title: The effects of temperature on the gas exchange cycle in Agathemera crassa.
abstract: Insects exhibit three patterns of gas exchange: continuous (CoGE), cyclic (CGE) and discontinuous (DGE). In this work, we present the first record of a DGE in Phasmatodea and its transition to CGE and to CoGE through a thermal gradient. The rate of CO2 production (VCO2) at 10, 20 and 30°C was examined in adults of Agathemera crassa, a high-Andean phasmid of central Chile. Carbon dioxide release was recorded during 24 h with L:D cycle of 12:12 h in order to record both rest and activity periods. At rest, A. crassa showed three patterns of gas exchange, highlighting the use of DGE preferably at 10°C. As the temperature increased, the CoGE pattern was more frequent being the only pattern observed in all individuals at 30°C. During activity, patterns changed to CoGE with a significant increase in VCO2. Our results support the idea that gas exchange patterns in insects are not distinct but correspond to a continuum of responses addressed by metabolic demand and where DGE can be expressed only under an absolute state of rest. Our results support the idea that the presence of the DGE may be underestimated in other insect taxa because they may have been measured under conditions where this pattern not necessarily can be expressed.
authors.affiliation: Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago, Chile.
authors.forename: Mariana
authors.initials: M
authors.lastname: Thienel
authors.affiliation: Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago, Chile.
authors.forename: Mauricio
authors.initials: M
authors.lastname: Canals
authors.affiliation: Departamento de Ecología and Center of Applied Ecology and Sustainability (CAPES), Facultad de Ciencias Biológicas, Universidad Católica de Chile, Santiago 6513677, Chile.
authors.forename: Francisco
authors.initials: F
authors.lastname: Bozinovic
authors.affiliation: Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago, Chile. Electronic address: clveloso@uchile.cl.
authors.forename: Claudio
authors.initials: C
authors.lastname: Veloso
mesh_terms: D000818:Animals; D002245:Carbon Dioxide / Q000378:metabolism*; D005260:Female; D007313:Insecta / Q000502:physiology*; D008297:Male; D013696:Temperature
chemical_list: D002245:Carbon Dioxide
keywords: Gas exchange patterns; Metabolic demand; Phasmatodea; Temperature