More urban species: Red flour beetle

[urbpan]

A coworker called me over to identify some insects lurking in a mealworm colony. They were so small (about 2 mm long each) I couldn't even tell what they were at first--I actually thought they were fruit fly pupae.

I took this picture and could see that they were beetles. Not sawtooth grain beetles, because these lack the distinctive teeth on the thorax. I went to my pest control text, since it seemed likely that they were known grain pests.

It soon became clear that these were flour beetles (Tribolium sp.). There are two common types, T. castaneum the red flour beetle--so called because of the reddish brown color--and T. confusum the "confused" flour beetle, which gets its name because it's easily confused with the other. Really. The "confused" is more tolerant of cold temperatures, and is more common in northern climates. However, the red has another field marking that helps remove the confusion: it flies, while the other does not. I was told these beetles had been observed flying, allowing me to identify them to species.

I was also interested to learn that both kinds of flour beetles are in the family Tenebrionidae: the darkling beetles. Darkling beetles are what I call the adult form of mealworms. So the mealworm colony was infested with their own tiny cousins. Hard to consider them contaminants, more like freeloaders.

Comments

[elainetyger.livejournal.com]

Those so-called grain pests eat a lot more than grain. We even found them once in a carton of dried chili peppers.

[ssorca19.livejournal.com]

Once had these guys get into and destroy a whole 30lb bag of rat lab blocks...