Can mechanism help explain insect host choice?
Article first published online: 6 JAN 2012
© 2012 The Author. Journal of Evolutionary Biology © 2012 European Society For Evolutionary Biology
Journal of Evolutionary Biology
Volume 25, Issue 2, pages 244–251, February 2012
How to Cite
CUNNINGHAM, J. P. (2012), Can mechanism help explain insect host choice?. Journal of Evolutionary Biology, 25: 244–251. doi: 10.1111/j.1420-9101.2011.02435.x
- Issue published online: 12 JAN 2012
- Article first published online: 6 JAN 2012
- Received 23 August 2011; revised 9 November 2011; accepted 10 November 2011
- antennal lobe;
- host selection;
- information processing;
Evolutionary theory predicts that herbivorous insects should lay eggs on plants in a way that reflects the suitability of each plant species for larval development. Empirical studies, however, often fail to find any relationship between an adult insect’s choice of host–plant and offspring fitness, and in such cases, it is generally assumed that other ‘missing’ factors (e.g. predation, host–plant abundance, learning and adult feeding sites) must be contributing to overall host suitability. Here, I consider an alternative theory – that a fitness cost inherent in the olfactory mechanism could constrain the evolution of insect host selection. I begin by reviewing current knowledge of odour processing in the insect antennal lobe with the aid of a simple schematic: the aim being to explain the workings of this mechanism to scientists who do not have prior knowledge in this field. I then use the schematic to explore how an insect’s perception of host and non-host odours is governed by a set of processing rules, or algorithm. Under the assumptions of this mechanistic view, the perception of every plant odour is interrelated, and seemingly bad host choices can still arise as part of an overall adaptive behavioural strategy. I discuss how an understanding of mechanism can improve the interpretation of theoretical and empirical studies in insect behaviour and evolution.