Copulation duration was measured from the beginning of copulation to the end of it, when the male fully disengaged from the female.
Copulation calls consist of a rhythmic succession of high-frequency squeaks or screams and typically begin during the copulation, after mounting and intromission (fig 5).
In several species, sperm is known to be transferred only at the very beginning of copulation, while during the later stages of copulation males transfer substances that build effective mating plugs or other manipulating seminal fluids [ 24, 25].
By contrast, the courtship index CI is defined as the fraction of time the male spent courting from the beginning of observation until copulation or the end of observation at 10 minutes.
Moreover, some additional pairs were interrupted 30 (n = 5), 60 (n = 10), 120 (n = 7) and 180 min (n = 6) after the beginning of copulation and females were dissected to count the amount of stored sperm.
Mating latency (defined here as the time between the beginning of courtship and the start of copulation) increased with female age, and copula duration was found to decrease as females aged.
Also, the fact that females produced eggs after copulations lasting less than required for sperm transfer to occur (90 s) might be attributed to the action of fecundity-enhancing seminal fluids transferred at the very beginning of copulation, even before sperm transfer begins.
Under this scenario, mating would have been concentrated at the beginning of the observation period, and the per female copulation rate estimate would be close to one.
Courtship duration was measured from the beginning of courtship to the onset of copulation, when the male mounted the female and locked genitalia.
Benefits of stabilizing the copulation and intromission are indicated as the driving force for the evolution of extremely long aedeagi, while the short aedeagi might have the advantage of freedom of movements facilitating the initiation of copulation by males.
For each of the 8 males we compared the copulation of the pedipalp used during the first copulation.
