Differences of the common bed bug and bat bugs

   August 15, 2024  Posted in Articles

Not all bed bugs are alike. In addition to the common bed bug (Cimex lectularius) and the tropical bed bug (Cimex hemipterus, currently rare in the U.S. but occasionally reported in Florida), there are other species that may inhabit or frequent human dwellings, including bat bugs and swallow bugs.

Bat bugs closely resemble bed bugs in appearance but are specifically adapted to feed on bats. There are multiple species of bat bugs in the field, but the most commonly encountered in the U.S. are the Eastern bat bug (Cimex adjunctus) and the Western bat bug (Cimex pilosellus). The Western bat bug (WBB) is the most common bat bug encountered in California. While bat bugs look similar to the common bed bug, several  morphological and behavioral traits can help us differentiate them.

Figure 1: A bed bug vs. a bat bug. Photo: Jim Kalisch – University of Nebraska–Lincoln – Department of Entomology
Figure 2: Distribution of bat bugs in the U.S. (Usinger, 1966). The map shows that the Western bat bug (Cimex adjunctus) was the most common species on the West Coast, while the Eastern bat bug (Cimex adjunctus) was prevalent in the eastern United States at the time of the study.

Differences in appearance (morphology) of bat bugs and bed bugs:

  • Body hairiness: One of the most notable differences between bat bugs and common bed bugs is the overall hairiness of their bodies; bat bugs are generally much hairier than common bed bugs.
  • Hair Length: Another distinguishing feature is hair length. Bat bugs have longer hairs than common bed bugs, with each hair being longer than the width of the eye.
  • Eye Shape: The eyes of the common bed bug protrude more prominently compared to those of bat bugs (Goddard et al., 2012).
  • Pronotum Shape: The plate-like structure on the thorax of bed bugs, known as the pronotum, differs in shape. In common bed bugs, the front edge of the pronotum is deeply concave, while in bat bugs, it is less concave. Please note that tropical bed bugs also have less concavity on the front of their pronotum, but they are less likely compared to bat bugs.
  • Wing Base: In bat bugs, the wing pads have a broader base, meaning the attachment point where they meet is wider.
  • Hind Femur: The hind leg femurs of bat bugs are relatively wider than those of common bed bugs.
Figure 3: Eastern (left) and western (right) bat bugs. Western bat bugs have thicker body hair.

Behavioral differences of bat bugs and bed bugs:

  • Host Preference: Bat bugs prefer feeding on bats, while bed bugs prefer humans. However, both bed bugs and bat bugs may feed on other species if necessary. The common bed bug primarily targets humans but can also feed on bats, chickens, and pigeons.
  • Dispersal: Bed bugs typically reach new locations by hitchhiking on human belongings such as luggage, backpacks, and shoes. In contrast, bat bugs move from nest to nest by traveling with bats.
  • Climbing Ability: The common bed bug is unable to climb glass, whereas the Western bat bug (WBB) can climb glass (Usinger, 1966).

Bat bugs are often found in homes and buildings where bats roost, creating a nuisance for residents. Like bed bugs, bat bugs only attach to their host during feeding (Balvín et al., 2014). However, since bat bugs move between nests by traveling with their hosts, one can speculate that their attachment to the host might extend beyond feeding sessions. In fact, Spencer (1934) observed some WBBs firmly attached to their bat hosts with their mouthparts, while their abdomens extended upwards. This behavior suggests that WBBs can attach themselves to hosts, potentially aiding their hitchhiking from one roost to another. Other studies have shown that bats may carry adult bat bugs on their bodies when trapped outside their roosting sites.

In North America, species in the WBB complex are commonly found on bats. Bat bugs are frequently collected from the following bat species: mouse-eared bats (Myotis sp.), big brown bat (Eptesicus fuscus), canyon bat (Parastrellus hesperus), and pallid bat (Antrozous pallidus) (Usinger, 1966).

References cited

  • Balvín, O., Bartonička, T., Simov, N., Paunović, M., & Vilímová, J. (2014). Distribution and host relations of species of the genus Cimex on bats in Europe. Folia Zoologica, 63(4), 281–289.
  • Goddard, J., Baker, G. T., Ferrari, F. G., & Ferrari, C. (2012). Bed Bugs (Cimex Lectularius) and Bat Bugs (several Cimex Species): A Confusing Issue. Outlooks on Pest Management, 23(3), 125–127. https://doi.org/10.1564/23jun09
  • Spencer, G. J. (1934). The bedbugs of British Columbia. Journal of the Entomological Society of British Columbia, 31, 43–45.
  • Usinger, R. L. (1966). Monograph of cimicidae (Vol. 7). BioOne. https://bioone.org/ebook/download?urlId=10.4182/BQCN5049.1966.i&isFullBook=false
Author: Siavash Taravati