Microhabitat selection by ovipositing females and pre-diapause larvae of a Welsh population of Euphydryas aurinia (Lepidoptera: Nymphalidae)

Abstract

Habitat requirements of the marsh fritillary Euphydryas aurinia have been studied intensively in recent years in order to inform conservation action on this rapidly declining species. Autecological studies have been undertaken on various spatial scales to account for differences in mobility between life stages. It has become clear that resource utilisation by the species varies between different geographic areas and also on a local scale. We studied the microhabitat surrounding Succisa pratensis plants chosen for oviposition and around resulting larval webs in a key Welsh population, UK. Microhabitat preferences were shown to differ between ovipositing females and pre-diapause larval groups. For oviposition, females showed a preference for host plants within clusters of S. pratensis surrounded by a relatively low sward. In contrast, larval webs were found in relatively high vegetation with relatively low S. pratensis cover in the immediate vicinity. The marked difference between oviposition and larval web microhabitat was achieved through very long distance dispersals undertaken by the pre-diapause larval groups. This gives rise to questioning the common assumption that pre-diapause larval web location can be used as a proxy for oviposition location. It also underpins the importance of managing E. aurinia habitats for maximum structural variability on a small scale.