von Dohlen C D, Gill D E
Department of Zoology, University of Maryland, 20742, College Park, MD, USA.
Oecologia. 1989 Feb;78(2):165-175. doi: 10.1007/BF00377152.
Two divergent life cycles associated with different elevations and latitudes have been documented for the witch-hazel leaf gall aphid, Hormaphis hamamelidis. At low elevation in northern Virginia, the aphid had seven distinct generations alternating between the primary host, witchhazel (Hamamelis virginiana), and a secondary host, river birch (Betula nigra). These findings confirm the original published life cycle description for the same locality. A second, abbreviated life cycle consisting of only three generations restricted to witch-hazel was discovered at high elevation (1000 m) in north central and northwestern Virginia. Aphids of both life cycles were sympatric at a middle elevation site. The life cycles and morphology suggest that the two forms are separate species. Although monoecious life cycles on primary hosts in aphids generally are thought to be ancestral to complex host-alternating ones, it is certainly possible that monoecious cycles are sometimes secondarily derived from complex cycles. By constructing a preliminary phylogeny of the described species in the tribe Hormaphidini, we propose that the abbreviated life cycle is derived from the complex one in the case of these witchhazel gall aphids. Our findings are discussed in the context of current theory regarding the evolutionary stability of complex life cycles.
对于金缕梅叶瘿蚜（Hormaphis hamamelidis），已经记录到了与不同海拔和纬度相关的两种不同的生命周期。在弗吉尼亚州北部的低海拔地区，这种蚜虫有七代明显不同的世代，在主要寄主金缕梅（Hamamelis virginiana）和次要寄主河桦（Betula nigra）之间交替。这些发现证实了同一地区最初发表的生命周期描述。在弗吉尼亚州中北部和西北部的高海拔地区（1000米）发现了第二种仅由三代组成的简化生命周期，且仅限于金缕梅。两种生命周期的蚜虫在一个中等海拔的地点共存。生命周期和形态表明这两种形式是不同的物种。虽然一般认为蚜虫在主要寄主上的雌雄同体生命周期是复杂的寄主交替生命周期的祖先，但雌雄同体生命周期有时也可能是从复杂生命周期次生而来的。通过构建 Hormaphidini 族中所述物种的初步系统发育树，我们提出在这些金缕梅瘿蚜的情况下，简化生命周期是从复杂生命周期衍生而来的。我们的发现是在关于复杂生命周期进化稳定性的当前理论背景下进行讨论的。
