Variation of larval size and adult emergence period of Boyeria irene (Fonscolombe, 1838) (Odonata: Aeshnidae) in the Francia River of western Spain

Patricia Casanueva,M Ángeles Hernández,Luisa Nunes,Luis Fernando Sánchez-Sastre,Francisco Campos

doi:10.1080/01650424.2021.1959037

Patricia Casanueva, M Ángeles Hernández + Show 3 more

Open Access

https://doi.org/10.1080/01650424.2021.1959037

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Abstract

Boyeria irene (Fonscolombe, 1838) is a large dragonfly common in rivers and streams in southern Europe, but it is little known about the biometrical variations of their populations. In this paper, we test whether the time of the emergence period of this species differs in the same river, whether the larval size varies during the emergence period, and whether the distinct size variations are associated with the different river sections. Results have revealed that 1) female exuviae are larger than those of males, 2) except for the paraproct length, the exuviae have similar size across the entire river length, 3) size of the exuviae is larger in the first period of emergence than in the second one. A difference in emergence duration across the three river sections has been recorded.

Highlights

Biometric comparisons allow us to know whether a species varies in size over wide geographic areas, as has been shown for various insect species (e.g., Hassall, Keat, Thompson, and Watts 2014; Horne, Hirst, and Atkinson 2015; Zeuss, Brunzel, and Brandl 2017; Casanueva et al 2020)
Several hypotheses have been proposed to explain variation in their body size; among them the temperature-size rule, TSR (Atkinson 1994), which proposes that the development rate increases with temperature, the body size of adult specimens may be smaller in warmer areas, as well as later in season
We present data on the adult emergence of B. irene in order to test whether, in the same river (Francia River, western Spain), its emergence period differs between zones and whether larval size varies during the emergence period and between zones

Summary

Introduction

Biometric comparisons allow us to know whether a species varies in size over wide geographic areas, as has been shown for various insect species (e.g., Hassall, Keat, Thompson, and Watts 2014; Horne, Hirst, and Atkinson 2015; Zeuss, Brunzel, and Brandl 2017; Casanueva et al 2020). Several hypotheses have been proposed to explain variation in their body size; among them the temperature-size rule, TSR (Atkinson 1994), which proposes that the development rate increases with temperature, the body size of adult specimens may be smaller in warmer areas, as well as later in season. This rule has been applied to both uni- and multicellular organisms (Atkinson, Morley, and Hughes 2006).

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