Abstract:
Heatwaves are increasing in frequency and intensity due to climate change, pushing animals beyond physiological limits. While most studies focus on survival limits, sublethal effects on fertility tend to occur below lethal thresholds, and consequently can be as important for population viability. Typically, male fertility is more heat-sensitive than female fertility, yet direct comparisons are limited. Here, we measured the effect of experimental heatwaves on tsetse flies, Glossina pallidipes, disease vectors and unusual live-bearing insects of sub-Saharan Africa. We exposed males or females to a 3-day heatwave peaking at 36, 38 or 40°C for 2 h, and a 25°C control, monitoring mortality and reproduction over six weeks. For a heatwave peaking at 40°C, mortality was 100%, while a 38°C peak resulted in only 8% acute mortality. Females exposed to the 38°C heatwave experienced a one-week delay in producing offspring, whereas no such delay occurred in males. Over six weeks, heatwaves resulted in equivalent fertility loss in both sexes. Combined with mortality, this lead to a 10% population decline over six weeks compared to the control. Furthermore, parental heatwave exposure gave rise to a female-biased offspring sex ratio. Ultimately, thermal limits of both survival and fertility should be considered when assessing climate change vulnerability.
摘要:
由于气候变化,热浪的频率和强度都在增加,推动动物超越生理极限。虽然大多数研究都集中在生存极限上,对生育率的亚致死效应往往发生在致死阈值以下,因此对人口生存能力也同样重要。通常,男性生育力比女性生育力更热敏感,然而,直接比较是有限的。这里,我们测量了实验热浪对采采蝇的影响,苍白条,撒哈拉沙漠以南非洲的病媒和不寻常的活昆虫。我们将雄性或雌性暴露于3天的热浪中,最高温度为36、38或40°C,持续2小时,和25°C控制,在六周内监测死亡率和生殖。对于在40°C达到峰值的热浪,死亡率为100%,而38°C的峰值仅导致8%的急性死亡率。暴露在38°C热浪中的雌性后代推迟了一周,而男性没有这种延迟。六个多星期,热浪导致两性同等的生育率下降。加上死亡率,与对照组相比,这导致在六周内人口下降了10%。此外,父母的热浪暴露导致了女性偏见的后代性别比。最终,在评估气候变化脆弱性时,应考虑生存和生育的热极限。