United States Department of Agriculture-Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, 9611 South Riverbend Avenue, Parlier, CA 93648, USA.
School of Mechanical, Industrial, and Manufacturing Engineering, Collaborative Robotics and Intelligent Systems Institute, College of Engineering, Oregon State University, 101 Covell Hall, Corvallis, OR 97331, USA.
Environ Entomol. 2023 Apr 18;52(2):169-174. doi: 10.1093/ee/nvad003.
Female black widow spiders, Latrodectus hesperus Chamberlin and Ivie (Araneae: Theridiidae), are solitary predators of arthropods with no tolerance for intruders on the webs. In California, L. hesperus are found in urban and agricultural settings and can be a phytosanitary pest in fresh produce. Spatial separation of L. hesperus webs could be determined by seasonal population densities, with territorial competition expected under high densities in the environment. However, little is known about female-female communication behaviors in this species. In 1-hr laboratory observations, displays of female-female rivalry included production of vibrational signals in a majority (20 of 30) of trials. The number of signals produced by both females was highest during the initial 10 min of trials, with signaling rate (time interval between signals) peaking during the 40-50 min observation period. The overall ratio of signals produced by the resident female and the introduced female was about 5:1, with the number of signals produced by the resident female higher than the number of signals produced by the introduced female. Analysis of rivalry signals showed a peak in magnitude (about 0.4 m/s) ranging from 6 to 23 Hz and smaller peaks at about 29, 38, and 47 Hz. Collectively, these results demonstrate that female L. hesperus exhibit territorial rivalry and that female-female rivalry is mediated by emission of vibrational signals through the web. Understanding the mechanisms of intraspecific competition in L. hesperus is required for elucidating interspecific interactions in the environment and may lead to development of novel methods to prevent spiders from colonizing crops.
雌性黑寡妇蜘蛛（Latrodectus hesperus Chamberlin and Ivie）是独居的节肢动物捕食者，对蛛网入侵者没有容忍度。在加利福尼亚州，L. hesperus 存在于城市和农业环境中，并且可能成为新鲜农产品的植物卫生害虫。L. hesperus 蛛网的空间分离可能由季节性种群密度决定，预计在环境中高密度下会出现领地竞争。然而，对于该物种的雌性间通讯行为知之甚少。在 1 小时的实验室观察中，包括在大多数（30 次试验中的 20 次）试验中产生振动信号在内的雌性间竞争行为都有显示。两只雌性产生的信号数量在试验的最初 10 分钟内最高，信号率（信号之间的时间间隔）在 40-50 分钟的观察期内达到峰值。居留雌性和引入雌性产生的信号总数之比约为 5:1，居留雌性产生的信号数量高于引入雌性产生的信号数量。对竞争信号的分析显示，在 6 至 23 Hz 范围内幅度峰值（约 0.4 m/s）和在约 29、38 和 47 Hz 处的较小峰值。总体而言，这些结果表明雌性 L. hesperus 表现出领地竞争，并且雌性间竞争是通过蛛网振动信号的发射来介导的。了解 L. hesperus 种内竞争的机制对于阐明环境中的种间相互作用是必要的，并且可能导致开发防止蜘蛛殖民作物的新方法。
