Niitsu Shuhei, Sugawara Hirotaka, Hayashi Fumio
Department of Biology, Tokyo Metropolitan University, Minami-osawa 1-1, Hachioji, Tokyo, 192-0397, Japan.
Evol Dev. 2017 Jan;19(1):9-16. doi: 10.1111/ede.12213. Epub 2016 Nov 21.
The evolution of winglessness in insects has been typically interpreted as a consequence of developmental and other adaptations to various environments that are secondarily derived from a winged morph. Several species of bagworm moths (Insecta: Lepidoptera, Psychidae) exhibit a case-dwelling larval life style along with one of the most extreme cases of sexual dimorphism: wingless female adults. While the developmental process that led to these wingless females is well known, the origins and evolutionary transitions are not yet understood. To examine the evolutionary patterns of wing reduction in bagworm females, we reconstruct the molecular phylogeny of over 30 Asian species based on both mitochondrial (cytochrome c oxidase subunit I) and nuclear (28S rRNA) DNA sequences. Under a parsimonious assumption, the molecular phylogeny implies that: (i) the evolutionary wing reduction towards wingless females consisted of two steps: (Step I) from functional wings to vestigial wings (nonfunctional) and (Step II) from vestigial wings to the most specialized vermiform adults (lacking wings and legs); and (ii) vermiform morphs evolved independently at least twice. Based on the results of our study, we suggest that the evolutionary changes in the developmental system are essential for the establishment of different wingless forms in insects.
昆虫无翅的进化通常被解释为是从有翅形态次生而来的、对各种环境的发育和其他适应性的结果。蓑蛾的几个物种（昆虫纲：鳞翅目，蓑蛾科）表现出一种栖于袋中的幼虫生活方式，以及最极端的两性异形情况之一：无翅的成年雌性。虽然导致这些无翅雌性的发育过程是众所周知的，但其起源和进化转变仍不为人所知。为了研究蓑蛾雌性翅膀退化的进化模式，我们基于线粒体（细胞色素c氧化酶亚基I）和核（28S rRNA）DNA序列重建了30多种亚洲物种的分子系统发育。在简约假设下，分子系统发育表明：（i）向无翅雌性进化的翅膀退化由两个步骤组成：（步骤I）从功能性翅膀到残翅（无功能），以及（步骤II）从残翅到最特化的蠕虫状成虫（无翅无腿）；（ii）蠕虫状形态至少独立进化了两次。基于我们的研究结果，我们认为发育系统的进化变化对于昆虫中不同无翅形态的形成至关重要。
