In areas where Chagas disease occurs (from the southern United States to northern Argentina), all triatomine species are potential vectors of the Chagas disease parasite Trypanosoma cruzi, but only those species that are well adapted to living with humans (such as Triatoma infestans and Rhodnius prolixus) are considered important vectors.

[4][5] At the beginning of the 19th century, Charles Darwin made one of the first reports of the existence of triatomines in America in his Journal and Remarks, published in 1839 and commonly known as The Voyage of the Beagle.

The following is an extract which he based on his journal entry dated 26 March 1835:[6]: 315 We crossed the Luxan, which is a river of considerable size, though its course towards the sea-coast is very imperfectly known.

We slept in the village, which is a small place surrounded by gardens, and forms the most southern part, that is cultivated, of the province of Mendoza; it is five leagues south of the capital.

At night I experienced an attack (for it deserves no less a name) of the Benchuca (a species of Reduvius) the great black bug of the Pampas.

It was curious to watch its body during the act of sucking, as it changed in less than ten minutes, from being as flat as a wafer to a globular form.

[6]: 315 Note: Luxan is a reference to the town/district of Luján de Cuyo, though there is no longer a river named after the town in its vicinity (the only Luján River in present-day Argentina empties into the Río de la Plata and is basically a minor branch of the Rio Paraná); the Benchuca is identified by Richard Keynes as Triatoma infestans which is commonly called the "Vinchuca" bug.

[6] Considerable medical speculation has occurred as to whether or not Darwin's contact with triatomines in Argentina was related to his later bouts of long-term illness, though it is unlikely to have been caused on this specific occasion, as he made no mention of the fever that usually follows the first infection.

[7] In 1909, Brazilian doctor Carlos Chagas discovered that these insects were responsible for the transmission of T. cruzi to many of his patients in Lassance, a village located on the banks of the São Francisco River in Minas Gerais (Brazil).

Carbon dioxide emanating from breath, as well as ammonia, short-chain amines, and carboxylic acids from skin, hair, and exocrine glands from vertebrate animals, are among the volatiles that attract triatomines.

Triatomines characteristically leave two kinds of feces like strikes on walls of infected houses; one is white with uric acid, and the other is dark (black) containing heme.