Effects of extreme temperature events on the parasitism performance of Diadegma semiclausum, an endoparasitoid of Plutella xylostella

• Published in: Entomologia experimentalis et applicata Vol. 170; no. 8; pp. 656 - 665
• Main Authors: Costaz, Thibault P. M., Gols, Rieta, Jong, Peter W., Loon, Joop J. A., Dicke, Marcel
• Format: Journal Article
• Language: English
• Published: Amsterdam Wiley Subscription Services, Inc 01.08.2022
• Subjects: Body temperature; carry‐over effects; Climate change; Climate prediction; Diadegma semiclausum; Eggs; Endoparasites; Exposure; Extreme weather; extreme weather events; fluctuating temperatures; heat shock; Herbivores; High temperature; host preference; Hymenoptera; Ichneumonidae; Insects; larval endoparasitoid; Lepidoptera; Oviposition; Parasitism; parasitoid; Physiological effects; Physiology; Plutella xylostella; Plutellidae; Temperature; Temperature distribution; Temperature preferences
• ISSN: 0013-8703; 1570-7458
• DOI: 10.1111/eea.13197

With climate change, the occurrence of extreme weather events such as heatwaves is expected to increase. Extreme temperature events are short periods of high temperature (i.e., >95th percentile of temperature distribution), and their occurrences are difficult to predict. These extreme temperature events pose great challenges to living organisms, especially ectotherms such as insects whose body temperature is greatly influenced by environmental temperature. Temperature is known to play an essential role in driving insect performance as well as inducing behavioral changes. Exposure to extreme temperatures causes physiological damage leading to potential long‐lasting effects on insect performance. We aimed at assessing the impact of direct (i.e., current) and indirect (previously experienced) exposure to extreme temperature on the oviposition success of Diadegma semiclausum Hellén (Hymenoptera: Ichneumonidae). Diadegma semiclausum is a larval endoparasitoid of Plutella xylostella L. (Lepidoptera: Plutellidae), a worldwide pest of brassicaceous crops. Oviposition success, measured as the percentage of parasitized P. xylostella, was significantly lower at 33 °C than at 25 °C. However, previous exposure to 33 °C did not significantly impact the egg‐laying performance of D. semiclausum, indicating that, after a heatwave, the egg‐laying performance can recover. Neither the direct nor indirect exposure to extreme temperature altered D. semiclausum host‐instar preference. These results indicate that temperature directly impacts D. semiclausum parasitism performance, although more detailed research is needed to disentangle direct physiological mechanisms from behavioral responses. Overall, these study results confirm others, suggesting that control of P. xylostella by D. semiclausum is likely to be impaired by more frequent heatwaves predicted under climate change scenarios. Due to climate change, the frequency of extreme high‐temperature events (EXT) increases, and exposure to such events can have lasting effects on insect performance. Here we exposed both host and parasitoid to two temperature cycles. After 24 h, we measured parasitism performance at 20, 25, and 33 °C. Parasitoids had lower performance at 33 °C. However, prior EXT exposure did not alter subsequent performance, suggesting a direct effect of temperature and potential heat recovery between the two heat shocks.