Evolution of dispersal syndrome and its corresponding metabolomic changes

Abstract

Dispersal is one of the strategies for organisms to deal with climate change and habitat degradation. Therefore, investigating the effects of dispersal evolution on natural populations is of considerable interest to ecologists and conservation biologists. Although it is known that dispersal itself can evolve due to selection, the behavioral, life-history and metabolic consequences of dispersal evolution are not well understood. Here, we explore these issues by subjecting four outbred laboratory populations of Drosophila melanogaster to selection for increased dispersal. The dispersal-selected populations had similar values of body size, fecundity, and longevity as the nonselected lines (controls), but evolved significantly greater locomotor activity, exploratory tendency, and aggression. Untargeted metabolomic fingerprinting through NMR spectroscopy suggested that the selected flies evolved elevated cellular respiration characterized by greater amounts of glucose, AMP, and NAD. Concurrent evolution of higher level of Octopamine and other neurotransmitters indicate a possible mechanism for the behavioral changes in the selected lines. We discuss the generalizability of our findings in the context of observations from natural populations. To the best of our knowledge, this is the first report of the evolution of metabolome due to selection for dispersal and its connection to dispersal syndrome evolution.

The distinct phenotypic signatures of dispersal and stress in an arthropod model: from physiology to life history

“…S2 for fecundity at 24 h). Our findings in the one-generation experiment are similar to those of Tung et al (2018) in Drosophila melanogaster after several generations of selection for dispersal. They suggested that identical body size and fecundity despite the constitutive and induced costs of dispersal was offset by a shorter lifespan; our experiment was not designed to test this hypothesis.…”

“…Among the few dispersal metabolomics studies published, van Petegem et al 2016found that more dispersive populations were characterized by lower concentrations in fructose, as well as lower activities of metabolic pathways associated with protein synthesis (as depicted by the lower amounts of a range of amino acids), the latter suggesting a reduced investment towards egg production in dispersive females. Meanwhile, Tung et al (2018) reported an increased aerobic metabolism (higher amounts of glucose AMP and NAD) in flies selected for enhanced dispersal abilities. These differences may be explained by dispersers investing more than residents in dispersal-related traits to mitigate dispersal costs, which may lead them to have fewer resources to allocate to reproduction and to stress resistance mechanisms (Bonte et al, 2012), especially if dispersal and stress responses share metabolic pathways.…”

Sex differences in dispersal syndrome are modulated by environment and evolution

“…For this experiment, we used VB (dispersal-selected) populations and their corresponding control and ancestral populations, VBCs ( [42,46], see electronic supplementary material, figure S3 and text S1.6). At the time of this study, these flies had undergone selection for dispersal for 70 generations.…”

“…In order to circumvent these issues, we used a different approach to assess the evolutionary dispersal syndrome. Like many other Drosophila life-history evolution experiments (for example, see [46,47]), we compared the VBs with their corresponding controls (VBCs), which have been maintained and evolved in parallel to these populations. Except for the selection for dispersal, the VBCs have undergone identical maintenance as the VBs (including the duration of desiccation stress faced by VBs during dispersal).…”

“…VB 4 if analysed this way, day-to-day environmental variations (since the three experiments were conducted on separate days) would be confounded with experiment identity, thereby increasing the noise in the data. This is the reason for which, in the Drosophila life-history literature, such experiments are typically performed with a blocked design, such that the effects of day-to-day variations can be explicitly accounted for using a mixed-model ANOVA (for example, see [46,47]). In the context of our study, that would mean that one replicate for each experiment (1/2/3) should have been performed on the same day, and this entire thing should have been repeated on multiple days to get the desired number of replicates.…”