不同环境因子对桉树枝瘿姬小蜂生长适应性的影响

Adaptation of Leptocybe invase to Varying Environmental Conditions

【目的】研究环境因子对桉树枝瘿姬小蜂生长适应性的影响,旨在探究该害虫快速入侵及适应新环境的生理机制。【方法】测定不同地理区域的形态指标、不同温度下的形态指标、呼吸强度、保护酶(超氧化物歧化酶、过氧化氢酶、过氧化物酶)活性和取食不同寄主的形态指标、解毒酶(乙酰胆碱酯酶、羧酸酯酶、谷胱甘肽-S转移酶、多酚氧化酶)活性。【结果】桉树枝瘿姬小蜂的形态指标与纬度呈现负相关的趋势;温度对桉树枝瘿姬小蜂的呼吸强度和体内的保护酶活性均存在显著影响,20~30℃范围内,桉树枝瘿姬小蜂的呼吸速率和保护酶活性相对稳定,当超过30℃时,桉树枝瘿姬小蜂的呼吸速率显著上升,但是保护酶活性显著下降;当低于20℃时桉树枝瘿姬小蜂的呼吸速率显著下降,保护酶活性也显著下降。不同寄主对桉树枝瘿姬小蜂体内的解毒酶活性和形态指标也存在着显著的影响,取食巨园桉DH201-2的桉树枝瘿姬小蜂形态指标与4种解毒酶(乙酰胆碱酯酶、羧酸酯酶、谷胱甘肽-S转移酶、多酚氧化酶)的平均活性均高于取食窿缘桉的桉树枝瘿姬小蜂相应的指标。【结论】桉树枝瘿姬小蜂的形态大小与纬度呈现负相关的趋势,该害虫的适宜温区是20~30℃,取食巨园桉的形态指标和解毒酶活性均高于取食窿缘桉的。

【Objective】Adaptability to environmental variations of Leptocybe invase Fisher et LaSalle for growth and survival was investigated based on the physiological mechanisms of the pest in dealing with the adverse conditions.【Methods】Geography-,temperature-,and host-specific morphological indicators,respiratory intensity,and activities of protective enzymes(such as,superoxide dismutase,catalase,peroxidase)and detoxification enzymes(such as,acetylcholinesterase,carboxylesterase,glutathione-S-transferase,polyphenol oxidase)of the insect were analyzed.【Results】The morphological indicators of L.invase were inversely correlated to the latitude of the area it lived in.Its respiratory intensity and protective enzyme activity were relatively stable between 20℃and 30℃.However,a surrounding temperature beyond 30℃significantly raised the respiration rate and reduced the protective enzyme activity,while below 20℃significantly decreased both.The diet also induced morphological differentiations in the insect.For instance,and the activities of 4 detoxification enzymes(acetylcholinesterase,carboxylesterase,glutathione-S-transferase,and polyphenol oxidase)were higher in the insects fed on DH201-2(Eucalyptus grandis×E.tereticornis)than those on E.exserta.【Conclusion】L.invase found in areas of lower latitude were smaller in body size than those of higher latitude.They thrived between 20℃and 30℃.And the host plants on which they infested affected their morphology as well as the detoxification enzymes in the insect.