ANRV297-EN52-16 ARI 21 November 2006 10:26 Biology and Evolution of Adelgidae Nathan P. Havill1 and Robert G. Foottit2 1Department of Ecology and Evolutionary Biology, Yale University, New Haven, Connecticut 06520; email:
[email protected] 2Agriculture and Agri-Food Canada, Eastern Cereal and Oilseeds Research Centre, Ottawa, ON K1A 0C6, Canada; email:
[email protected] Annu. Rev. Entomol. 2007. 52:325–49 Key Words The Annual Review of Entomology is online at Aphidoidea, complex life cycle, cyclical parthenogenesis, ento.annualreviews.org plant-insect interactions This article’s doi: 10.1146/annurev.ento.52.110405.091303 Abstract Copyright c 2007 by Annual Reviews. The Adelgidae form a small clade of insects within the Aphidoidea All rights reserved (Hemiptera) that includes some of the most destructive introduced by Agriculture & Agri-Food Canada on 09/05/08. For personal use only. 0066-4170/07/0107-0325$20.00 pest species threatening North American forest ecosystems. De- spite their importance, little is known about their evolutionary his- Annu. Rev. Entomol. 2007.52:325-349. Downloaded from arjournals.annualreviews.org tory and their taxonomy remains unresolved. Adelgids are cyclically parthenogenetic and exhibit multigeneration complex life cycles. They can be holocyclic, with a sexual generation and host alterna- tion, or anholocyclic, entirely asexual and without host alternation. We discuss adelgid behavior and ecology, emphasizing plant-insect interactions, and we explore ways that the biogeographic history of their host plants may have affected adelgid phylogeny and evolution of adelgid life cycles. Finally, we highlight several areas in which ad- ditional research into speciation, population genetics, multitrophic interactions, and life-history evolution would improve our under- standing of adelgid biology and evolution.