Mating success
Immediately following short-term (24h) exposure of experimental males to
females cues (or control), we set up 317 triplets consisting of: a
female-exposed wt male, a control wt male and a standardwt female. All three individuals were 4 day-old virgins at the
start of the mating trials. To distinguish between female-exposed and
control males, we marked both males with a dot of acrylic paint on the
backside of their thorax using either of two easily discernable colours
(Vallejo acrylic studio; cadmium red hue N°2 “PCKPCQL” or primary blue
N°24 “PBN4CQK”). We haphazardly alternated assignment of colour to
either treatment as a mean to balance any potential colour-induced bias
in the behaviour of reproducing females and/or focal males. We used
systematic scan sampling to record male mating success (which of the two
males mated with the female), mating latency (time between the start of
mating trials and the beginning of a successful copulation), as well as
mating duration (length of a successful copulation by either male). We
only considered a mating as successful if it lasted longer than 10
minutes (unpublished results show that this provides a conservative
threshold for successful matings in this population). We ensured a
one-minute resolution in the measurement of these variables by limiting
the number of vials each of the two observers handled at the time.
Observations were conducted following a blind protocol. After a
successful mating, we discarded both males, but kept mated females alone
in the vial for later experiments (see below). We gave females a total
of 150 minutes to mate with either of the two males, after which we
discarded all females that had not mated; a large proportion of the
females mated with either of the two males (ca. 86%; 273 successful
matings were recorded, out of 317 triplets set). Females that mated with
a female-exposed male are hereafter called treatment females ,
whereas females that mated with a control male are called control
females .