Graduate School of Agriculture, Kindai University, Nakamachi 3327-204, Nara 631-8505, Japan.
Research & Development Center, Toa Corporation , Anzencho 1-3, Tsurumi-ku, Yokohama, Kanagawa 230-0035, Japan.
J Econ Entomol. 2021 Dec 6;114(6):2460-2465. doi: 10.1093/jee/toab189.
Strategic responses to invasive Latrodectus widow spiders are a global challenge due to the risks they pose to health and ecosystems. Chemical strategies involving the use of pyrethroids are effective against adult spiders, but as their populations rebound, chemical control becomes costly and unsustainable for eradication. A major obstacle is the inefficacy of insecticides against eggs, which are covered by a protective silk egg sac. Eradication of invasive spiders must focus on destroying progeny. Here, the responses of eggs in egg sacs of two invasive Latrodectus spiders in Japan (Latrodectus hasseltii (Thorell) and Latrodectus geometricus (C.L. Koch)) to short-term dry-heat exposure were examined. To test whether the dry-heat tolerance of the egg sacs of both spider species differed, lethal temperature (LT) was determined based on the hatching rate of eggs from egg sacs subjected to a range of temperatures. Hatching in both species failed completely when the egg sacs were exposed to temperatures of 55°C and above for 10 min, but the LT to reduce hatching by 90% (LT90) differed significantly between L. hasseltii (50. 9°C) and L. geometricus (52. 8°C). Our study highlights the efficacy of dry heat in suppressing hatching and thus shows the possibility for effective extermination of these noxious invasive pests. Further exploration and investigation of the effects of humidity and heat exposure time on egg sacs under field conditions are needed to guide Latrodectus spider control strategies.
由于入侵的黑寡妇蜘蛛对健康和生态系统构成的风险，针对它们的战略对策是全球性的挑战。涉及使用拟除虫菊酯的化学策略对成蛛有效，但随着它们的数量反弹，化学控制变得昂贵且无法持续用于根除。一个主要障碍是杀虫剂对卵的效果不佳，卵被一层保护性的丝质卵囊覆盖。根除入侵蜘蛛必须集中精力破坏后代。在这里，研究了日本两种入侵黑寡妇蜘蛛（Latrodectus hasseltii（Thorell）和 Latrodectus geometricus（C.L. Koch））卵囊中的卵对短期干热暴露的反应。为了测试两种蜘蛛的卵囊的干热耐受性是否不同，根据卵囊中卵的孵化率确定了致死温度（LT），卵囊暴露在一系列温度下。当卵囊暴露在 55°C 及以上温度 10 分钟时，两种物种的卵均完全孵化失败，但 LT90（降低孵化率 90%的温度）在 L. hasseltii（50.9°C）和 L. geometricus（52.8°C）之间存在显著差异。我们的研究强调了干热在抑制孵化方面的功效，因此表明有效消灭这些有害入侵害虫的可能性。需要进一步探索和调查在田间条件下湿度和热暴露时间对卵囊的影响，以指导黑寡妇蜘蛛的控制策略。
