Ligia oceanica (Linnaeus, 1767)

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 : 12

1. Ligia oceanica (Linnaeus, 1767) ( Fig. 2 a , Fig. 3 , Map 2 , Table 4)

A species bound to coastal habitat with human-made structures with plenty of small crevices, like breakwaters, sea dykes and harbour walls. In these habitats, Ligia oceanica can be very common and easily found. Occasionally found further inland but then always near brackish water, e.g. dykes of canals in direct connection to a harbour or tidal rivers close to the sea. The number of observations is low, mainly due to the limited amount of coastal habitat in Belgium. However, an extensive survey in the 1980’s has proved that the species is very common along the coast in the above-described habitat ( TAVERNIER & WOUTERS, 1986). There is no reason to expect that this species is less common nowadays. L. oceanica is nocturnal ( HARDING & SUTTON, 1985) and it can be very hard to find the species when it is hidden, in particular when there are no objects to turn in search for the species like e.g. on wave breakers. Therefore, nocturnal surveys could result in new observations.

The low number of observations ( Fig. 3 ) indicates that the species’ phenology should be interpreted with care. Although, it seems like the species is less commonly found during summer, possibly because of its low desiccation resistance ( DIAS et al., 2013). Therefore, we recommend additional year-round surveys to get a better understanding about the species’ phenology.

Figures

Map 2. Distribution map for Ligia oceanica.

Fig. 2. a, Ligia oceanica; b, Haplophthalmus danicus; c, Miktoniscus patience; d, Trichoniscus pygmaeus; e, Armadillidium pictum; f, Armadillidium vulgare; g, Porcellio dilatatus; h, Porcellio laevis.

Fig. 3. Corrected number of observations per two-month period for Ligia oceanica (N = 13).