Host associations of Coenonympha hero (Lepidoptera: Nymphalidae) in northern Europe: microhabitat rather than plant species

Abstract

Understanding ecological requirements of endangered species is a primary precondition of successful conservation practice. Regrettably, we know surprisingly little about the life history of numerous threatened insects, and about their use of larval host plants in particular. The brown butterflies (Nymphalidae: Satyrinae) have traditionally been considered polyphagous on grasses and indiscriminatory in their oviposition behavior. However, detailed studies on several species have revealed local specialization in host plant use as well as the decisive role of microlimatic conditions as determinants of habitat quality. The present study addresses host plant relationships in the endangered brown butterfly Coenonympha hero (L.) at the northern limit of its European distribution. We combine laboratory-based host preference and performance tests with an analysis of microhabitat use by adult butterflies in the field. Both lines of evidence suggest that C. hero is polyphagous enough not to be associated with one particular host species. Oviposition choices of C. hero are not driven by host plant species but rather by structural characteristics of the substrate. The preferred rigid needlelike structures may serve as cues of 'transparent' vegetation which allows the larvae to benefit from sunlight reaching the lower strata of the tuft. Our results suggest that conservation efforts should prioritize microclimatic parameters, rather than the presence of any particular host plant species, as decisive determinants of habitat quality in C. hero.

Population decline at distribution margins: Assessing extinction risk in the last glacial relictual but still functional metapopulation of a European butterfly

“…As all other Satyrinae, C. hero larvae feed on various types of widespread grass and are not specialized on a particular host plant (Tiitsaar et al, 2016). Neither do they depend on a very particular bi- 4).…”

Adult demography of an isolated population of the threatened butterfly Scarce Heath Coenonympha hero and its conservation implications

“…In breeding experiments, other species were also accepted as larval foodplants, e.g., Festuca ovina and Dactylis glomerata (Cassel et al 2001). However, Tiitsaar et al (2016) suggest that microclimatic conditions are more important determinants of habitat quality than the presence of specific host plants. Larvae overwinter in the 3rd instar in grass tussocks, and they resume their growth in early spring to pupate finally in the 5th instar in May (Cassel-Lundhagen et al 2008).…”

Phytoindication approach to assessing factors determining the habitat preferences of red deer (Cervus elaphus)

“…In animal ecology, plant indicator scales are rarely used to address ecological questions. Significant relationships have been found between plant indicator scales and the diversity of flies (Williams et al, 2009), butterflies (Oostermeijer & van Swaay, 1998;Konvicka et al, 2003;Feest et al, 2014;Tiitsaar et al, 2016;Pielech et al, 2017), and mollusks (Horsák et al, 2007;Kappes et al, 2014). These studies emphasize the advantages of using indicator scales in the study of animal autoecology.…”