Cylisticus convexus (De Geer, 1778)

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 : 68

28. Cylisticus convexus (De Geer, 1778)

( Fig. 20 b , Fig. 32 , Map 28 , Table 30)

Cylisticus convexus has recently been found in only nine locations but widely spread across the country ( Map 28 ). The species is exclusively found in habitat with some degree of anthropogenic influence. Two observations were made in coastal habitat under stones from dykes and riverbank reinforcements. Inland, there is an observation in a city garden, one at an old railway station, two on farms and three observations were made in old quarries. Most observations report only one or a few specimens. Only in some quarries, the city garden and one of the farms, larger numbers were found. Probably this species is transported very often via human activity and can be expected to appear everywhere in the country in random locations. It is a thermophilic species ( VANDEL, 1962), which can only establish populations in warm microsites. The habitat in Belgium corresponds to the habitat in Great Britain, where the species is more often recorded ( HARDING & SUTTON, 1985; GREGORY, 2009).

There is only a limited number of observations which does not allow conclusions based on the phenology diagram ( Fig. 32 ). Although, C. convexus is a thermophilic species we expect it to be more active during summer months, especially in open landscape habitats.

Figures

Map 28. Distribution map for Cylisticus convexus.

Fig. 20. a, Eluma caelata; b, Cylisticus convexus; c, Porcellio monticola; d, Porcellio scaber; e, Porcellio spinicornis; f, Porcellionides pruinosus; g, Porcellium conspersum; h, Trachelipus rathkii.

Fig. 32. Corrected number of observations per two-month period for Cylisticus convexus (N = 10).