Abstract
he poultry red mite (PRM),Dermanyssus gallinae(de Geer), is a hematophagous mite of economic importance inthe poultry industry. Because PRM lives off-host in habitats potentially shared by many micropredators, bio-control agents have potential to regulate this pest in poultry buildings. The present pilot study was conducted toobtain afirst insight into predatory and parasitic arthropod communities that naturally occur on layer farms inFrance. Species composition and sensitivity to insecticides were determined to estimate the feasibility of con-servation biological control (CBC) of PRM based on a 2-scale concept (regional and local effects). A morpho-molecular approach was used to characterize the taxonomic composition of manure-dwelling arthropod com-munities, with a focus on mesostigmatid mites, that naturally occur in free-range layer farms. Additionally, thesensitivity of some dominant mite species to a common insecticide (deltamethrin) was measured via bioassays.The putative roles of recorded taxa within ecological guilds and their dispersal habits are discussed based on theresults of multivariate and univariate analyses. Local and regional factors had significant effects on both high-level taxonomic arthropod groups and mesostigmatid morphospecies. In addition to documenting the occurrenceand apparent establishment of highly mobile arthropods in hen houses, these results are considered promisingfor the development of CBC against PRM. Populations of two recurrent mesostigmatid morphospecies demon-strated an extreme sensitivity to the pyrethroid, suggesting that even very low levels of insecticide use are likelyto have unnoticed deleterious effects on natural regulation processes in layer buildings. Lastly, a robust methodfor exploring mesostigmatid mite communities in manure is provided.