Table of Contents
International Journal of Evolutionary Biology
Volume 2013 (2013), Article ID 576452, 12 pages
http://dx.doi.org/10.1155/2013/576452
Research Article

Drosophila melanogaster Selection for Survival after Infection with Bacillus cereus Spores: Evolutionary Genetic and Phenotypic Investigations of Respiration and Movement

1Department of Food Science and Technology, University of Nebraska-Lincoln, Lincoln, NE 68583, USA
2Department of Statistics, University of Nebrasksa-Lincoln, Lincoln, NE 68583, USA
3Department of Biology, Indiana University, Bloomington, IN, USA
4School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE 68588, USA

Received 29 June 2012; Revised 3 October 2012; Accepted 23 November 2012

Academic Editor: Rob Kulathinal

Copyright © 2013 Junjie Ma et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Laboratory populations of D. melanogaster have been subjected to selection for survival after live spores of B. cereus were introduced as a pathogenic agent. The present study was designed to investigate correlated traits: respiration as a metabolic trait and movement as a behavioral trait. An underlying hypothesis was that the evolution of increased survival after B. cereus infection exerts a metabolic cost associated with elevated immunity and this would be detected by increased respiration rates. There was support for this hypothesis in the male response to selection, but not for selected-line females. Two phenotypic effects were also observed in the study. Females especially showed a marked increase in respiration after mating compared to the other assay stages regardless of whether respiration was measured per fly or adjusted by lean mass or dry weight. Given that mating stimulates egg production, it is feasible that elevated metabolism was needed to provision oocytes with yolk. Females also moved less than males, perhaps due to behaviors related to oviposition whereas elevated male activity might be due to behaviors associated with seeking females and courtship. Relatively low movement of females indicated that their elevated respiration after mating was not due to a change in locomotion.