Cooperative interactions within the family enhance the capacity for evolutionary change in body size
Nature Ecology and Evolution
Nature Publishing Group
© 2017 Macmillan Publishers Limited, part of Springer Nature. All rights reserved.
Reason for embargo
Classical models of evolution seldom predict the rate at which populations evolve in the wild. One explanation is that the social environment affects how traits change in response to natural selection. Here we determine how social interactions between parents and offspring, and among larvae, influence the response to experimental selection on adult size. Our experiments focus on burying beetles (Nicrophorus vespilloides), whose larvae develop within a carrion nest. Some broods exclusively self-feed on the carrion, while others are also fed by their parents. We found that populations responded to selection for larger adults, but only when parents cared for their offspring. We also found that populations responded to selection for smaller adults, but only by removing parents and causing larval interactions to exert more influence on eventual adult size. Comparative analyses revealed a similar pattern: evolutionary increases in species size within the genus Nicrophorus are associated with the obligate provision of care. Combining our results with previous studies, we suggest that cooperative social environments enhance the response to selection, whereas excessive conflict can prevent a response to further directional selection.
This project was funded by a European Research Council grant (310785_Baldwinian_Beetles), and a Royal Society Wolfson Research Merit Award, both to R.M.K. We are very grateful to S.-J. Sun and D. Howard for providing unpublished information about other burying beetle species, and to C. Creighton for discussion. We thank S. Herce Castañón for help with MATLAB; M. Barclay and R. Booth from the Natural History Museum, London for their help with the beetle collections; and K. MacLeod and P. Lawrence for commenting on earlier drafts. A. Backhouse, S. Aspinall and C. Swannack maintained the beetles while A. Attisano, E. Briolat, A. Duarte and O. de Gasperin helped in the laboratory.
This is the author accepted manuscript. The final version is available from Nature Publishing Group via the DOI in this record.
Vol. 1, Art. No. 0178 (2017)