Do Long Sexy Legs Matter: Conflict in the Waitomo Cave Weta (Pachyrhamma waitomoensis)

Abstract

New Zealand cave weta of the family Rhaphidophoridae are notable for their long legs, and anecdotal evidence suggests that the proportionally larger hind legs of males are utilised during male-male combat in the acquisition and defence of mates. My research seeks to understand the scaling of Pachyrhamma waitomoensis, and determine if variation in male competitive success relates to body size and/or leg length. Adult cave weta are individually marked, and a range of morphological traits measured, allowing subsequent observation of known individuals and their competitive success. Focal observations allow determination of the individuals who experience most success in fighting, and how this relates to their morphology. Weta form an important part of New Zealand cave forest fauna and the Rhaphidophoridae are the most basal family of the Ensifera. Therefore, understanding of their mating behaviour may shed light on the evolution of mating behaviour in the Orthoptera as a whole, and contribute to our knowledge on the behavioural ecology of this poorly studied group.