National Centre for Vector Entomology, Institute of Parasitology, Vetsuisse and Medical Faculty, University of Zürich, Winterthurerstr. 266A, 8057, Zurich, Switzerland.
Sci Rep. 2024 Jun 5;14(1):12959. doi: 10.1038/s41598-024-63625-4.
Temperature is a critical factor shaping physiology, life cycle, and behaviour of ectothermic vector insects, as well as the development and multiplication of pathogens within them. However, the influence of pathogen infections on thermal preferences (behavioural thermoregulation) is not well-understood. The present study examined the thermal preferences of mosquitoes (Aedes aegypti and Ae. japonicus) infected with either Sindbis virus (SINV) or Dirofilaria immitis over 12 days post exposure (p.e.) or injected with a non-pathogenic Sephadex bead over 24 h in a thermal gradient (15-30 °C). SINV-infected Ae. aegypti preferred 5 °C warmer temperatures than non-infected ones at day 6 p.e., probably the time of highest innate immune response. In contrast, D. immitis-infected Ae. japonicus preferred 4 °C cooler temperatures than non-infected ones at day 9 p.e., presumably a stress response during the migration of third instar larvae from their development site to the proboscis. Sephadex bead injection also induced a cold preference in the mosquitoes but to a level that did not differ from control-injections. The cold preference thus might be a strategy to escape the risk of desiccation caused by the wound created by piercing the thorax. Further research is needed to uncover the genetic and physiological mechanisms underlying these behaviours.
温度是影响变温节肢动物媒介昆虫生理、生命周期和行为以及病原体在其中发育和繁殖的关键因素。然而，病原体感染对热偏好（行为体温调节）的影响还不太清楚。本研究在 12 天接触后（p.e.）或在热梯度（15-30°C）中 24 小时内注射非致病性葡聚糖珠后，检查了感染辛德毕斯病毒（SINV）或犬恶丝虫（Dirofilaria immitis）的蚊子（埃及伊蚊和日本伊蚊）的热偏好。SINV 感染的埃及伊蚊在第 6 天 p.e. 时比未感染的更喜欢 5°C 的温暖温度，可能是先天免疫反应最强的时候。相比之下，在第 9 天 p.e.，感染犬恶丝虫的日本伊蚊比未感染的更喜欢 4°C 的凉爽温度，这可能是第三期幼虫从发育部位迁移到喙时的应激反应。葡聚糖珠注射也会引起蚊子的冷偏好，但程度与对照注射没有差异。因此，这种冷偏好可能是一种逃避因刺穿胸部而造成的脱水风险的策略。需要进一步研究来揭示这些行为背后的遗传和生理机制。
