State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, P.R. China.
Malheur Experiment Station, Oregon State University, 595 Onion Avenue, Ontario, Oregon, 97914, USA.
Sci Rep. 2019 Sep 20;9(1):13625. doi: 10.1038/s41598-019-49950-z.
Behavioral thermoregulation is a defensive strategy employed by some insects to counter infections by parasites and pathogens. Most reported examples of this type of thermoregulatory response involve behavioral fevering. However depending upon the life history of a host-insect and that of the parasite or pathogen, the host may respond by cold-seeking behavior. Thermoregulation is not only ecologically important; it may affect the success of parasites and pathogens as biological control agents. We examined if Frankliniella occidentalis (Pergande) thermoregulates in response to infection by Beauveria bassiana, a fungal pathogen commonly used for biological control. Fungal-infected thrips preferentially moved to cooler areas (12 °C) while healthy thrips sought out warmer temperatures (24 °C). This cold-seeking behavior suppressed the growth of B. bassiana in infected thrips, and significantly improved survivorship of infected thrips. At 24 °C, males only survived up to 10 d after infection and females up to 20 d after infection, which was substantially poorer survivorship than that of corresponding healthy individuals. However, individuals of both sexes survived up to 48 d after infection at 12 °C, which was a much less severe reduction in survivorship compared with the effect of B. bassiana infection at 24 °C. The proportion of females among progeny from infected thrips at 12 °C was higher than at 24 °C. Therefore, cold-seeking behavior is beneficial to F. occidentalis when infected by B. bassiana, and its effects should be considered in the use of B. bassiana in biological control programs.
行为体温调节是一些昆虫用来对抗寄生虫和病原体感染的防御策略。大多数报道的这种类型的体温调节反应的例子都涉及行为发热。然而，根据宿主昆虫的生活史和寄生虫或病原体的生活史，宿主可能会通过冷寻求行为做出反应。体温调节不仅在生态上很重要；它可能会影响寄生虫和病原体作为生物防治剂的成功。我们检查了西方花蓟马（Frankliniella occidentalis (Pergande)）是否会因被一种常用于生物防治的真菌病原体——球孢白僵菌（Beauveria bassiana）感染而调节体温。感染的蓟马更喜欢移动到较冷的区域（约 12°C），而健康的蓟马则寻求较温暖的温度（约 24°C）。这种冷寻求行为抑制了感染蓟马中 B. bassiana 的生长，并显著提高了感染蓟马的存活率。在 24°C 时，雄性感染后仅能存活 10 天，而雌性感染后仅能存活 20 天，这比相应健康个体的存活率差得多。然而，在 12°C 时，无论是雄性还是雌性，在感染后都能存活长达 48 天，与在 24°C 时 B. bassiana 感染的影响相比，这是存活率大幅降低。在 12°C 时，来自感染蓟马的后代中雌性的比例高于 24°C。因此，当西方花蓟马被球孢白僵菌感染时，冷寻求行为对其有益，在使用球孢白僵菌进行生物防治计划时应考虑其影响。
