Biomechanical determinants of bite force dimorphism inCyclommatus metalliferstag beetles

• DOI: 10.1242/jeb.091744
• Publication Date: 2014-03-26T21:35:11Z
• Authors: Jana Goyens; Joris Dirckx; Manuel Dierick; Luc Van Hoorebeke; Peter Aerts
• Keywords: Bite force quotient; Sexual dimorphism; Adult male; Biting

In the stag beetle family (Lucanidae), males have diverged from females by sexual selection. The fight each other for mating opportunities with their enlarged mandibles. It is known that owners of larger fighting apparatuses are favoured to win male–male fights, but it was unclear whether male beetles also need produce high bite forces while grabbing and lifting opponents in fights. We show Cyclommatus metallifer three times as forcefully females. This not entirely unexpected given spectacular nature all more impressive difficulty achieving this long mandibles (long levers). Our results suggest no increase intrinsic muscle strength accomplish this. However, morphological analyses mandibular output levers compensated elongated input (and thus a wider anterior side head). surplus force capability realized enlargement closer muscles mandibles, overall direction remained optimal. To enable forceful bites required ensure reproductive success, head size shape adapted large muscles. Therefore, entire should be regarded an integral part armature.