Biology and management of the lesser mealworm, Alphitobius diaperinus (Coleoptera: Tenebrionidae), in broiler production facilities and its reservoir competence for Campylobacter and Salmonella spp

The lesser mealworm, Alphitobius diaperinus (Panzer), is a cosmopolitan pest of poultry production facilities with high economic impacts. Field studies were conducted in broiler production facilities to characterize the beetle population. High numbers of adult beetles were associated with litter moisture of 25–33%, pH of 6.0–8.0 and temperature of 12–21°C. Larval numbers in open areas of the houses were highest when litter moisture was 29–37%, pH was 7.0–9.0 and temperature was 21–24 and 33–36°C, while larval numbers underneath the feeders were highest at a moisture content of 13–21%, pH of 6.5–7.5 and a temperature of 30–39°C. Mean numbers of adult and larval beetles determined from litter samples were much higher underneath the feeders, while the adult population and the majority of larvae sampled had higher estimates in the open areas versus underneath the feeders. Over 77 million beetles were estimated to have occurred in a single house. Beauveria bassiana was applied to broiler houses based on GIS maps showing areas with high beetle numbers and was effective at reducing adult beetle numbers by 85.7% and larval numbers by 97.5%.; The reservoir competence of the lesser mealworm was determined for Salmonella and Campylobacter in broiler facilities. Of 1,113 beetle groups tested for bacteria, 23.9% were Salmonella -positive and 14.9% were positive for Campylobacter. The beetle may be important in the horizontal spread of these bacteria among broilers, and can additionally act as a Salmonella reservoir by carrying infection from one flock growing period to the next. A series of laboratory experiments was designed to test the vector and reservoir competence of the lesser mealworm for Campylobacter jejuni. C. jejuni was detected on the exterior of beetles for 12 h, from the interior of the beetles for 72 h, and from the feces of the beetles for 12 h after exposure. Ninety percent of the birds that consumed a single adult or larval beetle became Campylobacter-positive, while 100% of the birds that consumed 10 adults or larvae became positive.