Gastrophysa viridula (Coleoptera: Chrysomelidae) in the Czech Republic: Decline in a once abundant invasive oligophagous consumer of Rumex

Zdeňka Martinková ,Pavel Saska,Alois Honěk

doi:10.14411/eje.2021.026

Abstract

While the progress of the spread of invasive species of insects in new geographical areas are usually intensively monitored, the decline of these species often escape attention and is poorly documented. In this study, we record the decline in abundance of Gastrophysa viridula (DeGeer), an invasive oligophagous consumer of dock (Rumex spp.). This species originally inhabited Alpine regions. In the late 1800s, G. viridula was recorded in montane areas in the Czech Republic and then throughout this country. Gastrophysa viridula was very abundant in 1995-1999, when we found it in all of the 177 stands of R. obtusifolius inspected in western Czech Republic. In a repeated study of its occurrence in the same area from 2019-2020, this species was present in < 30% of 434 of the stands inspected and was only abundant (≥ 55% of plants in the stand infested by G. viridula) in < 4% of these stands. Thus the local occurrence and abundance of G. viridula had decreased significantly. Of the possible reasons for this decline the most probable are the effect of climate warming on host plant seasonality, changes in agricultural use of grasslands and fragmentation of large stands of dock.

Highlights

Invasion, an encroachment of a species from one area into another (Lincoln et al, 1998), is an intensively studied ecological phenomenon
From 1995–1999 (Fig. 1), G. viridula occurred in all 177 local stands of R. obtusifolius visited
No relationship was found between the abundance of G. viridula and altitude of the localities of the dock stands (Fig. 3)

Summary

Introduction

An encroachment of a species from one area into another (Lincoln et al, 1998), is an intensively studied ecological phenomenon These species often have a marked effect on native ecosystems in newly colonized areas (Bradshaw et al, 2016) and sometimes negative economic consequences (Kenis et al, 2009). In Bohemia, this was well documented, and when first recorded in the mid-1800s, this species was very rare and present only in the highlands (Lokaj, 1869) Since it has spread throughout Central Europe (Franck, 1935) and by the 1950s, it was abundant in dock stands throughout the Czech Republic (Balthasar, 1957). Gastrophysa viridula is considered to be an important factor in the biological control of Rumex in pastures and managed grasslands (Bentley et al, 1980; Cottam et al, 1986; Grossrieder & Keary, 2004)

Methods

Results

Conclusion