Kissing bugs are large, dark brown or black true bugs belonging to the insect Order Hemiptera. Some species have patterns and markings on their abdomen, which vary by species. As adults, they range in size from 0.5 to over 1 inch (13.0 to 33.0 mm) in length. Kissing bugs get their name because these insects often bite people while sleeping and often bite around the mouth or on the face. They are also triatomine bugs, conenose bugs, and Hualapai (or Wallapai) tigers. Although kissing bugs are in the same insect order as bed bugs, and both feed on blood, they have different life histories. There are 11 kissing bugs in the U.S., and seven species in the genera Triatoma and Paratriatoma are found in Arizona. The most troublesome and numerous species associated with human dwellings in Arizona are T. rubida, T. protracta and T. recurva.
Kissing bugs are often associated with the nests of Neotoma woodrat species (also called packrats) and other wildlife. However, they can also be related to domesticated animals and are often found in the bedding of outdoor doghouses and chicken coops. Adults fly well and are attracted to lights after dark. In suburban and rural Arizona, kissing bugs are often attracted to porch lights. At dawn, they may seek a way to avoid sunlight and heat and enter a residence through a doorway gap or cracks around window screens. They also enter homes by moving up from crawlspaces beneath flooring or hitchhiking on pets. Once inside, they move toward areas of low light intensity, hiding in and under furniture (between mattresses is a favorite hiding place) and in closets during the daytime hours. Adult kissing bugs are most encountered during their dispersal season, May through July when they fly toward homes attracted by lighting. Some species actively seek out humans and domestic animals to feed on. They are attracted to the gases we exhale, skin odors, and the warmth of our bodies. Feeding occurs mainly at night, after which they tend to move away from the host. Engorged bugs are often found amongst bedding and drapes close to the bed in the morning. The kissing bug life cycle begins with the spring to summer nighttime dispersal flight of adults from rodent burrows and dens. Eggs are laid in rodent nests in summer or early fall, hatching in three to five weeks.
Nymphs pass through five immature stages before becoming mature adults, and each stage requires a full blood meal to develop to the next stage. Kissing bugs rapidly suck blood within 10 to 30 minutes. Fully engorged bugs can take one to five times their weight in blood, and the bugs will feed about every one to two weeks when hosts are available and temperatures are warm. Adults live into mid- to late autumn. Kissing bugs overwinter as developing nymphs and molt into adults in spring. Females can lay up to several hundred eggs over their lifespan, depending upon conditions. Active dispersal is achieved by flight in adults, usually around dusk and early evening. Immature kissing bugs cannot fly but crawl to find a blood source.
In southern and central South America, kissing bugs are the primary vectors of the parasite Trypanosoma cruzi that causes Chagas disease. Chagas is a severe, often chronic, and sometimes lethal disease. Unlike mosquito and tick vector pathogens, the kissing bug bite does not transmit the parasite. The T. cruzi protozoan is transmitted in the kissing bug feces, which may be scratched into the bite wound, ingested, or accidentally rubbed by the host into moist tissues around the eyes, nose, and mouth. Chagas disease is low in the U.S., even though many species of kissing bugs carry T. cruzi in their gut. Researchers attribute the low incidence of Chagas disease in the continental U.S. to the low efficacy of protozoan transmission by the bugs, infrequent human contact, and the poor ability of the bugs to permanently colonize homes. Studies have shown that over 40% of the kissing bugs around Tucson, Arizona carry the parasite, but it is scarce for these bugs to transmit the disease to people. Evidence of Arizona residents acquiring T. cruzi from Arizona kissing bugs (called autochthonous transmission) is rare. Transmission of T. cruzi within the continental U.S. is rare, with 28 autochthonous infections documented from 1955 to 2015. However, the overall risk in the U.S. is undefined, and reporting suspected cases will aid surveillance efforts. Chagas cases have been increasing in the U.S., Canada, and some European and Western Pacific countries. This could be due in part to increased population mobility between Latin America where the disease is endemic, and the rest of the world.
Reference
Li SL, Gouge DH, Ruberto I, Nair S, Fournier AJ, Hall WE. 2022. What You Should Know About Kissing Bugs. The University of Arizona Cooperative Extension, az1992.
