Summary

Since the seminal work of Davies in the late 1970s, territorial male butterfly contests have offered an excellent system for the empirical scrutiny of contest theories, particularly residency-related game-theoretic principles. Because butterflies lack the obvious morphological traits usually associated with animal aggression, their extended and often spectacular aerial duels both defy simple explanation and provide unique empirical opportunities. Residency win rates often approach 100% in this group, which, coupled with the apparently ‘weaponless’ nature of butterflies and the non-contact nature of their disputes, provided the early impetus for tests of the ‘bourgeois’ resident-wins model of contest resolution. Subsequent work has emphasised how potential residency-related RHP asymmetries, including those relating to temporally variable biophysical parameters, such as body temperature, may instead contribute to high rates of residents winning. The balance of empirical work in this group, however, suggests that morphological and/or biophysical factors bear little relevance to content settlement. Contest participation is not obviously mediated by energetics, which contrasts markedly and interestingly with the aerial wars of attrition of other insects, such as odonates. More recent approaches to understanding butterfly contest resolution have led to an appreciation of how life history-level factors, such as ageing and changes in residual reproductive value, may influence aggressive motivation and subsequent levels of contest participation. These principles apply generally, thereby placing butterfly contests as a potentially important system for the empirical investigation of the broader life-historical context of animal aggression.