Triatominae or Kissing Bugs in California
The assassin bug subfamily Triatominae, or kissing bugs, comprises about 140 valid species (Galvão et al., 2003), many of which are vectors of Trypanosoma cruzi (Chagas, 1909), the causative agent of Chagas disease or American Trypanosomiasis that effects about 12 million people in Middle and South America (Beard et al. 2003). Twelve species of Triatominae in the genera Paratriatoma Berber and Triatoma Laporte occur in the United States (Henry and Froeschner 1988). They live mostly in nests of wood rats in the genus Neotoma Say and Ord, but are attracted to light and therefore human habitations at night. Transmission of Trypanosoma cruzi to pets and humans has been documented in several instances in the United States (Beard et al. 2003, Dorn et al. 2007), including one case of indigenous Chagas disease from California (Schiffler et al. 1984). In addition, bites of Triatominae in the southwestern United States are perceived as a problem due to the hypersensitive reactions of about 7% of humans (Ryckman 1985, Marshall et al. 1986, Klotz et al. 2006). Due to the fact that human settlements are continuously expanding into the natural habitat of these insects, Triatominae have the potential to become a more common health problem in California.
We have started to monitor the distributions of species of Triatoma and Paratriatoma in Southern California, using light traps. During the season of 2007 (June-August), we exclusively collected specimens of Triatoma protracta and Paratriatoma hirsuta. At most localities, only single specimens of T. protacta were found, but entomologist Chris Conlan, who is running a light trap at his house in San Diego Co. supplied us with hundreds of specimens collected over a 2 month period of time.
Apart from getting a recent perspective on the distribution of T. protracta and related species, our lab is interested in the phylogeography of T. protracta using the biogeographic hypothesis proposed by Ryckman (1967) as our null hypothesis.
We are also investigating the relationship of the monotypic genus Paratriatoma within Triatominae using molecular data. The question of Paratriatoma affinities was raised almost 30 years ago by Lent & Wygodzinsky (1979). These authors suggested that P. hirsuta may either be closely related to the protracta group or have a basal position within Triatomini. The position of Paratriatoma in a phylogeny may have implications on our understanding of host evolution within the group, but also provide insights into the evolution of camouflaging behavior in Triatominae.