(a) Sex-ratio reduces girls fecundity
Overall, SR/ST females produce fewer offspring than ST/ST females (Fdos,2 = 7.0, p = 0.0013), and this is significant for each SR strain (SRMyself: t = ?2.9, p = 0.0049; SRNew york: t = ?2.4, p = 0.018). However, there was not a significant difference in the effect of SR strain on female fecundity (SRMyself: 159 ± 8.3 (mean ± s.e.), SRNew york: 174 ± 11.5; F1,1 = 3.7, p = 0.056). Across both SR strains combined, SR/ST females produced an average of 165 ± 6.7 offspring (n = 74) whereas ST/ST females produced an average of 197 ± 6.1 offspring (n = 66), a 16.3% reduction in fecundity (95% CI 0.074–0.245).
Figure 1. Female fecundity of SR carriers is reduced when compared with wild-type females. Two different SR chromosomes were assayed (SRMe and SRNew york) in heterozygous females, and each was compared to wild-type (ST/ST) females with an otherwise similar genetic background. The dark line in the box indicates the median and the bottom and top of the box indicate the first and third quartiles, respectively. (Online version in colour.)
(b) Zero effectation of intercourse-ratio on the durability
We find segregating variation for longevity, but we do not find that SR carriers show reduced survival relative to ST carriers. We assayed 2669 flies for longevity, which included female and male carriers of two different SR chromosomes and four different ST chromosomes (electronic supplementary material, table S1). SR carrier status did not contribute significantly to variation in longevity (figure 2; electronic supplementary material, figure S4; females: Wald ? 1 2 = 2.5 , p = 0.1; males: Wald ? 1 2 = 0.8 , p = 0.7), but there was a significant effect of line within chromosome type (females: Wald ? 4 2 = 24 , p = 0.0004; males: Wald ? 4 2 = 3 , p < 0.0001). Within chromosome type, there was no significant difference between the two SR strains (females: Wald ? 1 2 = 0.2 , p = 0.6; males: Wald ? 1 2 = 0.3 , p = 0.6), though there was among ST strains, which is owing to a longer lifespan of the Ny2 line when compared with the other lines (females: Wald ? 1 2 = 6 , p = 0.01; males: Wald ? 1 2 = 13 , p = 0.0004).
Figure 2. The fresh new life of women SR carriers (SR/ST) isn’t reduced in accordance with crazy-kind of (ST/ST) female. Flies was broke up of the filter systems, which included five ST strains and two SR stresses. (On the internet type for the colour.)
(c) Girls do not discriminate up against mating that have gender-proportion people
We do not find evidence that virgin females discriminate against mating with SR males. First, in no-choice trials, females mated at similar rates with SRMyself and ST males (SRMyself: (76%) mated, ST: (82%) mated in 2 h; FET, p = 0.55). Of the pairs that copulated, the mating latency was not significantly different between SRMe and ST males (SRMe personally: 34.0 ± 2.6 min (mean ± s.e.), ST: 29.9 ± 4.5; Wilcoxon rank-sum test, Z = 1.69, p = 0.09; electronic supplementary material, figure S5). Second, we do not find evidence that females discriminate against mating with SR males in situations with the extensive male–male competition. In our cage experiments, none of the three tester male genotypes (ST, SRMyself and SRNew york) showed a consistent difference from 50 : 50 random mating against the dark males (ST: ? 1 MH 2 = 0.18 , p = 0.7; SRMe: ? 1 MH 2 = 0.01 , p = 0.9; SRNY: ? 1 MH 2 = 1.5 , p = 0.2; electronic supplementary material, figure S6).
