Peanut red spider mite, Tetranychus ogmophallos, exhibits a peculiar dispersal behavior using silk balls, which involves clustering of mites and spinning of webs at the top of plants. Such a dispersal mechanism has not been studied for this species yet. Therefore, this study aimed at using mathematical models to describe aerial dispersal and silk ball formation of peanut red spider mite on peanut plants. The influence of wind speed, generated by a wind tunnel, on the dispersal of mites was studied in two experiments, one with 500 mites per plant and one with 1000 mites per plant, and six wind speeds (5, 10, 15, 20, 25, and 30 km h⁻¹) for each mite density. The proportion of displaced mites and the distance they were blown were measured. Another series of experiments considered the formation of silk balls to assess how fast balls were formed as a function of time and the number of mites present on a peanut plant. Data from the wind tunnel experiments were analyzed by logistic regression and multiple regression to assess the proportion of displaced mites and the distance moved, respectively, as functions of wind speed and the initial density of mites on the donor plant. The distribution of dispersal distances from the donor plant was fitted by a mathematical model proposed by Ricker (J Fish Res Board Can 11:559–623, 1954). The number of mites moving upwards on a plant to be involved in silk ball formation was modeled as a function of time based on the initial number of spider mites and their estimated birth, death and movement rates per capita. Logistic regression was used to analyze the presence of balls as a function of time elapsed since a plant was infested with spider mites. Finally, non-linear regression was applied to link ball size to the total number of mites occupying the ball. The data analyses revealed that wind speed had a significant positive effect on take-off probability and distance moved by individual mites, whereas mite density had little influence. Ricker’s model adequately described the distribution of dispersal distances. The models describing silk ball formation also described data very well. Ball size was found to increase almost linearly with the number of mites found in the ball. We expect that the knowledge provided by the present study will help to develop efficient management strategies against T. ogmophallos in peanut crops as dispersal seems to be a key factor in the species’ capability to become a serious pest.

中文翻译：

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使用数学模型描述花生红蜘蛛螨（Tetranychus ogmophallos（Acari：Tetranychidae））的空中扩散和绢球形成。

花生红蜘蛛螨Tetranychus ogmophallos通过丝球表现出特殊的分散行为，这涉及螨的聚集和植物顶部的网的旋转。尚未对该物种研究这种扩散机制。因此，本研究旨在使用数学模型来描述花生植物上花生红蜘蛛的空中扩散和绢球形成。在两个实验中研究了风洞产生的风速对螨虫传播的影响，其中一个实验每棵植株有500颗螨虫，另一种每棵植株有1000颗螨虫，并且有六种风速（5、10、15、20， 25和30 km h ^-1）的每种螨虫密度。测量了螨虫的比例及其吹出的距离。另一系列实验考虑了丝球的形成，以评估形成球的速度与时间的关系，以及花生植物上螨虫的数量。通过逻辑回归和多元回归分析了风洞实验的数据，以评估螨的比例和移动的距离，分别作为风速和供体植物螨的初始密度的函数。Ricker提出的数学模型（J Fish Res Board Can 11：559–623，1954年）拟合了距供体植物的散布距离分布。基于蜘蛛螨的初始数量及其估计的人均出生，死亡和移动速度，将要参与形成丝球的植物上向上移动的螨数量建模为时间的函数。自植物感染红蜘蛛以来，使用逻辑回归分析分析球的存在与时间的关系。最后，应用非线性回归将球的大小与占领球的螨虫总数联系起来。数据分析表明，风速对单个螨的起飞概率和移动距离具有显着的积极影响，而螨的密度几乎没有影响。里克模型充分描述了分散距离的分布。描述丝绸球形成的模型也很好地描述了数据。发现球的大小几乎随球中螨的数量线性增加。我们希望本研究提供的知识将有助于制定有效的管理策略来应对花生作物中的T. ogmophallos扩散似乎是该物种成为严重害虫的能力的关键因素。