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Evolutionary Ecology of Odonata: A Complex Life Cycle Perspective
Robby Stoks1,∗ and Alex Cordoba-Aguilar2 ´
1 Laboratory of Aquatic Ecology and Evolutionary Biology, University ofLeuven, B-3000 Leuven, Belgium; email: robby.stoks@bio.kuleuven.be 2

Annu. Rev. Entomol. 2012.57:249-265. Downloaded from www.annualreviews.org by Universidad Nacional Autonoma de Mexico on 03/05/12. For personal use only.

Departamento de Ecolog´a Evolutiva, Instituto de Ecolog´a, Universidad Nacional Autonoma ı ı ´ de M´ xico, 04510 DF, Mexico; email: acordoba@ecologia.unam.mx e

Annu. Rev.Entomol. 2012. 57:249–65 First published online as a Review in Advance on September 9, 2011 The Annual Review of Entomology is online at ento.annualreviews.org This article’s doi: 10.1146/annurev-ento-120710-100557 Copyright c 2012 by Annual Reviews. All rights reserved 0066-4170/12/0107-0249$20.00
∗

Keywords
carry-over effects, complex life cycle, decoupling mechanisms, maternal effects, fitnesscomponents, sublethal stress effects

Abstract
Most insects have a complex life cycle with ecologically different larval and adult stages. We present an ontogenetic perspective to analyze and summarize the complex life cycle of Odonata within an evolutionary ecology framework. Morphological, physiological, and behavioral pathways that generate carry-over effects across the aquatic egg andlarval stages and the terrestrial adult stage are identified. We also highlight several mechanisms that can decouple life stages including compensatory mechanisms at the larval and adult stages, stressful and stochastic events during metamorphosis, and stressful environmental conditions at the adult stage that may overrule effects of environmental conditions in the preceding stage. We consider theimplications of these findings for the evolution, selection, and fitness of odonates; underline the role of the identified numerical and carry-over effects in shaping population and metapopulation dynamics and the community structure across habitat boundaries; and discuss implications for applied conservation issues.

Corresponding author

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INTRODUCTION
Complex life cycle (CLC): a life cyclethat includes an abrupt ontogenetic change in ecology and morphology, often between larval and adult stages Hemimetabolous: describes a life cycle in which larvae resemble adults except for their small size and lack of wings and genitalia

Annu. Rev. Entomol. 2012.57:249-265. Downloaded from www.annualreviews.org by Universidad Nacional Autonoma de Mexico on 03/05/12. For personal use only.More than 80% of animals, including most insects, have a so-called complex life cycle (CLC) with discrete larval and adult stages (112). This is in contrast to animals with a simple life cycle, such as birds and mammals, that gradually turn into adults. The general adaptive explanation for the existence of CLCs, i.e., the adaptive decoupling hypothesis, states that CLCs and the associatedevolutionary origin of metamorphosis reflect selection for decoupling traits across life stages (66). It is still unclear to what extent life stages are decoupled, and it has even been argued that metamorphosis is not a new beginning (73) and that the prominence of CLCs may reflect difficulties in losing larvae from life cycles more than selection for their retention (72). The latter studies were based onreviews of the literature on marine invertebrates; so far no overview has been done in an insect order. In hemimetabolous insects a major transition occurs at metamorphosis, where a larval stage specialized for growth is followed by a metamorphosis to an adult stage specialized for dispersal and reproduction (113). These specialized functions together with the associated differences in habitat use,...