How much care does a shrub-feeding hairstreak butterfly, Satyrium spini (Lepidoptera: Lycaenidae), need in calcareous grasslands?

Abstract

Abstract. Many butterfly target species are associated with early successional stages of grasslands. The Blue-spot Hairstreak, Satyrium spini (Denis & Schiffermüller, 1775), is a target species of grasslands. However, it feeds on Common Buckthorn (Rhamnus cathartica), which is associated with late successional stages of grasslands. If S. spini would also be restricted to late seral stages, there might be a management dilemma due to the contrasting requirements of S. spini and other target species. The aim of this study was to determine the oviposition preference of S. spini in calcareous grasslands, and to give management recommendations to promote this species. Therefore, we studied the oviposition microhabitats of S. spini at three representative patches of the Diemel Valley (Central Germany) by comparing environmental conditions on occupied and control host plants. In total we surveyed 1,889 host plants. Altogether we found 148 batches of S. spini on them containing 396 eggs. Most of the eggs were on plants that grew under the warmest conditions. Females preferred to lay eggs on small (< 1.3 m) shrubs of Rh. cathartica fully exposed to the sun growing on steep south-and west-facing slopes. This butterfly showed no difference in its preference for bushes growing in hedges or solitarily. About 80% of the batches of eggs were laid on the upper surface of a twig fork close to the surface of the ground (< 1 m). Our study showed that S. spini is a species characteristic of mid-successional stages of calcareous grasslands. The survival of suitable habitats for S. spini depends on regular management. To achieve this we recommend traditional rough grazing with sheep and goats, which creates open grasslands with small Rhamnus plants. In addition, the shrubs in tall hedges bordering calcareous grasslands should be subjected to cutting on a rotating basis.

Inhabiting warm microhabitats and risk-spreading as strategies for survival of a phytophagous insect living in common pastures in the Pyrenees

“…The importance of a warm microclimate for the immature stages has been described for many thermophilous butterfly species (García-Barros & Fartmann, 2009) and has already been shown for S. spini in Central European lowlands and low mountain ranges (Koschuh et al, 2005;Hermann, 2007;Löffler et al, 2013). In our study area, however, warm microhabitats are likely to be even more important than in Central Europe.…”

“…In our study area, however, warm microhabitats are likely to be even more important than in Central Europe. At the lower altitudes in Central Europe, where the climate is mild (Ellenberg & Leuschner, 2010), this species lays its eggs at heights of up to 1.3 m above the ground and the occurrence of bare ground, rocks or gravel is not a prerequisite for egglaying (Löffler et al, 2013). We assume that the preference for unusually warm microhabitats is explained by the harsh climatic conditions near its altitudinal range limit in the Pyrenees.…”

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

“…It seems that the preference for south-west facing and wellinsolated sites may vary regionally in response to local climatic conditions. We can expect that at the northern limit of range of the species, including Poland, it should prefer sites with the warmest conditions at microhabitat level (Fartmann and Timmermann 2006;Löffler et al 2013). The species' preference for solitary plants or these located in peripheral parts of hedgerows found by us may also indicate importance of warm microclimatic conditions for ovipositing females.…”

“…Surely, decreasing the intensity of hedgerow trimming is preferable in case of oviposition habitats of E. catax. For shrub-feeding butterflies, such as T. betulae and Satyrium spini, a rotational trimming of a quarter of the shrubs every fourth year was also recommended (Fartmann and Timmermann 2006;Löffler et al 2013;Helbing et al 2015). It seems that this solution may also be appropriate to reduce the heavy egg losses in case of E. catax.…”

Larval habitat preferences of a threatened butterfly species in heavy-metal grasslands

“…Anthes et al 2003), and at each of these available microhabitats, the same parameters were measured as described above. The number of available microhabitats corresponded to the proportional area of each patch (Krämer et al 2012;Löffler et al 2013). Moreover, larval microhabitats occupied by A. niobe in Stolberg were compared with larval microhabitats of the previously published study from Langeoog (Salz and Fartmann 2009).…”