Evidence of temperature‐independent metabolic rates in diurnal N amib D esert tenebrionid beetles

• Published in: Physiological entomology 2014-09, Vol.39 (3), p.254-262
• Main Authors: Lease, Hilary M., Goelst, Kathleen, Seely, Mary K., Mitchell, Duncan
• Format: Article
• Language: English
• ISSN: 0307-6962; 1365-3032
• DOI: 10.1111/phen.12070

To investigate whether the sensitivity to environmental temperature varies between nocturnal and diurnal species of tenebrionid beetle, the metabolic rates of three diurnal species ( Onymacris plana P eringuey, Onymacris rugatipennis H aag and Physadesmia globosa H aag) and three nocturnal species ( Epiphysa arenicola P enrith, Gonopus sp. and Stips sp. ) of beetles from the N amib D esert are measured over a range of temperatures (15–40 °C) that are experienced by these beetles in their natural habitat. The diurnal species O. plana, O. rugatipennis and P. globosa exhibit temperature‐independent metabolic rates (mean Q 10  = 1.2) within temperature ranges that are ecologically relevant for diurnal desert beetles (30–40 °C). Onymacris plana , in particular, has a 20–40 °C rate–temperature slope (0.007 log 10  mL  O 2  h −1  g −1  °C −1 ; Q 10  = 1.1) that is less than half that of the other five beetle species (0.022–0.063 log 10  mL  O 2  h −1  g −1  °C −1 ; Q 10 ranges from 1.3–1.9), suggesting that O. plana is more metabolically independent of temperature than the other nocturnal and diurnal tenebrionids being investigated. Animals with metabolic rates that are decoupled from body temperature (or ambient temperature) may have an ecological advantage that allows them to exploit thermal and spatial niches during extreme temperature conditions.