Comparative larval ultramorphology of some myrmecophilous Aleocharinae (Coleoptera, Staphylinidae), with a first description of the larvae of Amidobia talpa (Heer O, 1841) and Oxypoda haemorrhoa (Mannerheim C.G., 1830), associated with the Formica rufa species group

Abstract

The paper describes the external structures of the late larval stages of two Palearctic myrmecophilous staphylinids: Amidobia talpa and Oxypoda haemorrhoa associated with the Formica rufa species group. This is the first-ever description of the larva of Amidobia, and the only complete, detailed account of the morphology of this developmental stage in the genus Oxypoda currently available. For the first time in these two genera, 13 and 10 larval diagnostic features, respectively, are proposed. Morphological differences have been established between known and the newly described larvae of five species (genera) of myrmecophilous and one non-myrmecophilous Aleocharinae, belonging to three tribes. Amidobia talpa and O. haemorrhoa are probably typical, tiny predators, like most other Aleocharinae, including non-myrmecophilous ones. Being very small and highly mobile, they are ignored by worker ants. Not surprisingly, no particular larval morphological modifications were found to enable them to survive among ants. Such features have, however, evolved in the larvae of larger aleocharines, that is, those that are perceived by ants and are wholly integrated with their hosts in the ant nest (e.g. Lomechusa). This comparative analysis of the functional morphology of the larvae of known myrmecophilous Aleocharinae is a springboard to further such studies of these interesting insects.