Before analysis, however, male attractiveness was transformed using natural logarithms and average mating duration was transformed using the square root transformation as both were positively skewed.
In both species the average mating duration is 2 4 h (Amano & Chant, 1978b; Enigl & Schausberger, 2004; Gotoh & Tsuchiya, 2008).
Mating duration was negatively correlated with male body size and male age, being shorter in small and old males, respectively.
The total mating duration was significantly shorter for NG males compared with males that offered a gift (F = 10.03, p < 0.0001, df = 3, Figure 2A).
Though Jhe and clt males mated with females, they had a significant (p < 0.05) increase in mating latency (Fig. 5) (ANOVA, genotype p < 0.05, trial p > 0.05), while mating duration was unaffected.
The mean mating duration was not significantly different in first and in second mating, independently from genotype and order of both males (Kruskal-Wallis test,χ2 = 8.12, d.f. = 5, p = 0.1).
In the reciprocal cross, mating occurrences were not different than in the parental strains, but mating duration was about double, again with the male having observed difficulty disengaging from the female.
Mating duration was measured from the beginning of the first to the end of the last pedipalp insertion and included the time the male and female were in face-to-face position and handled the gift.
Sperm quantity is considered to be a function of male body size (Fox, McLennan & Mousseau, 1995; Schlüns et al., 2003), and mating duration is an appropriate indicator of the amount of transferred sperm in several species (e.g. Arnqvist & Danielsson, 1999; Wilder & Rypstra, 2007), including P. persimilis and N. californicus (Amano & Chant, 1978a; Gotoh & Tsuchiya, 2008).
Courtship duration, time to first courtship, time to mating, and copulation duration were analyzed with GLMs with an inverse link function and errors following a gamma distribution.
