Mouthpart Ecomorphology and Predatory Behaviour in Selected Rove Beetles of the “Staphylinine Group” (Coleoptera: Staphylinidae: Staphylininae, Paederinae)

Abstract

The representatives of the megadiverse rove beetle subfamilies Paederinae and Staphylininae (Coleoptera: Staphylinidae) are considered generalist predators, although their exact prey-capture behaviour and performance and possible links to mouthpart morphology have rarely been described. Here, we examine these relationships for selected species by SEM analyses of mouthparts and front legs and highspeed videography of prey-capture behaviour. We describe the observed behaviours and structural properties and quantify relationships between prey type, mouthpart morphology, and predatory performance based on morphometric measurements of both the shape and lever properties of the mandible. We show that the Staphylininae considered have morphological and behavioural properties generally associated with generalist predation and that the Paederinae considered display characteristics that are highly specialized on elusive prey such as Collembola. We found correlations between mandible shape and leverage, and body size and prey type. We report distinct prey-capture behaviours: the beetles use front legs and/or mandibles to attack prey, drag prey, or cage it between their legs. These strategies differ among species and situations. Overall, this exploratory study provides insights into the morphology and types of prey capture that must have played a major role in the evolution of these beetles.