Extreme temperatures compromise male and female fertility in a large desert bird

• Published in: Nature communications 2021-02, Vol.12 (1), p.666-10, Article 666
• Main Authors: Schou, Mads F., Bonato, Maud, Engelbrecht, Anel, Brand, Zanell, Svensson, Erik I., Melgar, Julian, Muvhali, Pfunzo T., Cloete, Schalk W. P., Cornwallis, Charlie K.
• Format: Article
• Language: English
• Subjects: 631/158/2165; 631/181/2470; 631/601/1737; 704/158/857; Animal breeding; Animal reproduction; Animals; Biologi; Biological Sciences; Breeding success; Climate change; Desert animals; Ecology; Eggs; Ekologi; Female; Females; Fertility; Fertility - physiology; Fluctuations; High temperature; Hot Temperature; Humanities and Social Sciences; Male; multidisciplinary; Natural Sciences; Naturvetenskap; Reproduction; Science; Science (multidisciplinary); South Africa; Spermatozoa - physiology; Survival; Temperature; Temperature tolerance; Thermal stress; Volatility
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-021-20937-7

Temperature has a crucial influence on the places where species can survive and reproduce. Past research has primarily focused on survival, making it unclear if temperature fluctuations constrain reproductive success, and if so whether populations harbour the potential to respond to climatic shifts. Here, using two decades of data from a large experimental breeding programme of the iconic ostrich ( Struthio camelus ) in South Africa, we show that the number of eggs females laid and the number of sperm males produced were highly sensitive to natural temperature extremes (ranging from −5 °C to 45 °C). This resulted in reductions in reproductive success of up to 44% with 5 °C deviations from their thermal optimum. In contrast, gamete quality was largely unaffected by temperature. Extreme temperatures also did not expose trade-offs between gametic traits. Instead, some females appeared to invest more in reproducing at high temperatures, which may facilitate responses to climate change. These results show that the robustness of fertility to temperature fluctuations, and not just temperature increases, is a critical aspect of species persistence in regions predicted to undergo the greatest change in climate volatility. Climate change may pose a challenge not only for survival of animals but also for their reproduction. Here, Schou et al. analyse how male and female ostrich fertility relates to fluctuating temperature across 20 years, finding reduced fertility away from the thermal optimum, but also individual variation in thermal tolerance.