Figure 1.

Relationship between the mating history (number of previous copulations) of Nasonia vitripennis males and (a) the lifetime offspring sex ratio (proportion of males) produced by the last mated female, and (b) the pheromone titre. Data are given as means±s.e. Asterisks indicate significant differences between treatments and the control (= 0 previous copulations) at (*) p < 0.05 or (**) p < 0.01 (Kruskal–Wallis H-test and multiple Bonferroni-corrected Mann–Whitney U-tests). Different lowercase letters indicate significant differences at p < 0.05 (one-way ANOVA followed by least significant difference tests).