Darkling beetle species were the most abundant type of insect recorded in a study exploring potential vectors of Histomonas meleagridis, the protozoan pathogen which causes the common broiler breeder disease histomoniasis.
Over the course of a year, researchers at Auburn University used trapping techniques to record insects inside and outside poultry houses on four farms.
During the work, presented at the International Poultry Scientific Forum1, they trapped a total of 5,199 insects, with Diptera (flies) the most common insect order recorded. Traps kept outside the houses trapped significantly more specimens and had greater species diversity.
During the second collection of specimens, there was an outbreak of histomoniasis, also known as blackhead disease, on one of the farms. Four months after this outbreak, PCR testing revealed that 50% of darkling beetles harbored Histomonas DNA. They also sporadically detected the DNA of Heterakis gallinarum, a cecal worm that is known to be a reservoir of H. meleagridis, on beetles on all the farms.
Despite this, the fact that 99% of the beetles in the study were found inside poultry houses suggests that they are unlikely to be carrying diseases from house to house or farm to farm, the researchers suggested.
170 other insects were selected for DNA analysis. Four proved positive for H. meleagridis and one for H. gallinarum, suggesting a need for further exploration of their role as potential vectors of disease.
1 Ruediger, H, et al. Description of insect populations in and around broiler breeder pullet farms with regard to potential vectors of Histomonas meleagridis. International Poultry Scientific Forum, 2023, Atlanta, USA.