Cuticular hydrocarbon profiles as a taxonomic tool: Advantages, limitations and technical aspects

Abstract

Cuticular hydrocarbons (CHCs) are expressed on an insect's cuticle and are one of the major factors allowing insects to identify members of their own species, colony and gender. As a result of their species-specificity, CHCs are increasingly used to delimit species in addition to more conventional methods, such as morphology or genetic markers, and so play an important role in chemotaxonomy. Species vary in the type of CHCs that they produce, as well as in the relative quantities of shared compounds. This review summarizes not only how taxonomists may differentiate between species based on CHC profiles, but also the incentive for using CHC composition as taxonomic tool. Benefits regarding the identification of cryptic species and early signs of reproductive isolation are then discussed, giving examples from studies of taxonomy, behaviour and biosynthesis. For taxonomic characters to reliably indicate species boundaries, their limitations need to be known. Potential problems caused by environmental effects, intra-species variation in profiles and other technical issues are highlighted, and suggestions are made regarding their avoidance. It remains a challenge to determine the variation beyond which two species can be called independent; a problem shared by most methods of delimitation. Recently, there has been a shift towards using a combination of different taxonomic tools, both molecular and non-molecular, to test observed species differences. © 2012 The Authors. Physiological Entomology © 2012 The Royal Entomological Society.