Red Flour Beetle and Confused Flour Beetle

Category: OLI
Minimum Life Cycle: 23 days.
Distribution: Worldwide; on many products, secondary on whole grain; red flour beetle more common in tropics than confused flour beetle.
Biology:
Eggs - Up to 450 eggs per female laid on foodstuffs over several months.
Larvae - Prefer cereal embryos.
Adults - Can live for 18 months; many strains of red flour beetle resistant to malathion.

Red Flour Beetle and Confused Flour Beetle (Tribolium castaneum and T. confusum). The red and confused flour beetles are cosmopolitan pests of a wide range of grain, cereal, and other food products, but they prefer milled grain. The antennae of the confused flour beetle gradually expands toward the end, while that of the red flour beetle abruptly expands at the end to form a club of three segments. The red flour beetle will fly under certain conditions; however, the confused flour beetle does not fly. The adults are very active, especially in the evening hours. These insects produce a foul odor and taste in the food products that they infest, which are caused by pheromones and toxic quinone compounds (Figure 15).

(Slide and top caption courtesy of ICI Americas, Inc.)

illustration of a red and confused flour beetle

Figure 15. Red flour beetle and confused flour beetle.