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Published January 13, 2016 | public
Journal Article

Lifespan behavioural and neural resilience in a social insect

Abstract

Analyses of senescence in social species are important to understanding how group living influences the evolution of ageing in society members. Social insects exhibit remarkable lifespan polyphenisms and division of labour, presenting excellent opportunities to test hypotheses concerning ageing and behaviour. Senescence patterns in other taxa suggest that behavioural performance in ageing workers would decrease in association with declining brain functions. Using the ant Pheidole dentata as a model, we found that 120-day-old minor workers, having completed 86% of their laboratory lifespan, showed no decrease in sensorimotor functions underscoring complex tasks such as alloparenting and foraging. Collaterally, we found no age-associated increases in apoptosis in functionally specialized brain compartments or decreases in synaptic densities in the mushroom bodies, regions associated with integrative processing. Furthermore, brain titres of serotonin and dopamine—neuromodulators that could negatively impact behaviour through age-related declines—increased in old workers. Unimpaired task performance appears to be based on the maintenance of brain functions supporting olfaction and motor coordination independent of age. Our study is the first to comprehensively assess lifespan task performance and its neurobiological correlates and identify constancy in behavioural performance and the absence of significant age-related neural declines.

Additional Information

© 2016 The Author(s) Published by the Royal Society. Received: 28 October 2015. Accepted: 25 November 2015. Published 6 January 2016. Prof. Rhondda Jones and Dr Iulian Ilies¸ provided valuable statistical advice. We thank Drs Wulfila Gronenberg, Karen Warkentin and Kimberly McCall for their critical reading of earlier drafts of the manuscript and technical insights. Two anonymous reviewers provided constructive comments. Positive controls for TUNEL were adapted from procedures developed by Dr J. I. Etchegaray.

Additional details

Created:
August 20, 2023
Modified:
October 17, 2023