| Atmospheric CO2 concentration was increased because of human activity since the industrial revolution year by year. And it was estimated that the atmospheric CO2 concentration would rise to 600-1000 ppm by 2100. Elevated CO2 concentration is thought to be the main reason for global climate change and the greenhouse effect. Because of the increasing atmospheric CO2 concentration, studying its effects on organisms has been a very popular subject in ecological research. Studies to date have mostly investigated the influence of elevated CO2 on plants, phytophagous insects, and natural enemy insects (predators and parasitoids). However, it remains unclear how an elevated CO2 concentration impacts spiders, a key predator of insects.The effects of elevated atmospheric CO2 on the growth, development and reproduction of the spiders (Araneae) were investigated by using Pardosa astrigena and Agelena labyrinthica as research objects. The contents of protein, total amino acid and free fatty acid of the spiders reared under different CO2 concentration were measured. Meanwhile, the activities of enzymes including peroxidase, amylase and superoxide dismutase from the spiders under different CO2 concentration were also determined. This study will rich and perfect the effects of elevated CO2 concentration on the organisms and responses of them. It will help us know more about harmful effects of the elevated CO2 concentration on human being. Our studies will deepen the understanding negative effects of elevated CO2 concentration on human. And it would contribute to the better protection and utilization of the spiders. The results are as follows:1. Impact of elevated CO2 on the growth, development of spiders and fecundity of the spiders, set up 370 ppm (control group) and 750 ppm (experimental group) CO2 concentration using carbon dioxide artificial climate box.2nd P. astrigera and A. labyrinthica were put in the artificial climate box. Developmental duration, length and width of carapace and weight of spiders were measured. Survival time of 2nd P. astrigera were observed to compare their resistances in no water and food. When spiders maturity to do the time of copulation, mating time, oviposition rate, number of egg sacs, total number of eggs and hatching rate of the spiders under two different CO2 concentrations. The results showed that total development duration of P. astrigera and A. labyrinthica were significance decrease under high CO2 concentration (t-test, P<0.05). And Length and width of carapace and weight of P. astrigera were significance decrease under different CO2 concentrations (t-test, P<0.05) while Length and width of carapace and weight of A. labyrinthica have no significance difference under different CO2 concentrations (t-test, P>0.05). Resistances of 2nd P. astrigera to hunger and dry were no significance difference under high CO2 concentration (t-test, P>0.05). And time of copulation, mating time, oviposition rate and hatching rate of P. astrigera have no significance difference under different CO2 concentrations (t-test, P>0.05). But number of egg sacs (t-test, t= 2.69, df= 9, P=0.025) and total number of eggs (t-test, t=3.49,df=14, P= 0.0036) of P. astrigera were significance decrease under high CO2 concentration.2. Impact of elevated CO2 on nutrient contents of the spiders, P. astrigera and A. labyrinthica. Spiders of 4th P. astrigera and 7 th A labyrinthica were randomly selected from 370 ppm (control group) and 750 ppm (experimental group) CO2 concentration to compare their protein contents, total amino acid contents and free fatty acid contents. Kits were used to measure them. The results showed that protein contents and total amino acid contents of two kinds of spiders have no significance difference under different CO2 concentrations (t-test, P>0.05). And free fatty acid contents of P. astrigera have no significance difference under high CO2 concentration (t-test, P>0.05), while free fatty acid contents of A. labyrinthica were significance decrease under different CO2 concentrations (t-test, t=7.49, df=4, P=0.02).3. Impact of elevated CO2 on enzyme activities of the spider, P. astrigera and A. labyrinthica. Spiders of 4th P. astrigera and 7th A.labyrinthica were randomly selected from 370 ppm (control group) and 750 ppm (experimental group) under different CO2 concentrations to compare their peroxidase activities, amylase activities and superoxide dismutase activities. Kits were used to measure them. The results showed that peroxidase activities and superoxide dismutase activities of two kinds of spiders have no significance difference under different CO2 concentrations (t-test, P>0.05). And amylase activities of spiders were significance improved under high CO2 concentration (t-test, P<0.05). |
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