Phase polyphenism in locusts: factors inducing gregarization

荒漠蝗虫对种群密度或拥挤的响应表现出多相现象。在本研究中，我们研究了控制该蝗虫后代大小和颜色以及若虫体色和群居行为的因素，以了解其控制阶段多物性的机制。拥挤诱导这种蝗虫的身体颜色和行为的相依变化。我们发现，光是视觉刺激就能诱导绿色独居若虫形成黑色图案。我们还发现，短短1天的拥挤可以导致绿色独居的3龄若虫形成黑色图案。孤立的三龄若虫通常会避开其他个体，需要2天的拥挤才能开始被其他个体吸引。这些发现将为研究蝗虫多物性的遗传调控机制提供一个很好的检测系统。

The desert locust exhibits phase polyphenism in response to population density or crowding. In this study we examined the factors controlling progeny size and color as well as nymphal body color and gregarious behavior in this locust to understand the mechanism controlling the phase polyphenism. Crowding induces phase-dependent change in body color and behavior in this locust. We found that visual stimuli alone can induce green solitarious nymphs to develop black patterns. We also found that as short as 1 day of crowding can cause green solitarious 3rd instar nymphs to develop black patterns. Third instar isolated nymphs, which normally avoid other individuals, required 2 days of crowding to start being attracted to other individuals. These findings would provide an excellent assay system to examine the underlying genetic mechanism regulating the phase polyphenism in this locust.