02927nas a2200337   4500008004100000245016300041210006900204260000800273300001200281490000700293520190100300653002002201653001602221653002702237653002702264653002802291653001702319653000802336653003002344653001202374653002702386653001702413653002202430653000902452653001502461100002102476700001802497700002002515700002002535856003402555       2000                        eng d00aA comparative analysis of metabolic rate in six Scarabaeus species (Coleoptera : Scarabaeidae) from southern Africa: further caveats when inferring adaptation0 acomparative analysis of metabolic rate in six Scarabaeus species  cApr  a553-5620 v463 aAlterations in VO2 or VCO2 are amongst the more polemical physiological adaptations ascribed to insects. Generally, metabolic rate is thought to be lowered in response to arid conditions, and elevated in species from cold environments compared to their more temperate relatives. However, most studies have rarely addressed the influence of both environmental factors in unison. To this end, standard metabolic rate and its temperature dependence were measured (at 4 degrees C intervals from 16 to 32 degrees C) in six Scarabaeus dung beetle species (three flightless, three volant) from a variety of habitats (warm, arid to cool, mesic) in southern Africa using flow-through respirometry. Mass specific VCO2 varied from 0.0158 mi g(-1) h(-1) at 16 degrees C to 0.1839 ml g(-1) h(-1) at 32 degrees C. The slopes of the rate temperature curves were similar for all species (Q(10)s of 2.14-2.84), although the intercepts differed significantly in the direction (warm arid to cool mesic): S. gariepinus<S. hippocrates<S. striatum<S. galenus<S. rusticus<S. westwoodi. General Linear models were fitted to the VCO2 data with treatment temperature, wing status, mean annual rainfall and mean annual temperature as the independent variables. For all six species, the best fit model included treatment temperature and wing status only. Flightless species had significantly lower VCO(2)s than did winged ones. Amongst the flightless species, S. gariepinus, from the driest area, had the lowest VCO2. Among the winged species it was impossible to determine whether environmental temperature or water availability were most important in influencing VCO2; both were significant. We conclude that investigations of metabolic rate modulation, and especially metabolic cold adaptation, in insects must take both temperature and water availability into account. (C) 2000 Elsevier Science Ltd. All rights reserved.10aacclimatisation10aconsumption10acricket gryllus-firmus10adesiccation resistance10adrosophila-melanogaster10agas-exchange10ains10ametabolic cold adaptation10aoxygen-10arespiratory metabolism10arespirometry10aunselected strain10aVCO210awater-loss1 aDavis, A., L. V.1 aChown, S., L.1 aMcGeoch, M., A.1 aScholtz, C., H.  u<Go to ISI>://000085842500019