Arthropod communities of laying hen houses: An integrative pilot study toward conservation biocontrol of the poultry red mite Dermanyssus gallinae

- Multidisciplinary community- and species-level investigation toward a new biocontrol area.
- A robust method for exploring mesostigmatid mite communities in manure is provided.
- The poultry-farm's arthropodofauna encompasses interesting predatory species.
- Extreme sensitivity to pyrethroid raises the question of unintended effects of treatments.
- Effects of region- and local scale factors make conservation biocontrol in poultry farms promising.

The poultry red mite (PRM), Dermanyssus gallinae (de Geer), is a hematophagous mite of economic importance in the poultry industry. Because PRM lives off-host in habitats potentially shared by many micropredators, biocontrol agents have potential to regulate this pest in poultry buildings. The present pilot study was conducted to obtain a first insight into predatory and parasitic arthropod communities that naturally occur on layer farms in France. Species composition and sensitivity to insecticides were determined to estimate the feasibility of conservation 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 communities, with a focus on mesostigmatid mites, that naturally occur in free-range layer farms. Additionally, the sensitivity 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 the results 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 occurrence and apparent establishment of highly mobile arthropods in hen houses, these results are considered promising for the development of CBC against PRM. Populations of two recurrent mesostigmatid morphospecies demonstrated an extreme sensitivity to the pyrethroid, suggesting that even very low levels of insecticide use are likely to have unnoticed deleterious effects on natural regulation processes in layer buildings. Lastly, a robust method for exploring mesostigmatid mite communities in manure is provided.