寄主对瓜实蝇老熟幼虫和蛹的低温耐受性的影响

Effects of host plant on the low-temperature tolerance of fully-grown larvae and pupae of Bactrocera cucurbitae(Coquillett)

为明确不同寄主饲养的瓜实蝇Bactrocera cucurbitae(Coquillett)幼虫与蛹的低温耐受性差异,选择西葫芦Cucurbita pepo、节瓜Benincasa hispida和黄瓜Cucumis sativus饲养多代的瓜实蝇老熟幼虫和不同日龄的蛹,分别测定其过冷却点、结冰点和在不同低温下的存活率,并进行比较分析。结果表明:取食不同寄主植物的瓜实蝇老熟幼虫过冷却点无显著差异,取食节瓜的老熟幼虫的结冰点[(-5.33±0.23)℃]最低,且与取食黄瓜的种群没有显著差异;取食节瓜的蛹的过冷却点与结冰点均最低,其中1日龄、3日龄和5日龄蛹的过冷却点和结冰点分别为(-19.28±0.30)℃和(-15.06±0.34)℃,(-20.97±0.40)℃和(-17.33±0.39)℃,(-20.08±0.46)℃和(-16.39±0.46)℃。取食节瓜和黄瓜的老熟幼虫在3、6℃和9℃下暴露1 d,其存活率均显著高于取食西葫芦的老熟幼虫;节瓜种群的1日龄蛹在3℃和9℃下暴露1 d时,其存活率都显著高于黄瓜和西葫芦种群的1日龄蛹的存活率。寄主植物可影响瓜实蝇的过冷却点、结冰点及低温存活能力,与其他寄主种群相比,瓜实蝇节瓜种群老熟幼虫和蛹对低温的适应能力更强。

To clarify the differences in supercooling points and low-temperature survival ability of larvae and pupae of the melon fruit fly,Bactrocera cucurbitae(Coquillett),feeding on different host plants,the supercooling point,freezing point of mature larvae and pupae of B.cucurbitae reared for more than 10 generations on Cucurbita pepo,Benincasa hispida and Cucumis sativus were measured under indoor conditions,and their low-temperature survival rate was compared after exposed to 3,6℃or 9℃for different durations.There was no significant difference in supercooling points of the mature larvae feeding on different host plants.The freezing points of the mature larvae feeding on B.hispida was the lowest[(-5.33±0.23)℃],which was not significant different from those feeding on C.sativus.The supercooling points and freezing points of the pupae feeding on B.hispida was the lowest,and the supercooling points of 1-day-old,3-day-old and 5-day-old pupae were(-19.28±0.30)℃,(-20.97±0.40)℃and(-20.08±0.46)℃,respectively.The freezing points of 1-day-old,3-day-old and 5-day-old pupae feeding on B.hispida were(-15.06±0.34)℃,(-17.33±0.39)℃and(-16.39±0.46)℃,respectively.The survival rates of mature larvae feeding on B.hispida and C.sativus were significantly higher than those feeding on C.pepo when exposed to 3,6℃or 9℃for one day.When exposed to 3℃or 9℃for one day,the survival rates of 1-day old pupae of B.hispida population were significantly higher than those of C.sativus and C.pepo populations.The supercooling point,freezing point and low-temperature survival ability of B.cucurbitae can be affected by its host plants.The adaptabilities of the mature larvae and pupae of B.hispida population to low-temperature conditions were better compared to the other populations.