High host-plant nitrogen content: a prerequisite for the evolution of ant–caterpillar mutualism?
Article first published online: 21 JUN 2012
© 2012 The Authors. Journal of Evolutionary Biology © 2012 European Society For Evolutionary Biology
Journal of Evolutionary Biology
Volume 25, Issue 8, pages 1658–1666, August 2012
How to Cite
PELLISSIER, L., RASMANN, S., LITSIOS, G., FIEDLER, K., DUBUIS, A., POTTIER, J. and GUISAN, A. (2012), High host-plant nitrogen content: a prerequisite for the evolution of ant–caterpillar mutualism?. Journal of Evolutionary Biology, 25: 1658–1666. doi: 10.1111/j.1420-9101.2012.02555.x
- Issue published online: 16 JUL 2012
- Article first published online: 21 JUN 2012
- Received 27 November 2011; revised 18 April 2012; accepted 27 April 2012
- host-plant quality;
- niche breadth;
- plant–herbivore interaction
The amount of nitrogen required to complete an insect’s life cycle may vary greatly among species that have evolved distinct life history traits. Myrmecophilous caterpillars in the Lycaenidae family produce nitrogen-rich exudates from their dorsal glands to attract ants for protection, and this phenomenon has been postulated to shape the caterpillar’s host-plant choice. Accordingly, it was postulated that evolution towards myrmecophily in Lycaenidae is correlated with the utilization of nitrogen-rich host plants. Although our results were consistent with the evolutionary shifts towards high-nutrient host plants serving as exaptation for the evolution of myrmecophily in lycaenids, the selection of nitrogen-rich host plants was not confined to lycaenids. Butterfly species in the nonmyrmecophilous family Pieridae also preferred nitrogen-rich host plants. Thus, we conclude that nitrogen is an overall important component in the caterpillar diet, independent of the level of myrmecophily, as nitrogen can enhance the overall insect fitness and survival. However, when nitrogen can be obtained through alternative means, as in socially parasitic lycaenid species feeding on ant brood, the selective pressure for maintaining the use of nutrient-rich host plants is relaxed, enabling the colonization of nitrogen-poor host plants.