Yellow Meal Worms are considered only to be scavenger insects because they are commonly known to infest stored food products. This is not entirely true, although they do infest food products they also serve a beneficial purpose to fishermen, who breed them for fishing bait.

Yellow Meal Worms are the larval form of darkling beetles. They are worm-like and somewhat hardened for burrowing. The egg is white. The pupa is 1/2 to 3/4" long, white initially then darkening just before the beetle emerges. The larval stage may molt 9-20 times. Mealworms live in areas surrounded by what they eat under rocks, and logs, in animal burrows and in stored grains. They clean up after plants and animals, and therefore can be found anywhere where "leftovers" occur.