Effects of experimental modification of temperature and humidity on abundance of dermestid beetles in nests of blue tits

Abstract

Many factors may affect the diversity and abundance of arthropods in their natural habitats including changes in temperature and humidity. Sometimes, large arthropods remain undetected in unsuspected habitats such as bird nests. Here, we explore the effects of an experiment modifying temperature and relative humidity inside the nest of a troglodyte bird species, the blue tit, Cyanistes caeruleus (L.) (Passeriformes: Paridae), on the abundance of dermestid beetles (Coleoptera: Dermestidae) inhabiting the nests. Ten taxa were identified, six at the species level and four—based on larval stages—at the genus level. Most of the dermestids found in the larval stage were nidicolous dermestids of the genus Anthrenus. Specimens of necrobiont dermestids (those that feed on carcasses in both the larval and adult stages) were found in lower numbers, and almost always in adult stages. The abundance of dermestid larvae found in blue tit nests where the temperature or the humidity were experimentally increased was significantly higher than in the control nests. In addition, adult necrobiont dermestids of genus Dermestes appeared more frequently in those nests where corpses of blue tit nestlings were found.