Genus: Eratigena

A few specimens (both adults and larvae) of the arachnophilous stilt bug Metacanthus annulosus Fieber, 1859 were found in a web of the giant house spider Eratigena atrica (C. L. Koch, 1843) in Brno (Czech Republic). This is the first host record, and confirmation of the species’ arachnophily, in Central Europe.

Metacanthus (Cardopostethus) annulosus Fieber, 1859 is a rarely collected species of stilt bug (Hemiptera: Heteroptera: Berytidae), distributed in the Mediterranean region and the Pannonian Basin (Péricart 2001,  Morkel 2007, Vašíček et al. 2018). It is an arachnophilous species living in spider webs, where it feeds on trapped arthropods (Štys et al. 2003, Morkel 2007). So far, these stilt bugs have been found in the funnel-webs of spiders of the genus Agelena (Araneae: Agelenidae). In eastern parts of the Mediterranean area (Anatolia, the Cyclades) the host spider was identified as Agelena orientalis (Štys et al. 2003, Morkel 2007). Agelena orientalis does not occur in Croatia (Nentwig et al. 2018), where M. annulosus was found in the webs of another, still unidentified, species of Agelena s. lat. (Vašíček et al. 2018). In Central Europe, M. annulosus has so far only been collected very rarely, and details of its ecology have been largely unknown (Rabitsch 2004, 2009, Vašíček et al. 2018).