Richard graduated from Clemson University with a Master of Agriculture in development and marketing of parasiticides. His areas of expertise include the development of parasiticides for livestock and companion animals.
Darkling beetles are a widespread nuisance in broiler and turkey production. In fact, the darkling beetle is a common pest on broiler farms around the world.¹ They can be found in the litter under feeders and in the walls and insulation of a poultry house. Even in a brand-new poultry house, growers can find darkling beetle infestations by the third flock.
With this level of prevalence, darkling beetle infestations can have a negative economic impact on broiler operations, including the following:
- They can host and transmit diseases from one flock to the next causing decreases in growth and productivity, and increases in mortality, especially during infestations with high beetle populations²
- Birds will be more likely to shy away from the feeders where beetles thrive. This leads to a reduction in feed intake, the potential for slower growth, increased feed conversion rates and feed costs³
- Beetles can cause physical damage to poultry houses leading to costly repairs and increased energy costs⁴
Darkling Beetles Follow Birds
Beetles are attracted to the ammonia in bird droppings and once they infest a house, the beetles will follow the birds.
When a flock comes in, the beetles will first congregate in the litter beneath the feeders. Once that space becomes overcrowded, they will start congregating beneath the litter along the walls before occupying any leftover open space in the poultry house.
Once a flock is moved out of the house, the beetles will move like an army; within 24 hours they will either be in the wall insulation of the house or burrowed down into the dirt floor. Even in turkey brooder houses or hubs where producers are removing the litter and disinfecting the facility between flocks, the beetles are still in the insulation in the walls and will return when the next flock comes in.
Life Cycle of a Darkling Beetle
Darkling beetles lay their eggs in the poultry litter, giving rise to four stages in the lifecycle of a beetle. These darkling beetle larvae then hide to pupate and eventually become adults. The lifecycle of a beetle varies depending on the environment in a poultry house, but with ideal temperature and humidity, the life cycle can be completed in as little as 35 days, or up to 168 days.⁵
How to Monitor Darkling Beetle Infestations
A simple and effective way to monitor darkling beetle infestations is to use the Elanco Beetle Evaluation Form, which is a qualitative assessment tool.
This can be done by selecting six locations in the house to evaluate: two under the feeder lines, two along the wall and two in the middle of the house.
Evaluations are taken by creating a shallow trench several inches wide and observing the number of adults present and the movement of litter. It is best to conduct the initial evaluation just before the flock exits the house when the beetle numbers will be highest and then again 7-days after a new flock arrives.
Look quickly and score beetle quantity as follows:
- None would receive a rating score of 0
- Few present (1–10 beetles), rating score of 1
- Some litter movement (11–50 beetles), rating score of 2
- Moderate movement and the depression fills slowly (51-100 beetles), rating score of 3
- Entire area moving and the depression fills rapidly (101+ beetles), rating score of 4
Add the rating scores of the six locations to determine infestation level:
- Light infestation – score of 0 to 8
- Average infestation – score of 9 to 15
- Heavy infestation – score of 16 to 24
In the next issue of the newsletter we will discuss more about the role of darkling beetles in spreading diseases and how this can impact food safety and animal welfare.
Elanco offers a portfolio of solutions to help control darkling beetles. Contact your Elanco sales team or distributor for more information.
Darkling beetle larvae
Darkling beetle infestations
Darkling beetle insecticides
2Grogan, K., Poultry Times, 2008
3Joseph L. Despins and Richard C. Axtell, Feeding Behavior and growth of Broiler chicks fed larvae of the darkling beetle, alphitobius diaperinus
4Simpson, G., Auburn University the poultry Engineering, Economics & Management newsletter 2007
5Adam, J., Vector Abatement Plan - Darkling Beetles