蚜虫翅型分化的影响因素及其发生机制

翅多型现象在昆虫中广泛存在,比如蚜虫有有翅蚜和无翅蚜,无翅蚜无翅不能飞行。翅型分化是蚜虫对不良生态环境的适应策略。有翅蚜能飞行,使其逃离不良环境并找到新的栖息地;而无翅蚜繁殖周期短、繁殖量大,有助于维持一定的种群数量。影响蚜虫翅发育的因素有遗传因素和环境因素,由环境因素决定的翅的多型现象被称为翅的非遗传多型性。本文就蚜虫翅型分化的生态学意义、影响因素,以及蚜虫翅型分化的生理和分子机制进行了综述。关于影响蚜虫翅型分化的遗传因素的研究较少,部分研究发现豌豆蚜翅型由X染色体上的一对等位基因所控制。更多的研究表明蚜虫翅型分化受环境因素影响,影响蚜虫翅型分化的环境因素有光周期、温度、种群密度、共生微生物、天敌、杀虫剂及抗生素等,事实上这些环境因素往往不是单方面存在的。保幼激素、蜕皮激素等外源激素会影响包括蚜虫在内昆虫的翅型分化,蚜虫的拥挤效应最终可能也是通过激素调控发挥作用。外源激素可以作用于出生后的低龄若虫也可作用于预产期的成虫,比如给豆蚜中龄若蚜施加保幼激素处理后,会出现超龄若虫,而不是无翅蚜。相反,反-β-法尼烯（EBF）的刺激会诱导有翅蚜后代的产生。另有研究发现,上一代豌豆蚜注射蜕皮激素可以减少有翅后代数量,而通过RNA干扰（RNA interference, RNAi）EcR受体或施加EcR抑制物也会导致后代有翅个体增加。蚜虫翅型分化分子机制的研究起始于对同一基因型蚜虫有翅、无翅成虫个体的差异表达基因或差异表达蛋白。

The Influencing Factors and Mechanism of Wing Dimorphism in Aphid

Wing polymorphism is commonly observed in insects, for the sake of example, there are winged morph and wingless morph in aphids, the wingless morph lacks wings and is called apterous morph. Be of wings, the alate aphids can fly, successfully escape from wicked environment and find new habitat. Besides, the short reproduction cycle and large reproduction of apterous aphid are helpful to maintain a certain population. For aphid, wing dimorphism is an adaptive strategy in response to wicked environment. Both genetic and environmental factors are usually considered to affect the developmental outcomes of insect wing morphs. The wing polymorphism mainly affected by environment is called polyphenism. In this review, the ecological adaptive significance, influencing factors on determination of wing form, physiological and molecular mechanism of wing polymorphism were summarized. There are a few researches about wing dimorphism of Aphid, which partially confirmed that the wing type of pea aphid is controlled by an allele on the X chromosome. More researches identified that the environmental factors, including photoperiod, temperature, population density, symbiotic microorganisms, natural enemy, pesticides and antibiotics, may play an important role in this dimorphism. But in fact, these environmental factors often do not exist unilaterally. Juvenile hormone, ecdysone and other exogenous hormones are believed have interference effect on wing dimorphism. The appearance of crowding effect is probably resulted from the role of exogenous hormones.These factors may act prenatally, postnatally or both, depending on the species. For example, the middle instar nymphs treated by juvenile hormone probably develop to be supernumerary larva, not to be wingless adults. On the contrary, (E)-β-farnesene induced more winged morph offspring. Previous experimental injections of ecdysone or its analog resulted in a decreased production of winged offspring of Acyrthosiphon pisum. Furthermore, interfering with ecdysone signaling using an ecdysone receptor antagonist or knocking down the ecdysone receptor gene with RNAi resulted in an increased production of winged offspring. Molecular mechanism of wing type differentiation of aphids starts from the expressed differential genes or proteins of winged and wingless aphid of the same genotype.