Phenology and interspecific association of Forficula auricularia and Forficula pubescens in apple orchards

Jaume Lordan,Rob Moerkens,María-José Sarasúa,Simó Alegre,Georgina Alins

doi:10.5424/sjar/2015131-6814

Abstract

The European earwig Forficula auricularia L. (Dermaptera: Forficulidae) has been widely studied as a key predator of pests in temperate regions, but its phenology and behavior may differ in warmer areas such as the Mediterranean. Here we assessed the phenology, aggregation, and interspecific association of F. auricularia and Forficula pubescens Gené, the only two species found consistently in both ground and canopy shelters in Mediterranean apple orchards. In addition to F. auricularia and F. pubescens, three other earwig species, namely Labidura riparia Pallas, Nala lividipes Dufour and Euborellia moesta Gené, were found occasionally. The mature stages of F. auricularia were observed mainly from May to November in tree shelters and immature ones from October to June in ground shelters. Adult individuals of F. pubescens were observed year-round and nymph instars were detected from April to June in ground as well as in tree shelters. The suitability of the current degree-days models for temperate regions was evaluated for the prediction of European earwig phenology in a Mediterranean climate. Regarding interspecific association, F. auricularia and F. pubescens co-occurred in canopies without apparent competition. This study provides useful weekly data about the phenology of the two earwig species throughout the year that can be used to detect the key periods during which to enhance their populations in pip fruit orchards or to control them in stone fruit crops. Furthermore, our results are of relevance for the development of new phenological models of earwigs in Mediterranean areas where nymphs hibernate, a feature that makes current models inaccurate.

Highlights

The role of the European earwig, Forficula auricularia Linnaeus (Dermaptera: Forficulidae), as a generalist predator in orchards has been widely cited
This study provides useful weekly data about the phenology of the two earwig species throughout the year that can be used to detect the key periods during which to enhance their populations in pip fruit orchards or to control them in stone fruit crops
We evaluated the suitability of the current degree-days models for temperate regions to predict the phenology of the European earwig in a Mediterranean climate

Summary

Introduction

The role of the European earwig, Forficula auricularia Linnaeus (Dermaptera: Forficulidae), as a generalist predator in orchards has been widely cited. Due to their omnivorous diet, European earwigs can cause economic damage to stone fruit crops (Albouy & Caussanel, 1990; Kuthe, 1996; GraftonCardwell et al, 2003; Huth et al, 2011). To control earwigs in conventional fruit production, growers spray orchards with commonly used pesticides such as chlorpyrifos and spinosad (Hetherington, 2006; Peusens & Gobin, 2008; Vogt et al, 2010; Fountain et al, 2013). Alternative strategies, such as mass trapping and exclusion by setting glue around the base of tree trunks, are used (Hetherington, 2006; Alston & Tebeau, 2011; Saladini et al, 2012)

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