title: Haematophagy is costly: respiratory patterns and metabolism during feeding in Rhodnius prolixus.
abstract: Feeding on the blood of vertebrates is a risky task for haematophagous insects and it can be reasonably assumed that it should also be costly in terms of energetic expenditure. Blood circulates inside vessels and it must be pumped through narrow tubular stylets to be ingested. We analysed the respiratory pattern and the energetic cost of taking a blood meal in Rhodnius prolixus using flow-through and stop-flow respirometry to measure carbon dioxide emission, oxygen consumption and water loss before and during feeding. We observed an increase of up to 17-fold in the metabolic rate during feeding and a change in the respiratory pattern, which switched from a discontinuous cyclic pattern during resting to a continuous pattern when the insects started to feed, remaining in this condition unchanged for several hours. The energetic cost of taking a meal was significantly higher when bugs fed on a living host, compared with feeding on an artificial feeder. No differences were observed between feeding on blood or on saline solution in vitro, revealing that the substrate for feeding (vessels versus membrane) and not the nature of the fluid was responsible for such a difference in the energetic cost. Water loss significantly increased during feeding, but did not vary with feeding method or type of food. The mean respiratory quotient in resting bugs was 0.83, decreasing during feeding to 0.52. These data constitute the first metabolic measures of an insect during blood feeding and provide the first insights into the energetic expenditure associated with haematophagy.
authors.affiliation: Institut de Recherche sur la Biologie de l'Insecte, UMR CNRS 7261 - Université François Rabelais, 37200 Tours, France.
authors.forename: Miguel
authors.initials: M
authors.lastname: Leis
authors.affiliation: Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Minas Gerais, Brazil.
authors.forename: Marcos H
authors.initials: MH
authors.lastname: Pereira
authors.affiliation: Institut de Recherche sur la Biologie de l'Insecte, UMR CNRS 7261 - Université François Rabelais, 37200 Tours, France.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Casas
authors.affiliation: Laboratoire de Biométrie et Biologie Evolutive, UMR CNRS 5558 - Université de Lyon 1, 69622 Villeurbanne, France.
authors.forename: Fédéric
authors.initials: F
authors.lastname: Menu
authors.affiliation: Institut de Recherche sur la Biologie de l'Insecte, UMR CNRS 7261 - Université François Rabelais, 37200 Tours, France claudio.lazzari@univ-tours.fr.
authors.forename: Claudio R
authors.identifier: 0000-0003-3703-0302
authors.initials: CR
authors.lastname: Lazzari
mesh_terms: D000818:Animals; D002245:Carbon Dioxide / Q000378:metabolism; D004734:Energy Metabolism; D005247:Feeding Behavior; D009758:Nymph / Q000502:physiology; D010101:Oxygen Consumption; D012119:Respiration; D012239:Rhodnius / Q000254:growth & development / Q000502:physiology*; D014870:Water Loss, Insensible
chemical_list: D002245:Carbon Dioxide
keywords: Blood-feeding; Chagas; Disease vectors; Metabolic rate; Respiration