Ligidium hypnorum (Cuvier, 1792)

Boeraeve, Pepijn, Arijs, Gert, Segers, Stijn, Smedt, Pallieter De, Spinicornis & Utm, Belgium. Every grid cell of the, 1908, Habitat and seasonal activity patterns of the terrestrial isopods (Isopoda: Oniscidea) of Belgium, Belgian Journal of Entomology 116, pp. 1-95 : 14

2. Ligidium hypnorum (Cuvier, 1792)

( Fig. 4 , Fig. 11 a , Map 3 , Table 5)

Deciduous forest is the most important habitat for Ligidium hypnorum and in this habitat the species is very common and can occur in high numbers. As a drought-sensitive species, L hypnorum prefers wet conditions in forests and an important share of the observations were made along ditches, streams and riverbanks in forests ( Table 5). In Belgium (and across Western Europe), the species seems to strongly favour forest interiors because they have a higher humidity compared to forest edges ( DE SMEDT et al., 2018d). Although L. hypnorum is a characteristic species of closed forest habitat ( DE SMEDT et al., 2020b), the species can also be recorded in gardens, parks, grasslands and at stream- and riverbanks in open landscapes ( Table 5). Since hand collection is more challenging in grasslands and other open habitats, the species could be under recorded in open landscape habitats in the present study. The distribution map shows that the species is less common or absent in certain regions, mostly regions with low deciduous forest cover (like the northern part of the country).

The species was more commonly found in the months March–April, July–August and November–December ( Fig. 4 ). This is probably a random pattern and we assume that L. hypnorum activity pattern is quite constant during the year. Its dominant breeding period is summer (June–July) ( ZIMMER & BRAUCKMANN, 1997), a pattern that is absent in the phenological diagram.

Figures

Map 3. Distribution map for Ligidium hypnorum.

Fig. 4. Corrected number of observations per two-month period for Ligidium hypnorum (N = 345).

Fig. 11. a, Ligidium hypnorum; b, Androniscus dentiger; c, Haplophthalmus mengii; d, Hyloniscus riparius; e, Metatrichoniscoides leydigii; f, Trichoniscoides albidus; g, Trichoniscoides helveticus; h, Trichoniscus provisorius.