For a successful copulation to occur, cooperation between the female and male is required.
In addition to swelling size, we noted the following variables: identity of mating partners, presence/absence of copulation call, temporal occurrence of call in relation to copulation, aggressive behaviours following a copulation, duration to next copulation and composition of the audience during copulation.
As female cooperation is an essential prerequisite for copulation to occur in D. montana [ 54], remating is likely an adaptively favoured female strategy, rather than an inability to physically resist coercive manipulation.
This finding is supported by our final experiment, where we found a significant correlation between the "copulation to no engagement" transition probability and copulation duration in an independent assay with a different female genotype.
Despite these experimental differences, we identified a slight but significant negative relationship (r = 0.35, P = 0.047) between copulation duration and the probability of transitioning from "copulation" to "no engagement" (E to A) in these 35 lines.
The transition with the greatest heritable variation was "copulation" to "no engagement" (E to A, Table 3).
Second, prolonged copulation might be a method of mate-guarding, because the mates would normally segregate after copulation to form unisexual groups which persist throughout the non-breeding season [29].
Amazons have a copulation pattern similar to that found in other parrots throughout the Americas, with the male gripping a perch with one leg while passively placing the other in the female's back.
In either case, the data does not strongly link petal-carrying and presenting to a copulation soon thereafter.
Detection of a copulation plug was performed to confirm successful mating.
