(4) The rust-red flour beetle and the confused flour beetle

Difference between the rust-red flour beetle and the confused flour beetle

Fig. 2. 1. The rust-red flour beetle (left) is often mistaken for the confused flour beetle (right). The main difference between the look of the two species is the abrupt transition between the third and fourth antenna links of the rust-red flour beetle. The confused flour beetle has a smooth transition between the antenna links. The biology of the two species exhibits only small differences, but the differences are still significant enough to determine that one of the two species is successful while the other performs poorly in our climate.

According to British statistics, the rust-red flour beetle is that kind of food pest that most frequently is brought to Europe by sea. It has been found in 23% of the consignments while the closely related confused flour beetle has only been seen in less than 1% of the consignments.

In the Nordic countries the frequency is just the opposite. The rust-red flour beetle is a tropical species with slightly higher heat requirements than the confused flour beetle and it belongs in a warm, temperate climate. In addition, the rust-red flour beetle is not as tolerant to cold as the confused flour beetle.