Characteristics and Distribution
The lesser mealworm is very similar in appearance and behaviour to the red flour beetle, Tribolium castaneum. Both beetles are small, between 3 and 6 mm long, and reddish-brown in colour. The main difference is in the shape of their antennae: the antennae of the three-cornered beetle gradually increase in size and have four clubs, while the red flour beetle has only three. Furthermore, red flour beetles can fly short distances, while lesser mealworms cannot.
Ecology and Behaviour
Although lesser mealworms (and red ones) cannot feed on whole, intact grain, they can often be found in large numbers in infected grains, by feeding on broken grain, grain dust and other household foodstuffs such as flour, rice, dried fruit, nuts and beans. Both beetle species can often be found not only in infected grains but also in crevices in pantries and cupboards. The damage caused by these beetles is due to their feeding as well as their dead bodies, excrement and unpleasant secretions. In addition to the unpleasant odour, the presence of beetles promotes the growth of mould.
Summary
The lesser mealworm is an inconspicuous but very harmful storage pest. Its presence in grain warehouses can lead to significant losses in stored crops. It is important to regularly monitor warehouses and take appropriate measures to control it.
Frequently asked questions
What is Tribolium confusum (the confused flour beetle) and why is it considered a storage pest?
Tribolium confusum is a darkling beetle known as a flour beetle that attacks and infests stored flour and grain. It is considered a storage pest because it is common and highly destructive in stored grain and other food products.
How can I tell the confused flour beetle apart from the red flour beetle (Tribolium castaneum)?
They look very similar (small, 3–6 mm, reddish-brown), but their antennae differ: the confused flour beetle’s antennae gradually enlarge and end in four clubs, while the red flour beetle has three. Also, red flour beetles can fly short distances, whereas confused flour beetles cannot.
Where do confused flour beetles typically infest (silos, warehouses, pantries)?
They infest stored products in silos, warehouses, grocery stores and homes. They can also be found in crevices in pantries and cupboards.
What do confused flour beetles feed on if they can’t eat intact grain?
They feed on broken grain, grain dust and other foodstuffs such as flour, rice, dried fruit, nuts and beans. This is why they may still appear in large numbers in grain that is already contaminated or damaged.
What kind of damage do confused flour beetles cause in stored food and grain?
Damage comes from their feeding and from contamination by dead bodies, excrement and unpleasant secretions. Their presence can also promote mould growth and cause an unpleasant odour.
How can I monitor and control confused flour beetles in a grain store or home pantry?
The article recommends regularly monitoring warehouses to detect their presence early. If they are found, appropriate control measures should be taken to reduce losses in stored crops and food products.
