The Effects Of Three Pesticides Commonly Used In Paddy Field On The Behaviors Of Pirata Subpiraticus

The wolf spider Pirata subpiraticus Arachnoidea, hunting in the middle and lower parts of the rices, mainly feed on rice planthopper, leafhopper and other pests. In this stage, for the management of rice pests, application of pesticides still occupy a dominant position. The wolf spider also affected by various aspects of chemical pesticides which is one of the important natural enemies of pests in the rice paddies. Therefore, scientific evaluation of chemical pesticide is an important part to choose chemical pesticides reasonablely, protect the spider groups and enhance natural control in paddy fields. In this study, we focus on a wolf spider P. Subpiraticus. The processes of reproductive and cannibalism-predatory behaviors has been investigated in detail. We selected three pesticides, abamectin, chlorantraniliprole and pymetrozine, which are commonly used against rice pest insects in china, studied the sublethal effects of tested pesticides on reproductive, cannibalism-predatory behaviors. The results are as follows:1. The behaviors of P. Subpiraticus.The reproductive behavior process of P. Subpiraticus involves six processes, chemoexplore, courtship, mating, spawning, carrying sacs and carrying spiderlings behavior. Chemoexplore are used by male spiders to detect the female’s location and evaluate female’s reproductive state, and female spiders evaluate the male spiders by the courtship behavior. The chemoexplore and courtship is the key parts before the agreement of females, and the average time of the chemoexplore’s process is 175±59 seconds and the courtship’s process is 7.2±2.7 seconds. The total process of mating can last 5.9±2.0 seconds, and the cannibalism after that maybe one of the index to evaluate the mating behavior which is 38.9±9.6 percent in an hour time. The duration of the spider pregnancy can last 8.2±2.7 days, and its average interval time is 10.9±1.9 days. The process of spawning behavior including four sections, spinning on the ground, spawning, spinning on the egg and packaging. The average time of the carrying sacs is 9.9±0.9 days, and the amount of hatching is 27±11 in one egg sacs. Food abundance can significantly increase the duration of carrying spiderlings. Cannibalism including four kinds of behavior patterns, male, female, carrying sacs and carrying spiderlings behavior patterns, and predatory can divided into hunting and waiting behavior. The wolf spider prey significantly more fruit flies than planthoppers in a day.2. The effects of the three pesticides commonly used in paddy field on reproductive behavior of P. Subpiraticus.The effects of the three pesticides commonly used in paddy field on courtship, mating, spawning, hatching is different. The results shows that, the recommended dose of abamectin significantly reduced the mating time of spiders molting in 15 days and increased the pregnancy time of spiders molting in 10 or 20 days, and can also increase the pregnancy time of spiders which only the male spiders are dealt with pesticides. Chlorantraniliprole significantly reduced the mating time of spiders molting in 15 or 20 days and the courting time of spiders molting in 20 days, and can reduce the mating time of spiders which only the male spiders are dealt with pesticides. Pymetrozine significantly reduced the mating time of spiders molting in 15 or 20 days. The three pesticides commonly used in paddy field significantly reduced the rate of cannibalistic death and hatching rate, but had no effect on the rate of courting repeatedly and the rate of success mating.3. The effects of the three pesticides commonly used in paddy field on cannibalism-predatory behavior of P. Subpiraticus.The results shows that, the recommended dose of abamectin significantly reduced the attack frequency in 30 minutes, and increase the latency to attack. Chlorantraniliprole also significantly reduced the attack frequency in 30 minutes, but had no effect on the Latency to attack. Pymetrozine only significantly reduced the attack frequency of the males in 30 minutes. The death of females’cannibalism mainly occurred in five days, but males’death usuusually occurred after ten days. After the application of abamectin and chlorantraniliprole, the death of cannibalism was increased, but pymetrozine decreased the death of cannibalism. The recommended dose of the three pesticides commonly used in paddy field were significantly reduced the attack frequency, prey and the active time.