutton-Brock, T. (2016). Variation in growth of Damaraland mole-rats is explained by competition rather than by functional specialization for different tasks. Biology Letters, 12 (12. 20160820)https://doi.org/10.1098/rsbl.2016.0820
In some eusocial insect societies, adaptation to the division of labour results in multimodal size variation among workers. It has been suggested that variation in size and growth among non-breeders in naked and Damaraland mole-rats may similarly reflect functional divergence associated with different cooperative tasks. However, it is unclear whether individual growth rates are multimodally distributed (as would be expected if variation in growth is associated with specialization for different tasks) or whether variation in growth is unimodally distributed, and is related to differences in the social and physical environment (as would be predicted if there are individual differences in growth but no discrete differences in developmental pathways). Here, we show that growth trajectories of non-breeding Damaraland mole-rats vary widely, and that their distribution is unimodal, contrary to the suggestion that variation in growth is the result of differentiation into discrete castes. Though there is no evidence of discrete variation in growth, social factors appear to exert important effects on growth rates and age-specific size, which are both reduced in large social groups.
growth, division of labour, cooperative breeding, eusociality
This study was funded by an European Research Council grant to THCB (294494).
European Research Council (294494)
External DOI: https://doi.org/10.1098/rsbl.2016.0820
This record's URL: https://www.repository.cam.ac.uk/handle/1810/262546