Which bug is often confused with the common bed bug but does not infest homes in large numbers?

The bat bug is often mistaken for the common bed bug due to their physical similarities, particularly in size and body shape. Both bugs belong to the same family, Cimicidae, which contributes to the confusion. However, bat bugs do not typically infest homes in large numbers like bed bugs do. They are primarily associated with bat colonies, where they feed on the blood of bats. In contrast, common bed bugs thrive in human environments, favoring areas where people sleep, and they can quickly establish large populations, making them notorious for infestations.

The other options—sticktight fleas and grain mites—are distinct from bed bugs and do not share the same characteristics. Sticktight fleas are parasites that infest pets and not commonly associated with human habitation in the same way, while grain mites are associated with stored grains and do not appear similar to bed bugs. The key aspect to remember is that bat bugs, while related to bed bugs and visually similar, are not a threat to homes in large numbers, setting them apart from the common bed bug.