Survival
Pupae were collected from stock vials within 24 hours of pupation,
allocated to vials of 20 pupal flies. Three vials were allocated to each
treatment (giving 60 flies total per treatment, ~30
males, as sex cannot be determined in young pupae). These vials were
randomly assigned to 3D-printed floating racks into pre-heated water
baths (Grant TXF200) for 1 hour at either a control non-hardening
temperature at 23°C (‘no hardening’) or a range of hardening
temperatures (‘hardening’: 34, 35 & 36°C). These are non-lethal pupal
temperatures that also do not significantly sterilise males (Walshet al. 2020). After this hardening treatment, they were
immediately moved into different pre-heated water-baths for 4-hours at
either 23°C (‘benign’) or at a range of sub-lethal to lethal
temperatures between 37 - 41°C (‘stress’). Immediately following
treatment, vials were returned to benign conditions (23°C) and emerging
individuals were collected and sexed. This allowed us to assess survival
of pupae at extreme temperatures, and gave us an idea of whether
survival may be sex specific. However, as we were unable to determine
the sex of the pupae prior to stress, we could not explicitly test for
sex differences in survival thermal tolerance.