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

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. Additional key words: biological control; Dermaptera; earwig; Forficulidae; Mediterranean; pest

Lifecycle of the invasive omnivore, Forficula auricularia, in Australian grain growing environments

“…Lower soil temperatures in those regions with cold winters prohibits the development of F. auricularia eggs, 27 whereas at our field sites, eggs are able to develop consistently following oviposition. Perhaps this is why our findings are similar to those observed in Southern Europe, 37‐39 where winter temperatures are most analogous to Australia.…”

“…We compared the seasonal timing of F. auricularia life stages found in this study with patterns recorded in the northern hemisphere, specifically those from North America and Europe. 26,27,29,[35][36][37][38][39][40] After adjusting for the 6 month seasonal differences between the northern and southern hemispheres, we find the lifecycle of F. auricularia is completed much earlier in our Australian regions than the northern hemisphere, despite similar dates for egg-lay (Table 5). First instars hatching from eggs appeared early in winter, almost 6 months earlier than in the northern hemisphere.…”

“…There are four nymphal stages of development, called instars. 4 The lifecycle of F. auricularia has been examined in cool and temperate regions in the Northern hemisphere, [28][29][30][31][32][33][34][35][36][37][38][39][40] with information recently garnered from Australian orchard environments 41,42 and New Zealand. 20,43 Oviposition occurs within subterranean nests excavated by the female, in the northern hemisphere, this typically occurs from late summer to spring depending on the region.…”

Temporal activity of spiders and earwigs during winter in apple trees under a Mediterranean climate

“…more than 25% of the catches in winter) whereas the other (F. auricularia) had none. These observations of the marked difference between these two species are in agreement with those made by Lordan, Alegre, Moerkens, Sarasua, and Alins (2015) in Spanish apple orchards. The implications of this finding are not easy to determine since F. pubescens is known to have a more diversified feeding regime (Romeu-Dalmau, Espadaler, & Pinol, 2011).…”

The Contribution of Surrounding Margins in the Promotion of Natural Enemies in Mediterranean Apple Orchards

“…In this case, A. mali was the main beneficial arthropod found in the colonies, while the presence of predators was anecdotal. Even though earwigs, which are one of the most important WAA predators [15,48,49], are present in our study area [50], we failed to find them because our sampling method was not appropriated to assess this predator. Earwigs feed at night and remain concealed during the day [51], so night visual samplings would be required to detect the predatory activity of this insect on WAA colonies.…”