Philoscia muscorum (Scopoli, 1763)

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 : 50

19. Philoscia muscorum (Scopoli, 1763)

( Fig. 19 c , Fig. 23 , Map 19 , Table 21)

Philoscia muscorum is very common in all kind of habitats across the country and maybe the most eurytopic species in Belgium. Its habitat preferences ( Table 21) closely resemble the pattern observed for Oniscus asellus . Although, this species is very common in forest habitat, it is always less abundant compared to O. asellus (e.g. DE SMEDT et al., 2016b, 2018b). In open landscape on the contrary, P. muscorum is very often the more abundant species compared to O. asellus (unpublished data from pitfall research).

The corrected number of records are highest from November until April in both open landscape and anthropogenic habitats ( Fig. 23 ). In forest habitat the corrected number of records is only somewhat lower in September–October and somewhat higher in November–December. Despite having a higher drought resistance than O. asellus ( DIAS et al., 2013) , the drop in records during summer months is considerably bigger for P. muscorum than for O. asellus . This may be explained by the different strategies the species have to avoid desiccation. O. asellus tends to shelter in a locally more humid spot (for instance under bark of dead wood) whereas P. muscorum will run further to search for more humid shelter places. This could mean that during summer months P. muscorum is harder to detect compared with O. asellus , when searching by hand. Using pitfall traps, DE SMEDT et al. (2021) found however an activity peak in spring compared to other seasons.

Figures

Map 19. Distribution map for Philoscia muscorum.

Fig. 19. a, Oniscus asellus; b, Philoscia affinis; c, Philoscia muscorum; d, Platyarthrus hoffmannseggii; e, Armadillidium album; f, Armadillidium nasatum; g, Armadillidium opacum; h, Armadillidium pulchellum.

Fig. 23. Corrected number of observations per two-month period for Philoscia muscorum (N = 1071).