Effects of heat shock on survival and predation of an important whitefly predator,Serangium japonicum

Abstract

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 °C) at intervals between 15 and 720 min. Survival was compromised and declined sharply for all life stages at temperatures of 42 °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 °C did not impede adult egg consumption, treatments at 39 °C crippled ladybeetle's egg consumption for 8 h following treatment but recovered predatory capacity within 24 h after treatment. However, treatments at 42 °C greatly impaired ladybeetle's predatory capacity. After experiencing heat shock at 39 and 42 °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.

Effects of periodically repeated high‐temperature exposure on the immediate and subsequent fitness of different developmental stages ofPropylaea japonica

“…2, 24,25 For example, Bemisia tabaci Q (Hemiptera: Aleyrodidae) is more heat tolerant than its predaceous coccinellid Serangium japonicum (Coleoptera: Coccinellidae), which may reduce the biological control of B. tabaci by S. japonicum in a warming world. 26 In natural ecosystems, insects often experience diel temperature fluctuations rather than constant temperatures. Moreover, daily maximum temperatures do not occur alone, but high temperatures on 1 day are often associated with high temperatures on subsequent days, leading to heat waves that may last for days, and short periods of extreme temperatures separated by sufficiently long periods of normal temperatures may allow insects to recover before each hot wave.…”

Mortality factors acting on field populations of Bemisia tabaci (Hemiptera: Aleyrodidae) SSA1 on cassava in Uganda

“…The positive impact of air temperature on mortality due to natural enemies may be because of their enhanced ability to suppress pest populations under the temperature ranges observed (Huang et al, 2008). Under warmer temperatures, higher parasitoid reproductive success (Zilahibalogh et al, 2009;Romo & Tylianakis, 2013;Kambrekar et al, 2015) and greater survival of coccinellids (Simmons & Legaspi, 2004;Huang et al, 2008;Yao et al, 2019) have been reported.…”

Contrasting Manual and Automated Assessment of Thermal Stress Responses and Larval Body Size in Black Soldier Flies and Houseflies

“…Even if these thermal tolerance metrics have been linked to the geographical distribution in Drosophila species [ 12 , 34 ], it has been suggested that such simple measures can lack an assessment of biologically relevant performance [ 33 , 35 ]. The performance of mobility and behavioural traits, including walking, flying, and fitness traits such as mating behaviour, may be more ecologically relevant and driven by environmental temperatures, unlike those that drive endpoint traits [ 36 , 37 ]. Furthermore, studies have shown that mobility and behavioural traits show effects of acclimation or hardening treatments not seen when using endpoint metrics in traditional stress tolerance assays [ 22 , 38 ].…”