Materials and Methods
In overview, we test if heat-shocks experienced during pupal and adult
life-history stages result in male sterility. We also test if a brief
period of heat-hardening can ameliorate these effects. In a series of
experiments, adult and pupal male D. virilis were exposed to a 1
hour heat hardening treatment followed immediately by a 4 hour heat
stress, and assayed for survival and fertility over 1-2 weeks to reveal
temporal patterns in fertility loss and restoration. We chose a 4 hour
stress because midday rises to high temperature are relatively common
(Geletič, Lehnert & Jurek 2020), and we think it is ecologically
reasonable that a fly in nature might be exposed to these conditions for
a few hours. Moreover, it is an experimentally tractable time period,
and previous work has demonstrated this method can create male sterility
in many Drosophila species, including D. virilis (Walshet al. 2020; Parratt et al. 2021).