Habitat characteristics of Aradidae (Insecta: Heteroptera) in two french deciduous forests

Forest management can have a strong negative effect on biodiversity, especially for saproxylic species. To protect this biodiversity, we must understand the specific requirements of the concerned species. However, information on mycetophagous Aradidae in temperate forests is scarce, and the factors influencing their abundance are poorly known. We studied the habitat requirements of the Aradidae (Heteroptera) Aneurus avenius and Aneurus laevis in two french deciduous forests. We first defined their habitat preferences at the piece-of-wood scale; we compared the effects of tree species, degree of decay, bark dehiscence and surface area. At a larger (stand) scale, we tested the effects of surface area and volume of standing or fallen dead wood, and the presence of fungi. Three other species, i.e. Aradus brenskei, A. conspicuus and A. versicolor were encountered during our study, but their occurrences were too rare to perform statistical tests, so only descriptive data are given for these species. We concluded that the two Aneurus species have slightly different habitat requirements, with A. avenius being more abundant on oak and under dehiscent bark, and favoured in stands with small branches and the presence of fungi, while A. laevis is more abundant on decayed wood and under various types of bark in stands with small branches. All species of Aradidae vary in their habitat preferences, and can be sensitive to different types of exploitation. Some species need large senescent trees, while others, like the Aneurus species, depend on small fresh deadwood and are therefore more sensitive to woodfuel harvesting.