Adaptive significance of precocious pupation in the bean blister beetle, Epicauta gorhami (Coleoptera: Meloidae), a hypermetamorphic insect
Adaptive significance of precocious pupation in the bean blister beetle, Epicauta gorhami (Coleoptera: Meloidae), a hypermetamorphic insect
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DOI：
10.1016/j.jinsphys.2017.03.011
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发表时间：
2017-05-01
影响因子：
2.2
通讯作者：
Tanaka, Seiji
中科院分区：
文献类型：
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作者：
Shintani, Yoshinori;Terao, Misato;Tanaka, Seiji
豆角豆蠹Epicauta gorhami Marvel（鞘翅目：根结线虫科）的幼虫以土壤中的蝗虫卵为食，并经历超变态。它们通常在五龄时进入滞育作为假蛹，这是一种象甲超变态的特征。然而，暴露于长日照和高温的四龄幼虫避免了假蛹滞育，直接从四龄开始化蛹。四龄幼虫也往往化蛹早熟与较小的身体大小，如果他们被剥夺了食物。在这些幼虫中，控制假蛹滞育诱导的临界日长变得短于饱食幼虫。在这项研究中，我们探讨了如何反应规范的食物剥夺E。在自然界中，gorhami幼虫的功能是在不同的季节在室外从卵期开始饲养昆虫，并控制食物供应。结果表明，大多数饱食的幼虫进入假蛹滞育，而缺乏食物的幼虫往往化蛹早熟，而不进入滞育，特别是在赛季初。由此产生的较小的成年人在秋季初繁殖，他们的后代达到pseudopupal冬季前的阶段，表明反应规范可能有一个适应性的作用，在控制季节性发展，面对食物短缺，生产二化性生命周期。
Larvae of the bean blister beetle, Epicauta gorhami Marseul (Coleoptera: Meloidae), feed on grasshopper eggs in soil and undergo hypermetamorphosis. They normally enter diapause as a pseudopupa at the fifth instar, a form characteristic of hypermetamorphosis for meloid beetles. However, fourth-instar larvae exposed to long days and high temperature avoid pseudopupal diapause and pupate directly from the fourth instar. Fourth-instar larvae also tend to pupate precociously with a smaller body size if they are deprived of food. In these larvae, the critical day-length controlling induction of pseudopupal diapause becomes shorter than that for fully-fed larvae. In this study, we examined how the reaction norm of food-deprived E. gorhami larvae functions in nature by rearing insects from the egg stage outdoors in different seasons with manipulation of the food supply. The results indicated that most fully-fed larvae entered pseudopupal diapause, whereas food-deprived larvae tended to pupate precociously without entering diapause, especially early in the season. The resulting smaller adults reproduced early in the autumn and their progeny attained the pseudopupal stage before winter, indicating that the reaction norm may have an adaptive role in controlling seasonal development in the face of food shortages, producing a bivoltine life cycle.