Comparative morphology of the larval stages of Cholevinae (Coleoptera: Leiodidae), with special reference to those in the Netherlands

Among insects, the description of the morphology of immature life stages is often less extensive than that of adults. This is also the case with the subfamily Cholevinae (Coleoptera: Leiodidae). Of the 39 species of Cholevinae known to occur in the Netherlands, only the larvae of 15 species are described in the literature, often insufficiently. To develop new descriptions and identification keys for the larvae, specimens from Germany and the Netherlands, mainly collected by Peter Zwick and Menno Schilthuizen respectively, were examined. In addition, an extensive inventory of the literature was carried out. From this, keys were constructed and descriptions were made covering all three larval stages of all four tribes occurring in the Netherlands, consisting of 28 Dutch species as well as five other species. For distinction of tribes, mandible shape and the relative length of urogomphomere I were primarily used, whereas for distinction of species, chaetotaxy of the mandible, maxilla, antenna, tergite, and urogomphus was primarily used. More specimens should be collected to confirm the characteristics used in the keys and the descriptions, as the existing specimens may not represent the full range of intraspecific variation, some specimens may be worn down, and some specimens appear to have been misidentified. Although the keys are currently not usable for the full identification to species, they do provide a scaffold for the further development of a key to the species of Northwestern Europe. Additionally, the morphological characteristics used in the keys may be related to the diets of the larvae and be used to further investigate the phylogeny of the group, such as the paraphyly of Catops Paykull, 1798 and the delineation of the Catops fuscus -group.