Winter-green host-plants, litter quantity and vegetation structure are key determinants of habitat quality for Coenonympha oedippus in Europe

Abstract

The knowledge on species' habitat preferences at local scales across its range is an essential condition for 18 defining the most appropriate habitat management for the conservation of any species. In this study, we 19 combined field observations from three European countries with breeding experiments under field conditions to 20 identify oviposition and larval preferences of Coenonympha oedippus on micro-scale level across contrasting 21 habitat types (wet vs. dry). Despite the wide geographical range and the different habitats we found some 22 common features: (i) vegetation structure of the herb layer is an essential factor for oviposition site electivity and 23 successful development of premature stages; (ii) high cover of litter and/or dwarf shrubs in the microhabitat 24 (larval: 45-70% , oviposition: 40-50%) creates a herb layer rich in gaps; at their edges eggs are deposited and 25 the caterpillars are adequately sun-exposed; (iii) egg-laying females are not selective regarding oviposition 26 substratum; (iv) oviposition height is adjusted to positions with direct sunlight or warm substratum; (v) the host-27 plants coverage in oviposition sites was high: 45 and 50% (wet), 18% or 41% (including potential host-plants) 28 (dry); (vi) the most important host-plant is Carex panicea (wet) and Carex humilis (dry), but Molinia caerulea 29 (wet) and Festuca rupicola (dry) are also used regularly; (vii) the availability of winter-green host-plants in the 30 vicinity of hibernated larvae plays a substantial role in their survival. As regular mowing or grazing would 31 remove the litter and destroy the gaps, the management should be restricted to selective reed cutting or manual 32 shrub removal. Only selective mowing during winter (December-February) can be recommended for keeping 33 the habitat open where the reduction of bushes is not sufficient. 34 35

Oviposition site selection of a threatened moth Eriogaster catax (Lepidoptera: Lasiocampidae) in agricultural landscape—implications for its conservation

“…The development of effective conservation strategies and management of E. catax across its geographical range, should be based on a detailed knowledge about the species habitat requirements at local scales (Anthes et al 2008;Čelik et al 2015). Understanding of a species' oviposition preferences may be of crucial importance, because oviposition itself represents the spatial inference between all successive life stages and the environment (Čelik 2013).…”

Oviposition-site preferences of a declining butterfly Erebia medusa (Lepidoptera: Satyrinae) in nutrient-poor grasslands

“…Together with the presumed importance of the litter layer as a microclimatic buffer, this might explain why E. medusa is so dependent on grasslands with a very low land-use intensity. Consistent with this hypothesis, two other satyrine species (E. aethiops and C. oedippus), which exhibit egg-laying patterns similar to those of E. medusa, are also restricted to abandoned or very slightly used habitats (leopold, 2006;Bräu et al, 2010;Čelik & Verovnik, 2010;Slamova et al, 2013;Čelik et al, 2015).…”

“…Al-though the amount of litter did not differ between occupied and unoccupied plots within occupied patches (this study), it was the most important factor that limited the occurrence of E. medusa at the habitat level in the Diemel Valley (Stuhldreher & Fartmann, 2014). litter accumulation is also a striking characteristic of the habitats and oviposition sites of E. aethiops, a sibling species of E. medusa, which inhabits open woodlands (leopold, 2006;Slamova et al, 2013), and some other satyrine species such as Coenonym pha hero (Bräu & Dolek, 2013), C. oedippus (Bräu et al, 2010;Örvössy et al, 2013;Čelik et al, 2015) and Lopinga achine (Streitberger et al, 2012). The immature stages of these species probably require a stable and relatively humid microclimate during hibernation and pupation (leopold, 2006).…”

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

“…C. hero females have selective oviposition preferring grasses (and perhaps other plants: to be confirmed in the field) with narrow and rigid leaves as substrates. We suggest that such a preference is not adaptive in terms of providing the offspring with a host plant of the 'right' species but is rather 'designed' to provide the larvae with suitable microclimatic conditions (see Krämer et al 2012;Č elik et al 2015; for similar results). The common feature of the preferred F. ovina and P. abies is the presence of narrow and rigid needle-like structures which can therefore be hypothesized to serve as oviposition stimuli for C. hero.…”

“…Being exposed to sunshine is therefore suggested to be a factor largely determining microhabitat suitability for that species (Bräu et al 2010;Č elik et al 2015). We thus hypothesize that the adaptive significance of preferring narrow-leaved grasses is in the 'transparency' of the plant cover: vegetation consisting of plants like certain Festuca spp.…”