Food intake of fruit-feeding butterflies: evidence for adaptive variation in proboscis morphology

Abstract

Adult butterflies feed from a variety of substrates and have appropriate adaptations. We examined proboscis morphology in a community of fruit-feeding butterflies (Nymphalidae) in a tropical forest in Uganda. These data were supplemented with behavioural observations and measurements of intake rate on natural and artificial substrates. We found no sexual dimorphism in proboscis morphology even though puddling behaviour is usually performed by males. Two main feeding techniques could be distinguished on the basis of behaviour and morphology: the piercing technique, typically found in Charaxinae, and the sweeping technique employed by both Nymphalinae and Satyrinae. These techniques, distinguished in previous studies, are described in more detail and their relative efficiencies are discussed in the context of sexual dimorphism, food-choice and life history evolution.