Phylogeny of Insect Orders

TLDR: This review is devoted to a treatment of the phylogeny of extant orders of insects and their closest relatives and to the numerous new proposals made in a thought-provoking, recent book by Boudreaux (15).

Abstract: Phylogeny is evolutionary interrelationship expressed in terms of recency of common ancestry. The elaboration of the theoretical framework of phylogenetic systematics ("cladistics") by the Hennig school [(e.g. 34, 35); for an introduction to later developments see (5)] has led to an upsurge of interest in reconstruction of phylogenies and has proved particularly stimu­ lating for inquiries into concepts of interrelationships of higher categories. This review is devoted to a treatment of the phylogeny of extant orders of insects and their closest relatives. Palaeozoic hexapods are reviewed by Wootton in this volume. The "ordinal" level has been fixed largely by convention within each major group in the Animal Kingdom. The orders recognized here are presented in Figure 1. These taxa are obviously not equivalent by any criteria, but at least it can be argued that they are all monophyletic entities. A comprehensive treatise on the phylogeny of higher hexapod categories, including lengthy discussions of previous hypotheses, was published in 1969 by Hennig (35). Hennig's views were subsequently critically assessed by Kristensen (43) with reference to a substantial amount of additional evi­ dence. These two works provide extensive bibliographies and are referred to repeatedly throughout this review. Emphasis is laid on a presentation of current views, and particular consideration is given to the numerous new proposals made in a thought-provoking, recent book by Boudreaux (15).