Egg Viability, Mating Frequency and Male Mating Ability Evolve in Populations of Drosophila melanogaster Selected for Resistance to Cold Shock

Abstract

BackgroundAbility to resist temperature shock is an important component of fitness of insects and other ectotherms. Increased resistance to temperature shock is known to affect life-history traits. Temperature shock is also known to affect reproductive traits such as mating ability and viability of gametes. Therefore selection for increased temperature shock resistance can affect the evolution of reproductive traits.MethodsWe selected replicate populations of Drosophila melanogaster for resistance to cold shock. We then investigated the evolution of reproductive behavior along with other components of fitness- larval survivorship, adult mortality, fecundity, egg viability in these populations.ResultsWe found that larval survivorship, adult mortality and fecundity post cold shock were not significantly different between selected and control populations. However, compared to the control populations, the selected populations laid significantly higher percentage of fertile eggs (egg viability) 24 hours post cold shock. The selected populations had higher mating frequency both with and without cold shock. After being subjected to cold shock, males from the selected populations successfully mated with significantly more non-virgin females and sired significantly more progeny compared to control males.ConclusionsA number of studies have reported the evolution of survivorship in response to selection for temperature shock resistance. Our results clearly indicate that adaptation to cold shock can involve changes in components of reproductive fitness. Our results have important implications for our understanding of how reproductive behavior can evolve in response to thermal stress.

Evolution of pre- and post-copulatory traits in female Drosophila melanogaster as a correlated response to selection for resistance to cold stress

“…Details of the maintenance of the baseline populations have been explained in our previous study (Singh et al, 2015). Briefly, in 2010, 19 isofemales lines were set up from wild inseminated females of D. melanogaster that were captured from the Blue Ridge Mountains, Georgia, USA.…”

“…A detailed account of the origin and maintenance of the selected (FSB; Cold shock Selected population derived from BRB population) and their control (FCB; Cold shock Control derived from BRB population) populations has been given in our previous study (Singh et al, 2015). In short, after 35 generations of laboratory maintenance of BRB 1-5 populations, we established one FSB and one FCB population from each of the ancestral BRB 1-5 populations.…”

“…Apart from its effects on survival at various life stages, cold shock also affects reproductive traits in both males and females of several insect species (Tucic, 1979, Chen and Walker, 1994, Watson and Hoffmann, 1996, Anderson et al, 2005, Bubliy and Loeschcke, 2005, Colinet and Hance, 2009, Schnebel and Grossfield, 1984, Carriere and Boivin, 1997, Rinehart et al, 2000, Fischer et al, 2003, Jakobs, 2014and Singh et al, 20152016.…”

“…Exposure to cold shock can affect the reproductive output of female D. melanogaster through its direct effects on the survivorship of stored sperm and eggs as well as its indirect effects on female mating propensity and sperm handling. In D. melanogaster, cold shock at sub-zero temperatures leads to the death of stored sperm in mated females (Novitski andRush, 1949 andLefevre andJonsson, 1962) and therefore, they fail to produce progeny (Singh et al, 2015) post cold shock. In fact, mated females can be subjected to cold shock to kill the stored sperm so that these females can be used as virgin females (Lefevre and Jonsson, 1962).…”

“…In fact, mated females can be subjected to cold shock to kill the stored sperm so that these females can be used as virgin females (Lefevre and Jonsson, 1962). Post cold shock, females need to remate and gather sperm afresh in order to produce progeny (Singh et al, 2015). Therefore, mating post cold shock is extremely important for female fitness.…”