Entomophagy, behavior, and elongated thoracic legs in the myrmecophilous neotropical butterfly Alesa amesis (Riodinidae)

Entomophagy in the riodinid butterfly tribe Eurybiini Is demonstrated for t he first time. Alesa amesis caterpillars and adults possess behavioral and morphological traits for feeding on Homoptera nymphs, and oviposition by A. amesis females is mediated by the combined presence of Camponotus femoratu s ants and homopteran nymphs. Caterpillars are entirely entomophagous, and do not eat plant tissues. Alesa amesis caterpillars have distinct behaviors for feeding on their prey and for soliciting and drinking honeydew secreti ons from homopteran nymphs. The leg lengths of entomophagous Alesa caterpil lars are shown to be longer than phytophagous relatives. The legs of Alesa are used for prey handling and soliciting honeydew secretions. We suggest t hat elongation of the thoracic legs has been a general consequence of entom ophagy in butterfly caterpillars. This study clarifies our understanding of A. amesis and its interactions with multiple species, and points to behavi oral and morphological traits important to interpreting the evolution of en tomophagy among caterpillars. Our observations establish the likelihood tha t other members of Eurybiini may be entomophagous, and suggest that entomop hagy may have evolved independently among the Nymphidiini and Eurybiini.