Platyarthrus hoffmannseggii 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 : 52

20. Platyarthrus hoffmannseggii Brandt, 1833

( Fig. 19 d , Fig. 24 , Map 20 , Table 22)

Platyarthrus hoffmannseggii is the only strict myrmecophilous species in Belgium. It lives in ant nests of a wide variety of species ( BERG, 1995), where it scavenges on ant brood and ant prey but probably also feeds on other organic material in the nest ( PARMENTIER et al., 2017). It is commonly found across the country ( Map 20 ). The species has been recorded in a wide range of habitats in open landscapes and anthropogenic habitat ( Table 22). It is most commonly found on graveyards, grasslands, near roads and buildings in open landscape and in gardens and parks. The species is rare in forest habitat and in this habitat probably confined to forest edges and very open forest types.

The months with most records of P. hoffmannseggii are strongly linked to the phenology of ants. From May until October the corrected number of records is highest with a small decrease in November–December ( Fig. 24 ). In anthropogenic habitat, the number of records peaks already in May–June. In open landscape, the increase happens more gradually and only starts to peak in July. The relative high number of records stays constant until November–December. The phenology shows a two-month shift in open landscapes compared to anthropogenic habitats, which can probably be attributed to the resulting consequences of the urban heat island effect on ant phenology ( CHICK et al., 2019). Although, P. hoffmannseggii is a drought-sensitive species ( DIAS et al., 2013), its phenology seems to be shaped by its host activity rather than by environmental variables. In forests, we do not see a clear phenological pattern, possibly due to the low number of records in this habitat.

Figures

Map 20. Distribution map for Platyarthrus hoffmannseggii.

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. 24. Corrected number of observations per two-month period for Platyarthrus hoffmannseggii (N = 163).