Winter feeding leads to a shifted phenology in the browntail moth Euproctis chrysorrhoea on the evergreen strawberry tree Arbutus unedo

Abstract

1 The browntail moth Euproctis chrysorrhoea is a highly polyphagous univoltine forest pest. Although its young larvae usually overwinter in diapause from early autumn to the beginning of spring, winter larval feeding has been reported when this species feeds on the evergreen woody shrub strawberry tree Arbutus unedo. 2 The present study investigated life-history traits of four populations of E. chrysorrhoea feeding on A. unedo, including phenology of the different life stages, larval feeding activity and diapause incidence. By modelling the relationship between larval size and host plant leaf persistence, elevation and mean annual temperature, we also studied larval development in ten populations of this species sampled from a range of geographical locations in Spain, from both A. unedo and deciduous hosts. 3 The results obtained revealed that on A. unedo, E. chrysorrhoea phenology has shifted: from October to March, A. unedo larvae doubled their size, whereas, on deciduous Ulmus minor and Quercus faginea, larval size did not change. General linear models demonstrated that such differences were not related to environmental variables. We also found that on A. unedo larval feeding was arrested for 2 months, with this period representing a true diapause. 4 The results obtained in the present study suggest that E. chrysorrhoea populations are phenologically adapted to their local host plants, and that the presence of foliage is a key element in the phenological shift reported on A. unedo. These results may have implications with respect to the formation of E. chrysorrhoea host races.

Cork oak pests: a review of insect damage and management

“…However, in contrast to the pine defoliator, E. chrysorrhoea larval development during autumn-winter greatly depends on the presence of leaves on the host plant. On deciduous plants, larval winter diapause is longer, while on evergreen hosts, like for example the strawberry tree Arbutus unedo L., larvae feed during winter as long as the weather conditions allow it (Frago et al 2010). The opportunity to eat for a longer period leads to increased larval size (Frago et al 2010) and probably also reduces larval mortality, as verified for other overwintering lepidopteran larvae (Battisti et al 2005).…”

“…On deciduous plants, larval winter diapause is longer, while on evergreen hosts, like for example the strawberry tree Arbutus unedo L., larvae feed during winter as long as the weather conditions allow it (Frago et al 2010). The opportunity to eat for a longer period leads to increased larval size (Frago et al 2010) and probably also reduces larval mortality, as verified for other overwintering lepidopteran larvae (Battisti et al 2005). Similarly, being the cork oak an evergreen tree, we assume that E. chrysorrhoea larvae may benefit of the same advantages as on the strawberry tree.…”

“…This insect species is polyphagous; it feeds on both broadleaf trees and shrubs (Frago et al 2010). It occurs frequently on cork oak, but seldom causing serious damage.…”

Insecta Class: Caterpillars, Butterflies, Moths

“…Its habitat includes coastal Maine and Cape Cod, Massachusetts [69]. It has an affinity for fruit trees but may also be found on elm, oak, hawthorn and blackthorn trees [70]. The hairy, brown caterpillar emerges between April and June (Fig.…”

Phytosanitary problems detected in black truffle cultivation. A review

“…S15 [pdf online]). L. dispar and E. chrysorrhoea are two polyphagous species (Frago et al, 2010;Schultz and Lechowicz, 1986), while T. viridiana is monophagous on Quercus but polyphagous within the taxonomic limits of this genus (Du Merle, 1998). In young trees belonging to Q. ilex species, a complete defoliation can cause the death of the tree.…”