| The Hessian fly,Mayetiola destructor(Say)(Diptera: Cecidomyiidae),is one of the most important quarantine pests in China.In recent years,there have been many outbreaks in Bortala Mongol Autonomous Prefecture,Xinjiang.Extreme weather events are increasing in frequency due to the warming climate.In order to know the effects of high temperature stress on the individual development and population dynamics of Hessian fly,this experiment compared the survival rate,sex ratio and development duration of Hessian fly at different life stages(eggs,first-instar larvae)after short-term high temperature at 31?,37? for 2 hours and 21? under constant temperature conditions.Meanwhile the activities of SOD,POD and CAT and the total antioxidant capacity(T-AOC)were determined after short-term high temperature(31,37? respectively,for 1,2 and 4 hours).The results show that:1.37? high temperature will reduce the survival rate of egg-adults,31? high temperature has no significant effect on survival rate;31? and 37? high temperature treatment in egg will accelerate the individual development,but it has a significant effect on males;The high temperature treatment at 31? and 37? will delay the development of the first-instar larva and have a significant effect on the female.2.Brief heat shock affect the development rate of Hessen fly.The developmental duration of females in the first-instar larval stage at 31? and 37? was significantly longer than that in the egg stage at 31? and 37?,and the development period of the female at 31? was significantly greater than that in the control;The developmental period of male worms was shortened after treatment at the egg stage of 31? and 37?,and the development period at 31? was significantly shorter than that of the control.But the magnitude of this effect is related to the sex.3.The high temperature treatment of 31? and 37? in egg and first-instar larva has no significant effect on the fertility after emergence into adults.4.The sex ratio of the Hessian fly is female-biased,and the brief heat shock has no significant effect on the sex ratio of the population.The sex ratio is 2.23: 1 under the constant temperature 21?.After the high temperature treatment at the egg stage 31?,37? and the larval stage 31?,37?,the female-male ratio is 2.32: 1,2.10: 1,1.51: 1 and 1.59: 1.5.The activity of antioxidant enzymes in Hessian fly is related to the developmental stage.The change of activity after high temperature stress is related to the development period and the duration of high temperature.The activity of SOD increased under high temperature stress in the first instar,and there was no significant change when treated at 31? for 1 hour and 2 hours in the second and third ages.The activity at 31? lasted for 4 hours and at 37? for different treatment times both decreased,and showed a trend of rising first and then decreasing with the prolongation of treatment time in the pupal stage.The activity of POD increased at 37? for 1hour in the first instar and 31? for 1 hour at the second instar,but there was no significant change in activity at other temperatures and time combinations in the first and second instars;31? at the third instar.There was no significant change in the activity of CAT enzyme at all developmental stages.The effects of high temperature in the first and second instars on T-AOC are not obvious.In the third instar,31? will inhibit the activity,but there is no significant change in the activity at 37?.The activity under the high temperature in the pupal stage is suppressed.As the temperature increases,it continues The longer the time,the more obvious the inhibitory effect of high temperature on its activity.In general,the extreme high temperature environment is not conducive to the survival of Hessian fly.Over 4 hours high temperature stress will inhibit the activity of antioxidant enzymes. |
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