气候变化领域集成服务门户

Climate change is expected to increase the frequency of periods of extreme weather events, including heat waves that are harmful to arthropod natural enemies. We studied the thermotolerance of the ladybeetle Serangium japonicum Chapin (Coleoptera: Coccinellidae), an important native predator of the whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) in China. Serangium japonicum eggs, first- and fourth-instar larvae, pupae, and adults were subjected to a range of high temperatures (36, 39, 42, 43.5, and 45 degrees C) at intervals between 15 and 720 min. Survival was compromised and declined sharply for all life stages at temperatures of 42 degrees C and higher. First instars were the least heat tolerant, and eggs were typically the most resistant. Egg predation by S. japonicum did not differ whether the adult beetles were subjected to either heat shock or starvation first. Heat shock treatments at 36 degrees C did not impede adult egg consumption, treatments at 39 degrees C crippled ladybeetle's egg consumption for 8 h following treatment but recovered predatory capacity within 24 h after treatment. However, treatments at 42 degrees C greatly impaired ladybeetle's predatory capacity. After experiencing heat shock at 39 and 42 degrees C, adults significantly increased the amount of time they spent resting, which is the probable cause of predation decline after heat exposure. These results demonstrate that short periods of extreme heat exposures have a detrimental impact on S. japonicum survival and predation, but the effect was dependent on duration and life stage. Overall, these findings can help predict population dynamics and success of biological control of whitefly by S. japonicum in a warming world.