Spatial distribution of Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae) in the soil of a poultry house along a breeding cycle

Alphitobius diaperinus (Panzer) is an insect pest of tropical origin introduced in temperate areas. Its spatial distribution in the soil of poultry houses was studied during a winter breeding cycle. Soil sampling was done after the chickens’ removal in three plots (walls, feeders and central area). Three physical parameters were measured: soil moisture, soil density and soil surface compactness. Furthermore, soil and litter temperatures were recorded during the chickens’ breeding period and the following cleaning period. Spatial structure of the insect population in the soil revealed a high heterogeneity: late instar larvae, nymphae and adults were located in the soil (down to 10 cm depth) under the feeders where soil density, surface compactness and moisture content were lower. Management practices greatly influence this spatial structure. Soil constitutes a favourable site for pupation and a refuge (overwintering site) for adults and larvae during stressful periods (decrease of soil temperature during the cleaning period). A. diaperinus reacts to more than one stimulus to locate suitable sites (structural edaphic parameters, hygrotaxis, thermotaxis). The survival of A. diaperinus in temperate area depends on the opportunistic use of suitable warm sites such as the soil layer in poultry houses.