Male competition and the evolution of mating and life-history traits in experimental populations of Aedes aegypti

Abstract

Aedes aegypti is an important disease vector and a major target of reproductive control efforts. We manipulated the opportunity for sexual selection in populations of Ae . aegypti by controlling the number of males competing for a single female. Populations exposed to higher levels of male competition rapidly evolved higher male competitive mating success relative to populations evolved in the absence of competition, with an evolutionary response visible after only five generations. We also detected correlated evolution in other important mating and life-history traits, such as acoustic signalling, fecundity and body size. Our results indicate that there is ample segregating variation for determinants of male mating competitiveness in wild populations and that increased male mating success trades-off with other important life-history traits. The mating conditions imposed on laboratory-reared mosquitoes are likely a significant determinant of male mating success in populations destined for release.

Sexual selection theory meets disease vector control: Testing harmonic convergence as a “good genes” signal inAedes aegyptimosquitoes

“…5C, D; Table 1). Consistent with previous observations in low and high generation colonies [38,40,62], both mother (SD=78.367) and daughter (35.984) first egg clutch size distributions were extremely variable (Table 1) and differed significantly (KW test, P<0.001), with daughters laying 57.66 ± 35.98 eggs, or roughly 54% fewer eggs than mothers, who laid 124.15 ± 78.37 eggs. As with fathers and sons, although mother and daughter size distributions differed (KW test, P=0.004), mothers (2.98 ± 0.10 mm) and daughters (2.93 ± 0.10 mm) were nevertheless of similar size (S3 Fig.…”

“…Importantly, while male mating success was assayed under competitive conditions in the previous work, male harmonic convergence and subsequent mating here occurred in one on one interactions, and a recent study in Ae. aegypti suggests that performance in these two conditions can differ [40]. Future work should address the variation in mating behavior between natural and laboratory adapted populations suggested by these findings.…”

“…This pattern is also suggestive of stabilizing selection [75], which would imply that these traits are regulated by trade-offs with other aspects of fitness, as has been suggested recently in both Ae. aegypti [40] and Anopheles gambiae [76]. However, we cannot rule out the possibility that other reproductive fitness traits not examined here, or perhaps the same traits examined under different environmental conditions [77], would show inheritance consistent with good genes models.…”

“…To investigate the potential of harmonic convergence as an indicator of inherent fitness, we first recorded aerial mating interactions of individual male-female parental pairs and determined their harmonic convergence status [19,20]. Parental pairs and their offspring were maintained separately to examine traits previously used to assess reproductive fitness in this species, including father and son insemination capacity [39], mother first egg clutch size [40], and daughter lifetime egg production and daily survival [41]. In a parallel set of experiments examining the signaling and heritability of male flight performance, we measured parental harmonic convergence outcomes and tested fathers and sons in a novel flight performance assay.…”

Too “sexy” for the field? Paired measures of laboratory and semi-field performance highlight variability in the apparent mating fitness of Aedes aegypti transgenic strains

“…Competitive selective pressures are thought to be high in such rearing environments. Recent experimental evidence indicates that evolutionary responses in mating performance can emerge in as little as five generations in this species [90]. Practically, this would confer a greater advantage to the DsRedKPP males during laboratory mating competition assays, which may explain the discrepancy between the measures of sexual fitness that we observed.…”