Offspring measurements
Time of larviposition was recorded, including whether or not larvae
produced were viable (Baldry et al. 1992). Production of
non-viable offspring was considered a spontaneous abortion (‘abortion’
hereafter). It was not possible to record egg abortions as they were not
visible due to their small size. For pupae collected on a Monday
morning, we consulted the video recordings to determine the exact day of
larviposition (S2 File). For aborted larvae, however, we could not
determine the date for those aborted over the weekend, because early
larval stages were also not visible on the camera and were therefore
recorded as occurring on the Friday. For viable pupae, we measured the
wet weight, to 0.1 mg. Of the pupae produced, we randomly selected 70%
of samples to track emergence. The remaining 30% were destructively
sampled for fat analysis (S2 File) in order to quantify how wet weight
correlates with fat reserves.
Pupae assigned for emergence studies were placed singly into 50 ml
Falcon tubes with a 3 mm hole drilled in the centre of the screw cap to
allow air flow. Pupae were observed daily for date of emergence on
working days and again video recordings were used to determine the date
of emergence on weekends. Pupae were observed for a maximum of 50 days.
Any pupae that had not emerged by 50 days, were recorded as a failed
emergence (Hargrove 2004). Each emerging fly remained in the tube until
it died of starvation. Sex of emerging flies and date of death were
recorded.