Does wing dimorphism affect mobility in Metrioptera roeselii (Orthoptera: Tettigoniidae)?

Dominik Poniatowski,Thomas Fartmann

doi:10.14411/eje.2011.052

Abstract

Range shifts are among the most conspicuous effects of global warming. Marked changes in distribution are recorded both for highly mobile species of insects, which are capable of flight, and wing-dimorphic species with predominantly short-winged individuals. One of these species is the bush-cricket Metrioptera roeselii, which occasionally produces long-winged individuals. However, there is little known about the locomotory behaviour of wing-dimorphic insects. Yet to be able to predict potential range shifts it is necessary to know the dispersal potential of macropters. Therefore, an experiment was conducted in which individually marked M. roeselii were released at four sites. Different movement parameters, such as daily movement, activity radius, dispersal range, net displacement and crowding rate, were calculated. The statistical analyses showed that the movement of long-winged and short-winged individuals did not differ, but the percentage of individuals that were not seen again was twice as high for long-winged bush-crickets. These results suggest that most of the long-winged individuals that were seen again did not fly; i.e., they had the same basic mobility as the short-winged individuals. However, the comparatively low number of long-winged individuals that were seen again suggests that at least some macropters are long-distance dispersers, which is relevant for the dispersal process. The comparison of sexes showed that males were significantly more mobile than females. This sex-specific locomotory behaviour in M. roeselii might depend on a complex series of social interactions and physiological conditions.

Highlights

Global warming is likely to have highly diverse effects on species
Range shifts are frequently recorded for taxa with intermediate dispersal abilities, such as most butterflies (Parmesan et al, 1999) and even insect groups with many flightless species, like Orthoptera (Reinhardt et al, 2005)
This study focuses on the latter dispersal strategy

Summary

Introduction

Global warming is likely to have highly diverse effects on species. Range shift is one example. Range shifts are frequently recorded for taxa with intermediate dispersal abilities, such as most butterflies (Parmesan et al, 1999) and even insect groups with many flightless species, like Orthoptera (Reinhardt et al, 2005). In addition to species with passive dispersal (Fartmann, 2004) there are species that have a high flight ability (Kleukers et al, 1996; Koþárek et al, 2008) or a well developed wing dimorphism (Simmons & Thomas, 2004; Hochkirch & Damerau, 2009). Until the mid-20th century, macropters of wing-dimorphic Orthoptera were rarely recorded in Europe (Ramme, 1931). Many researchers assign macropters an important role in dispersal (Simmons & Thomas, 2004; Gardiner 2009; Hochkirch & Damerau, 2009)

Methods

Results

Conclusion