Feeding

Depending on the type of habitat occupied by the different triatomine species (sylvatic, peridomestic, domestic) wild or domestic animals as well as humans are frequented for blood feeding.

Both sexes of adults and all nymphal instars require blood for their survival and development.

As in other hematophagous arthropods, feeding behaviour is initiated by a combination of physical and chemical factors. In this context heat and carbon dioxide have been mentioned. Furthermore, a pheromone in the faeces of nymphal and adult Triatoma infestans and in nymphal Rhodnius prolixus has been reported to attract unfed nymphs. For more detailed information see Krinsky (2019).

Activity Dynamics

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. In some cases, bugs will feed in daylight, typically on hosts that are nocturnal. Kissing bugs can survive for months without a blood meal. When hosts are available, triatomines commonly feed every 4-9 days.

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. Adult bugs may imbibe blood equivalent to about three times their body weight, while nymphs may imbibe 6-12 times their unfed weight. 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. For more detailed information see Krinsky (2019).

As Trypanosoma cruzi, the pathogenic agent of Chagas disease, 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.

Host Spectrum

Depending on the type of habitat (sylvatic, peridomestic, domestic) wild or domestic animals as well as humans are frequented by triatomines for blood feeding. Amphibians, lizards, opossums, rodents, armadillos, sloths and bats are some of the wild animals used as food source. The peridomestic species use domestic animals as hosts according to their hiding places in chicken coops, other bird enclosures, stables, corrals and rabbit and guinea pig houses. The domestic triatomine species are almost exclusively associated with humans and their pets. Many of the so-called peridomestic triatomine species, as well as a few domestic ones, have maintained sylvatic adaptations and may migrate from wild hosts to domestic animals and humans, depending on the availability of suitable habitats and hosts (Krinsky, 2019).

Individual triatomine species show definite host preferences and may favour bats, birds, armadillos, wood rats, or humans.

Triatomines transmit the pathogenic agent of Chagas disease, Trypanosoma cruzi, to a variety of domestic and wild animals. Some 150 mammal species are susceptible to T. cruzi, with possible high prevalences in dogs, cats, rodents, and both domestic and wild lagomorphs, constituting an important reservoir for human infection.

Epimastigotes of Trypanosoma cruzi, light microscopical image (by courtesy of P. Bourdeau, ONIRIS, Nantes, France)
Epimastigotes of Trypanosoma cruzi, light microscopical image (by courtesy of P. Bourdeau, ONIRIS, Nantes, France)

References

Introduction

Krinsky WL: Chapter 8: True Bugs (Hemiptera). In: Mullen GR, Durden LA (eds.): Medical and Veterinary Entomology. 3rd edn., 2019, Academic Press, Elsevier Inc., London, pp. 107-27

Activity Dynamics

Krinsky WL: Chapter 8: True Bugs (Hemiptera). In: Mullen GR, Durden LA (eds.): Medical and Veterinary Entomology. 3rd edn., 2019, Academic Press, Elsevier Inc., London, pp. 107-27

Host Spectrum

Krinsky WL: Chapter 8: True Bugs (Hemiptera). In: Mullen GR, Durden LA (eds.): Medical and Veterinary Entomology. 3rd edn., 2019, Academic Press, Elsevier Inc., London, pp. 107-27

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