Molecular systematics and evolution of the aphid family Lachnidae.

The aphid family Lachnidae (c. 320 spp.)-sister-group to the economically devastating family Aphididae (c. 3300 spp.)-encompasses a diverse array of associations with hostplants and attendant hymenopterans and of life histories, including potentially long-term parthenogenesis. Most-parsimonious phylogenetic trees were inferred from partial (905-coding-bp) sequences of elongation factor 1alpha (EF-1alpha) and complete (675-bp) sequences of cytochrome oxidase 2 (CO2). The EF-1alpha, CO2, and combined analyses did not conflict with each other. Most tribes and infratribal relationships were robustly supported; intertribal relationships were mostly unresolved in the separate analysis and only weakly supported in the combined analysis. Both genes indicated a close relationship between the genera Nippolachnus and Tuberolachnus, both of which include species with the unusual habit of feeding along the midrib of leaves of Eriobotrya and which are here referred to the tribe Tuberolachnini Mamontova. A sister-group relationship between Tuberolachnini and the putatively ancient asexual tribe Tramini is supported. The combined analysis provides support (albeit weak) for the hypothesis that conifer-feeding is ancestral in Lachninae, which in turn implies that conifer-feeding may be a homologous and uninterrupted habit across disparate families of aphidoids (e.g., Adelgidae, Mindaridae, Drepanosiphidae, and Lachnidae). Copyright 2000 Academic Press.