浅斑近微蛛体形大小对交配行为的影响

理论和实验表明体形大小是许多动物择偶的重要信号。体形大小与产卵大小、最终产卵数量、后代适合度等都有着密切的关系,因此动物利用体形大小为信号来择偶可以获得高的生殖利益。目前研究交配行为和体形大小的关系的文献较少,特别在微蛛亚科。本文以浅斑近微蛛为实验材料,在室内研究了体形大小对交配行为的影响。测量了体重,体长,头胸甲与腹部的长和宽,以头胸甲的面积(头胸甲的长与宽的乘积)为变量来表示体形大小。以雄蛛的行为为依据,将其交配行为划分为4个时期:潜伏期、求偶期、插入期和纳精期,并记录了各个时期的持续时间。通过分析,发现了一种微蛛新的交配模式,即可将浅斑近微蛛的插入期分为三个阶段:首先是大约25min长插入期,接着是一个大约15min的中度插入期,最后是一个大约5min的短插入期。结果表明,在本试验条件下,浅斑近微蛛的体形大小对其交配行为的潜伏期、求偶期、插入期和纳精期的持续时间都没有影响,对插入期的3个阶段的长短也没有影响。

Effect of Body Size on Mating Behavior of the Dwarf Spider Eperigone fradeorum (Araneae,Linyphiidae)

Theoretical and empirical studies suggest that body size is an important signal used by many animals to measure the quality of their mates. Animals choosing larger mates benefit reproductive fitness via volume of egg load,proximity of oviposition and offspring fitness,etc. Literature on relationship between body size and mating behavior is scarce,especially in dwarf spider. We investigated the relation between body size and mating behavior of the dwarf spider,Eperigone fradeorum,under laboratory condition. Body mass,body length,carapace length and width,abdomen length and width were measured. Body size was measured by area of carapace(the carapace width was multiplied by its length). We grouped the mating behavior into four phases which defined by males' behavior:latency,courtship,insertion and sperm induction. Duration of every phase was recorded. An unusual pattern of male pedipalps inserting duration during copulation was discovered. The insertion had three phases which grouped by the duration of pedipalps inserting. Initial long inserting duration about 25 min was followed by a medium inserting duration(15min or so); however,subsequent short inserting decreased to approximately 5 min in duration.The results showed that body size had no influence on duration of latency,courtship,insertion,sperm induction and three phases in inserting duration.