Patterns of respiration in Locusta migratoria nymphs when feeding


Professor S. J. Simpson, Department of Zoology and University Museum of Natural History, University of Oxford, South Parks Road, Oxford, OX1 3PS, U.K. Tel: +44 (0)1865 272976; fax: +44 (0)1865 272970; e-mail:
 1Present address: Department of Physiology, Biosciences Institute, University of São Paulo, 05508-900 São Paulo, SP, Brazil.


Flow-through respirometry was used to investigate patterns of respiration of fifth-instar Locusta migratoria L. nymphs fed a chemically defined, synthetic food. Each animal was recorded for up to 2.7 h, during which they had access to food and water ad libitum, and at least one meal was taken. The start of feeding was coincident with a sudden and rapid rise in respiration. Both carbon dioxide (CO2) production and oxygen (O2) consumption rose, the traces for the two gasses showing a high degree of alignment. The end of a meal correlated with a sudden and rapid decrease in respiratory rate towards resting levels. When feeding was interrupted by an intra-meal pause, respiratory rate tended to drop marginally and then stabilize, before rising rapidly upon the resumption of feeding within the meal. Maximal rates of respiration during feeding represented a 3–4-fold increase over those at rest. Walking and climbing within the chamber were not associated with any noticeable change in respiratory rate above baseline. When locusts were quiescent between feeding episodes, respiration was steady and continuous, rather than discontinuous. Possible causes for large changes in respiration during feeding are discussed.