Response of life‐history traits to artificial and natural selection for virulence and nonvirulence in a Drosophila parastitoid, Asobara tabida

Abstract

Co-evolution of host-parasitoid interactions is determined by the costs of host resistance, which received empirical evidence, and the costs of parasitoid virulence, which have been mostly hypothesized. Asobara tabida is a parasitoid, which mainly parasitizes Drosophila melanogaster and D. subobscura, the first species being able to resist to the parasitoid development while the second species is not. To parasitize resistant hosts, including D. melanogaster, A. tabida develops sticky eggs, which prevent encapsulation, but this virulence mechanism may be costly. Interindividual and interpopulation variation in the proportion of sticky eggs respectively allowed us to (i) artificially select and compare life-history traits of a virulent and a nonvirulent laboratory strain, and (ii) compare a virulent and a nonvirulent field strain, to investigate the hypothetical costs of virulence. We observed strong differences between the 2 laboratory strains. The nonvirulent strain invested fewer resources in reproduction and walked less than the virulent one but lived longer. Concerning the field strains, we observed that the nonvirulent strain had larger wings while the virulent one walked more and faster. All together, our results suggest that virulence may not always be costly, but rather that different life histories associated with different levels of virulence may coexist at both intra- and interpopulation levels.

Variation in the Venom of Parasitic Wasps, Drift, or Selection? Insights From a Multivariate QST Analysis

“…However, changes have occurred over the past 30 years in the community with L. boulardi moving northward rapidly (90 km per decade), probably in relation to the increase in temperature associated with global warming (Delava et al, 2014). The presence of this new competitor affects the life history traits of A. tabida (Vayssade et al, 2012;van Baaren et al, 2016;Moiroux et al, 2018) but not L. heterotoma, possibly due to a wider overlap of its ecological niche with that of A. tabida (Vayssade et al, 2012).…”

Geographic variation in resistance of the invasiveDrosophila suzukiito parasitism by the biological control agent,Ganaspis brasiliensis

“…This indicates that it is not solely interactions between parasitoids and hosts that can lead to changes in these important traits, but that the environmental effects on a host-parasitoid community may play a role as well. Both host resistance and parasitoid virulence can also evolve rapidly (Jalvingh et al, 2014;Cavigliasso et al, 2019;Moiroux et al, 2018), and the maintenance of both can be costly (Fellowes et al, 1998;Kraaijeveld & Godfray, 2002;Kraaijeveld & Godray, 1997;Kraaijeveld et al, 2001).…”