Bread or biscuit beetle.
Found across Australia and worldwide
Larvae are a white “curl grub” up to 3.5 mm long. They can move quite rapidly.
Adults are a reddish brown, oval beetle, 2.0-3.5 mm long, with distinctive 3-clubbed antennae.
Can be confused with the cigarette beetle, but the antennae on the cigarette beetle have a uniform serrated appearance. Also, the elytra (wing covers) of the cigarette beetle have a smooth appearance whereas the drugstore beetle has a lined appearance with rows of pits running the length of the wing covers.
Female beetles can lay up to 100 eggs in her lifetime.
The life-cycle can be completed in as little as 2 months, but more typically the larval period lasts 4-5 months, with 2-3 weeks in the pupal stage.
Adults beetles live between 2-4 weeks.
Only the larvae causes the damage through feeding.
Drugstore larvae will eat a wide range of dry packaged plant based foods, as well as on prescription drugs which gave rise to its name. They will also feed on wool, hair, leather and books. They will feed on rodent baits.
Drugstore details tend to be more of a pest of processed and packaged foods rather than stored grain facilities.
Drugstore beetles have a symbiotic relationship with yeasts that produce vitamin B. The vitamin B is deposited on eggs before laying and ingested by the hatching larvae when they eat the egg material. This allows the larvae to feed and survive of low nutritional food items.