Trichoniscus pusillus Brandt, 1833

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 : 40

15. Trichoniscus pusillus Brandt, 1833

( Fig. 17 , Map 15 , Table 17)

Similar to T. provisorius ( Fig. 11 h ), the habitat preferences of Trichoniscus pusillus are probably biased towards forest habitat (see the notes for Trichoniscus provisorius ). However, there is no doubt that forest habitat is one of the major habitats for T. pusillus , where it reaches high numbers. This small species is drought sensitive and reaches its highest numbers in forest interiors rather than forest edges ( DE SMEDT et al., 2018d). T. pusillus is a very common species and much more widespread compared to T. provisorius .

The number of observations shows a small decline for anthropogenic and open landscape habitats during summer months ( Fig. 17 ) (supported by DE SMEDT et al., 2021). This is however not the case for forest habitat. The smaller decline in number of observations during the summer months compared to T. provisorius , can possibly be attributed to its slightly larger size and therefore higher drought resistance.

Figures

Map 15. Distribution map for Trichoniscus pusillus.

Fig. 17. Corrected number of observations per two-month period for Trichoniscus pusillus (N = 326).

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.