European Journal of Entomology

      ISSN 1210-5759 (print), 1802-8829 (online)

Eur. J. Entomol. 2010, 107(2): 271–275  

Enhanced tolerance to water stress in adults of the South India strain of the seed beetle, Callosobruchus maculatus (Coleoptera: Bruchidae), as a product of large body size

YODER J.A.*, CHRISTENSEN B.S. & KEENEY G.D.

A water balance study was conducted on newly-emerged adults of seed beetle, Callosobruchus maculatus, to explore how South India strain survives longer than Brazil strain in laboratory cultures. No difference between strains was noted with regard to dehydration tolerance, and water conservation features confirm classification of this species as xerophilic. There was no evidence for critical transition temperature (CTT), thereby safeguarding against excessive water loss as the temperature rises, or for critical equilibrium humidity (CEH), indicating that water is imbibed as a liquid. In contrast to the Brazil strain, adults of the South India strain were distinguished by a larger body size, resulting in a lower net transpiration rate with suppressed activation energy (Ea, permeability constant) for water loss, and a lower percentage body water content due to a higher dry mass (fat). These modifications for water balance of the South India strain link enhancing time for reproduction and distribution spread in the adult with the higher seed consumption/respiratory rate trait that has been previously reported for larvae of this strain.

Address
Department of Biology, Wittenberg University, Springfield, OH 45501, USA; e-mail: jyoder@wittenberg.edu

Keywords
Water balance, net transpiration rate, activation energy, Callosobruchus

accepted: Jan 19th, 2010    published: Apr 15th, 2010    URL: http://www.eje.cz/scripts/viewabstract.php?abstract=1535


© 2003 Institute of Entomology

 Webdesign by Scisoft