Evolution of a flexible rule for foraging that copes with environmental variation
Higginson, Andrew D.
Oxford University Press
© 2015 Current Zoology
Models of adaptive behaviour typically assume that animals behave as though they have highly complex, detailed strategies for making decisions. In reality, selection favours the optimal balance between the costs and benefits of complexity. Here we investigate this trade-off for an animal that has to decide whether or not to forage for food - and so how much energy reserves to store - depending on the food availability in its environment. We evolve a decision rule that controls the target reserve level for different ranges of food availability, but where increasing complexity is costly in that metabolic rate increases with the sensitivity of the rule. The evolved rule tends to be much less complex than the optimal strategy but performs almost as well, while being less costly to implement. It achieves this by being highly sensitive to changing food availability at low food abun-dance - where it provides a close fit to the optimal strategy - but insensitive when food is plentiful. When food availability is high, the target reserve level that evolves is much higher than under the optimal strategy, which has implications for our under-standing of obesity. Our work highlights the important principle of generalisability of simple decision-making mechanisms, which enables animals to respond reasonably well to conditions not directly experienced by themselves or their ancestors.
This work was supported by the European Research Council (Advanced Grant 250209 to A.I.H.) and a College for Life Sciences Fellowship at the Wissenschaftskolleg zu Berlin awarded to A.D.H.
This is the final version of the article. It first appeared from Oxford University Press via http://www.currentzoology.org/paperdetail.asp?id=12437
Current Zoology, 2015, Vol. 61 (2), pp. 303 - 312