Bioenergetics of behavioural strategies in desert income and capital breeders

Income and capital breeders adopt distinct reproductive strategies based on available resources. Income breeders rely on resources currently accessible in the environment, while capital breeders rely on stored resources. Bioenergetic performance and trade-off models offer predictions about how energy turnover determines animal energy budgets and behavioural decisions.The performance model proposes that high maintenance cost signals high energy turnover, supporting behaviours with high energy demands.Trade-off models,on the other hand, are focused on allocation and compensation between costly behaviours and physiological maintenance. We studied bioenergetics and personality traits of two sympatric rodent species representing distinct reproductive strategies in a harsh desert environment. We found that putative income breeder, roaming forager African hammada jerboa, may operate under performance bioenergetic mechanisms, where high maintenance costs correlate positively with repeatable exploratory behaviour. In contrast, a capital breeder, sedentary hoarder Shaw’s jird, operates under allocation bioenergetic mechanisms, where maintenance cost negatively correlates with the same behaviour. Integrating bioenergetics into the the income-capital breeder concept provides proximate and adaptive predictions about how diversity of reproductive strategies is maintained in resource-limited environments.