Patterns of morphometric variation among species of the genus Cicada (Hemiptera: Cicadidae) in the Mediterranean area

Paula Cristina Simões,José Alberto Quartau

doi:10.14411/eje.2009.050

Abstract

Selected populations of five closely related species of the genus Cicada L. were collected mainly on the Portuguese, Greek and Turkish mainland, as well as on several Aegean islands. Ten morphometric traits of external structures and seven of male genitalia were analysed and the results revealed patterns in morphometric variation for each species. Only C. lodosi was always completely discriminated by both character sets and C. barbara by the male genitalia analysis. For the remaining species there was great overlap between the clusters. Body length, of the external morphological structures, and measurements of the pygophore, of the male genitalia, were the best variables for identifying C. lodosi and C. barbara. The present morphometric analyses revealed that divergence in morphology is much less pronounced than the divergence in acoustic signals and DNA. Thus, the congruence between morphological divergence, namely at the level of the external structures, and both behavioural (acoustic) and genetic divergence is quite low.

Highlights

Cicadas are Hemipteran insects usually recognised by the ability of males to produce loud airborne acoustic signals during pairing and courtship (e.g. Claridge, 1985; Boulard & Mondon, 1995; Quartau, 1995)
In many instances, like in the genus Cicada Linnaeus, where the male calls of the different species are quite distinct, it is difficult to separate specimens only on the basis of their morphology. These cicadas form a complex of sibling species looking very similar on the basis of the external morphology and even the male genitalia
Specimens collected from populations of five species on the mainland as well as several islands were analysed (C. barbara, C. cretensis, C. lodosi, C. mordoganensis and C. orni) (Fig. 1; Table 1)

Summary

Introduction

Cicadas are Hemipteran insects usually recognised by the ability of males to produce loud airborne acoustic signals during pairing and courtship (e.g. Claridge, 1985; Boulard & Mondon, 1995; Quartau, 1995). Females are only attracted to the calls of conspecific males, cicada acoustic signals are species specific (e.g. Claridge, 1985) and can be used, like taxonomic characters, to identify most species of cicada. In many instances, like in the genus Cicada Linnaeus, where the male calls of the different species are quite distinct, it is difficult to separate specimens only on the basis of their morphology. These cicadas form a complex of sibling species looking very similar on the basis of the external morphology and even the male genitalia. A few differences in structure and colour can be found, especially when large series of specimens are analysed (Quartau, 1988; Simões et al, 2000; Quartau & Simões, 2006)

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