Extreme Eye Projection in the Male Weevil Exechesops leucopis (Coleoptera: Anthribidae): Its Effect on Intrasexual Behavioral Interferences

Abstract

Fungus weevils, Exechesops leucopis (Anthribidae), are sexually dimorphic in the degree of eye protrusion and antenna elongation. I examined the allometric relationships of eye span, eyestalk length, antenna length, elytra width, and wing length against body size (pronotum width), and their effects on the outcome of male-male combat in the laboratory. Male eye span, eyestalk length, and antenna length indicated positive allometry, while elytra width showed isometry, and wing length showed negative allometry. In male-male combat, males with a larger eye span, antenna length, and body size defeated those with smaller attributes. However, when males fought experimentally males of similar body size, only eye span affected the outcome of combat, independent of body size and antenna length. In the female-female contests, the prior residency was an important determinant of victory the other than any morphological traits.