Effect of temperature on Wolbachia density and impact on cytoplasmic incompatibility.
The outcome and the evolution of host-symbiont associations depend on environmental constraints, but responses are difficult to predict since they arise from a complex interaction between the host, the parasite and the environment. The situation can be even more complex when multiple parasite genotypes, with potentially different responses to environmental changes, coexist within a single host. In this paper, we investigated the effect of the temperature (from 14 to 26 degrees C) during the host development on the density of 3 strains of the intracellular bacterium Wolbachia that coexist within the wasp Leptopilina heterotoma. In this species, Wolbachia induces cytoplasmic incompatibility, a sperm-egg incompatibility that allows it to spread and persist in host populations. Using real-time quantitative PCR we found that (i) Wolbachia density is temperature-specific and highest at 26 degrees C; (ii) the order of the abundance of the 3 Wolbachia strains does not vary with temperature changes; (iii) the response of bacterial density to temperature occurs within a single insect generation, during the egg-to-adult developmental period; (iv) in this species, temperature-related changes in Wolbachia density do not influence cytoplasmic incompatibility.
Mouton
L
L
Laboratoire de Biométrie et Biologie Evolutive, UMR CNRS 5558, Université Lyon 1, 43 Bd du 11 Novembre 1918, 69622 Villeurbanne Cedex, France. laurence.mouton@unibas.ch
Henri
H
H
Bouletreau
M
M
Vavre
F
F
D000704:Analysis of Variance; D000818:Animals; D004171:Diploidy; D005260:Female; D005838:Genotype; D006238:Haploidy; D006790:Host-Parasite Interactions; D008297:Male; D016133:Polymerase Chain Reaction / Q000379:methods; D011156:Population Density; D012098:Reproduction / Q000502:physiology*; D012744:Sex Ratio; D013045:Species Specificity; D013559:Symbiosis / Q000502:physiology*; D013696:Temperature; D014863:Wasps / Q000382:microbiology*; D020577:Wolbachia / Q000254:growth & development*