No task specialization among helpers in Damaraland mole-rats
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Date
Authors
Thorley, Jack
Mendonca, Rute
Vullioud, Philippe
Torrents-Tico, Miquel
Zottl, Markus
Gaynor, David
Clutton-Brock, Tim H.
Journal Title
Journal ISSN
Volume Title
Publisher
Elsevier Masson
Abstract
The specialization of individuals in specific behavioural tasks is often attributed either to irreversible
differences in development, which generate functionally divergent cooperative phenotypes, or to agerelated
changes in the relative frequency with which individuals perform different cooperative activities;
both of which are common in many insect caste systems. However, contrasts in cooperative
behaviour can take other forms and, to date, few studies of cooperative behaviour in vertebrates have
explored the effects of age, adult phenotype and early development on individual differences in cooperative
behaviour in sufficient detail to discriminate between these alternatives. Here, we used multinomial
models to quantify the extent of behavioural specialization within nonreproductive Damaraland
mole-rats, Fukomys damarensis, at different ages. We showed that, although there were large differences
between individuals in their contribution to cooperative activities, there was no evidence of individual
specialization in cooperative activities that resembled the differences found in insect societies with
distinct castes where individual contributions to different activities are negatively related to each other.
Instead, individual differences in helping behaviour appeared to be the result of age-related changes in
the extent to which individuals committed to all forms of helping. A similar pattern is observed in
cooperatively breeding meerkats, Suricata suricatta, and there is no unequivocal evidence of caste differentiation
in any cooperative vertebrate. The multinomial models we employed offer a powerful
heuristic tool to explore task specialization and developmental divergence across social taxa and provide
an analytical approach that may be useful in exploring the distribution of different forms of helping
behaviour in other cooperative species.
Description
Keywords
Bathyergidae, Eusociality, Social niche specialization, Task allocation, Totipotency, Trade-offs
Sustainable Development Goals
Citation
Thorley. J., Mendonça, R., Vullioud, P. et al. 2018, 'No task specialization among helpers in Damaraland mole-rats', Animal Behaviour, vol. 143, pp. 9-24.