title: Transitions in insect respiratory patterns are controlled by changes in metabolic rate.
abstract: We examined the respiratory patterns of Rhodnius prolixus and Gromphadorhina portentosa as metabolic rates varied with temperature to determine whether insects transition from discontinuous (DGC), cyclical and continuous respiration as a response to increasing aerobic demand. Using flow through respirometry we: (1) determined the effects of temperature on metabolic rate; (2) objectively defined periods of spiracular closure; (3) observed whether there was a correlation between metabolic rate and length of spiracular closure. At low temperatures both species exhibit lengthy periods of spiracular closure reflecting a discontinuous respiratory pattern. As metabolic rate increased, periods of spiracular closure decreased and insects displayed a more cyclical pattern of respiration. As metabolic rates increased even further under the highest experimental temperatures, periods of spiracular closure decreased even more and a continuous respiratory pattern was employed by both species. Our results suggest that the three described respiratory patterns in insects are not distinct but are instead a continuum of respiratory responses driven by the metabolic demand experienced by the insect.
authors.affiliation: University of California, Irvine, Ecology and Evolutionary Biology Department, 321 Steinhaus Hall, Irvine, CA 92697-2525, United States. hcontrer@uci.edu
authors.forename: H L
authors.initials: HL
authors.lastname: Contreras
authors.forename: T J
authors.initials: TJ
authors.lastname: Bradley
mesh_terms: D000825:Animal Structures / Q000502:physiology; D000818:Animals; D002245:Carbon Dioxide / Q000378:metabolism; D003058:Cockroaches / Q000502:physiology*; D004734:Energy Metabolism / Q000502:physiology*; D012143:Respiratory Physiological Phenomena; D012239:Rhodnius / Q000502:physiology*
chemical_list: D002245:Carbon Dioxide