Energetic benefits of sociality offset the costs of parasitism in a cooperative mammal

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Authors

Lutermann, Heike
Bennett, Nigel Charles
Speakman, John R.
Scantlebury, Michael

Journal Title

Journal ISSN

Volume Title

Publisher

Public Library of Science

Abstract

Sociality and particularly advanced forms of sociality such as cooperative breeding (living in permanent groups with reproductive division of labour) is relatively rare among vertebrates. A suggested constraint on the evolution of sociality is the elevated transmission rate of parasites between group members. Despite such apparent costs, sociality has evolved independently in a number of vertebrate taxa including humans. However, how the costs of parasitism are overcome in such cases remains uncertain. We evaluated the potential role of parasites in the evolution of sociality in a member of the African mole-rats, the only mammal family that exhibits the entire range of social systems from solitary to eusocial. Here we show that resting metabolic rates decrease whilst daily energy expenditure and energy stores (i.e. body fat) increase with group size in social Natal mole rats (Cryptomys hottentotus natalensis). Critically, larger groups also had reduced parasite abundance and infested individuals only showed measurable increases in energy metabolism at high parasite abundance. Thus, in some circumstances, sociality appears to provide energetic benefits that may be diverted into parasite defence. This mechanism is likely to be self-reinforcing and an important factor in the evolution of sociality.

Description

Conceived and designed the experiments: HL MS. Performed the experiments: HL MS. Analyzed the data: HL MS JRS. Contributed reagents/materials/analysis tools: JRS NCB. Wrote the paper: HL MS NCB JRS.

Keywords

Energetic benefits, Costs of parasitism, Cooperative mammal

Sustainable Development Goals

Citation

Lutermann H, Bennett NC, Speakman JR, Scantlebury M (2013) Energetic Benefits of Sociality Offset the Costs of Parasitism in a Cooperative Mammal. PLoS ONE 8(2): e57969. DOI: 10.1371/journal.pone.0057969