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High host‐plant nitrogen content: a prerequisite for the evolution of ant–caterpillar mutualism?
Author(s) -
PELLISSIER L.,
RASMANN S.,
LITSIOS G.,
FIEDLER K.,
DUBUIS A.,
POTTIER J.,
GUISAN A.
Publication year - 2012
Publication title -
journal of evolutionary biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.289
H-Index - 128
eISSN - 1420-9101
pISSN - 1010-061X
DOI - 10.1111/j.1420-9101.2012.02555.x
Subject(s) - biology , lycaenidae , mutualism (biology) , caterpillar , host (biology) , myrmecophily , ecology , insect , exaptation , butterfly , ant , larva , evolutionary biology
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.