冷藏米蛾卵对稻螟赤眼蜂和玉米螟赤眼蜂子代质量的影响

Influence of cold-storage of Corcyra cephalonica eggs on the offspring quality of Trichogramma japonicum and Trichogramma ostriniae

【目的】以稻螟赤眼蜂Trichogramma japonicum Ashmead和玉米螟赤眼蜂T.ostriniae为试验对象,研究低温冷藏米蛾卵对赤眼蜂子代质量的影响,为米蛾卵的合理利用,赤眼蜂的工厂化生产和应用提供理论依据。【方法】将米蛾卵在不同温度(1、4、7、10℃)下冷藏不同时间(3、5、7、10、15、20、25、30、40d),研究米蛾卵冷藏后作为寄主卵对两种赤眼蜂子代寄生卵量、F_2代羽化出蜂率和雌蜂率的影响,利用赤眼蜂子代寄生卵量、F_2代羽化出蜂率和雌蜂率三者乘积表示赤眼蜂子代质量(Q),根据赤眼蜂子代质量判断冷藏米蛾卵对子代质量的影响。【结果】米蛾卵冷藏温度和时间对赤眼蜂子代寄生卵量影响显著,但不同赤眼蜂种类和不同冷藏温度间表现不同。繁殖稻螟赤眼蜂时,米蛾卵在4℃下冷藏赤眼蜂寄生卵量下降最缓,米蛾卵冷藏20d内赤眼蜂寄生卵量与对照之间差异不显著,在其他温度下米蛾卵冷藏3 d稻螟赤眼蜂寄生卵量与对照之间差异达到显著水平;繁殖玉米螟赤眼蜂时,米蛾卵在4℃下冷藏赤眼蜂寄生卵量下降最缓,米蛾卵冷藏20d赤眼蜂寄生卵量与对照之间差异达到显著水平,1℃下冷藏赤眼蜂寄生卵量下降最快,米蛾卵冷藏5 d赤眼蜂寄生卵量与对照之间达到显著水平。米蛾卵冷藏对稻螟赤眼蜂和玉米螟赤眼蜂F_2代的羽化率和雌蜂率产生的不利影响相对较小,米蛾卵冷藏30 d赤眼蜂F_2代的羽化率仍在70%以上,雌蜂率仍在75%以上。【结论】米蛾卵冷藏超过一定的时间以后会对稻螟赤眼蜂和玉米螟赤眼蜂子代的寄生卵量,F_2代的羽化出蜂率和雌蜂率产生不利影响,从而降低子代稻螟赤眼蜂和玉米螟赤眼蜂的质量,但在适宜的温度下冷藏一定时间内对其子代质量影响不显著,其中4℃下冷藏米蛾卵繁殖的赤眼蜂子代质量最佳,冷藏30 d赤眼蜂子代质量降低不到50%。

[Objectives]To investigate the effects of cold-storage of Corcyra cephalonica eggs on the offspring quality of Trichogramma japonicum and T.ostriniae.[Methods]C.cephalonica eggs were stored at 0,3,6 and 10℃for 0,3,5,7,10,15,20,25,30 and 40 days,and the effects of feeding eggs subject to these treatments on the parasitic capacity of Trichogramma sp.offspring,adult emergence rate and the proportion of females in the second generation were recorded and compared.The product of the number of parasitized eggs,emergence rate and proportion of females was used to evaluate the quality of Trichogramma offspring.[Results]Refrigerating C.cephalonica eggs had significant effects on the parasitizing capacity of T.japonicum and T.ostriniae offspring.The effect was least apparent when eggs were refrigerated at 4℃and eggs refrigerated at this temperature had the least effect on the oviposition rate.Eggs that had been refrigerated for 20 days had no clear effect on the oviposition rate.Oviposition of wasps raised on eggs refrigerated at 1℃decreased the fastest,eggs refrigerated for 3 days for T.japonicum and 5 days for T.ostriniae significantly reduced oviposition rates of both species.Clear differences were also observed in the emergence rate and proportion of females in the second generation,however,the emergence rate of wasps produced by eggs refrigerated for 30 days was still above 70%,and the proportion of females was still above 75%.[Conclusion]Refrigerating C.cephalonica eggs at a suitable temperature for a certain period of time had no significant effect on the quality of offspring produced by T.japonicum and T.ostriniae.The optimum temperature for refrigerating eggs was 4℃and the quality of Trichogramma sp.offspring was decreased by less than 50%by 30 days of refrigeration.