Effects Of Sublethal Insecticides And Food On Courtship,mating And Reproduction Of Pardosa Pseudoannulata

The spider community in rice field is very rich in species and quantities,as one of the most important biological regulatory factors in rice pests.Pesticides will not only effectively kill pests in rice fields,but also affect its predatory natural enemies,spiders,in the rice fields with lethal effects and sublethal effects.The sublethal effect of pesticides refers to a series of phenomena in which pesticides do not directly cause death to organisms but affect their way of predation,growth and development,mating and reproduction.With the increase of people’s requirements for food safety and environmental quality,researches on the sublethal effects of pesticides on natural enemies of pests also increase.In order to improve the integrated pest control effect of the paddy field ecosystem,two strategies,pesticide control and natural enemy control,should be used in coordination.Pesticides that are highly toxic to rice field pests but have little impact on the natural predators of pests should be selected to maximize the synergistic control effect.Studies have shown that some sublethal doses of chemical pesticides can not only effectively kill pests,but also do less damage to predatory spiders.Pardosa pseudoannulata(Araneae: Lycosidae)is an important predatory natural enemy of common pests in rice field ecosystems.It has large size individuals,abundant population,and a strong ability to prey on rice pests.In this experiment,Pardosa pseudoannulata was selected as the research object,and the commonly used pesticides(emamectin benzoate and abamectin)in rice fields were selected as the main reagents.The filter paper culture dish method was used to explore sublethal effects of these two insecticides on courtship,mating,and reproduction of Pardosa pseudoannulata,aiming to provide scientific basis for coordinating the chemical and biological control of pests in rice fields.At the same time,single food(Drosophila melanogaster)and mixed food(Drosophila melanogaster and Musca domestica)were fed separately to explore the effects of food on courtship,mating and reproduction of Pardosa pseudoannulata.The main results of the experiment are as follows:The sublethal dose of emamectin benzoate has no significant effect on the latency to courtship,courtship intensity,mating success rate,mating duration,latency to egg laying,the rate of egg cannibalism,latency to egg hatching,and the number of spiderlings.On the other side the sublethal dose of abamectin can significantly shorten the mating duration and reduce the mating success rate of Pardosa pseudoannulata.However,there was no significant effect on male’s latency to courtship,courtship intensity,and female’s latency to egg laying,the rate of egg cannibalism,latency to egg hatching,the number of spiderlings.Single food and mixed food feeding have no significant effect on latency to courtship,courtship intensity,mating duration,mating success rate,latency to egg laying,latency to egg hatching,but mixed food feeding Pardosa pseudoannulata can significantly increase the rate of egg hatching,increase the number of spiderlings while reduce the rate of egg cannibalism.