Triatomines are generally secretive, hiding in cracks and crevices. Most species are nocturnal and actively seek blood from diurnal hosts that are resting and sleeping at night. Kissing bugs can survive for months without a blood meal. When hosts are available, they commonly feed every 4-9 days. As in other hematophagous arthropods, feeding behaviour is initiated by a combination of physical and chemical factors. The amount of blood ingested depends on the duration of feeding, which again is governed by the presence of chemicals in the blood of the host and by stretch receptors in the abdomen of the bug. The time required to engorge fully varies from 3 to 30 min. After engorging, the bug removes the rostrum from the host and, in most species, defecates on or near the host before crawling away to seek shelter.
As Trypanosoma cruzi is excreted by the bug during defecation, the interval between feeding and defecation is a major factor in determining the effectiveness of a species as vector of T. cruzi. The pathogen enters the host either via normal healthy mucosa or broken skin. Pruritic skin reactions following triatomine bites tend to enhance transmission of T. cruzi by stimulating the bitten host to scratch infective faeces into the bite wound.