Arachnologische Mitteilungen 54

Uloborus walckenaerius and Oxyopes heterophthalmus in Poland 49 the area using pitfall traps (seven per plot) in the burned plot, in the neighbouring heather and a stand of the grass Molinia caerulea (L.) Moench. The traps were exposed all year round. Additionally, we sampled invertebrates form heather, Molinia and pine trees (burned and living) with a sweep net. A bea- ting net was used to take samples from trees; we also sampled invertebrates by beating them from heather and grass onto a metal bowl. Some other neighbouring habitats were also investigated by sweep-netting. The records Two females and one juvenile of Uloborus walckenaerius were found.The species has a very characteristic habitus (Figs 2-3) and genitalia (Figs 4-6). We collected the specimens either with a sweep-net (on 29 May 2015, 28 May 2016 – females) or by sampling with a metal bowl from heather (on 16 Sep- tember 2016 – juvenile). The three specimens were found in places dominated by heather Calluna vulgaris (L.) Hull: in one case this was a patch of compact, old Calluna -shrubs (Fig. 7); in the other – a dune fairly densely covered with heather; the juvenile was found in small Calluna upgrowth (Fig. 8), 18 months after prescribed fire was applied to rejuvenate heather in this plot. Oxyopes heterophthalmus is easily distinguished from its congeners by the genital structure (Fig. 9-12).The single male of this species was found in a pit-fall trap in the plot where prescribed burning was applied (Fig. 8). The exposure time of the trap was 28 May – 21 June 2016, i.e. about 14 months after the fire. Discussion Both species are known from neighbouring countries and their occurrence in Poland was to be expected.They were re- corded in Saxony and Brandenburg (Platen et al. 1999, Bal- kenhol & Haase 2013, Kielhorn 2016, Arachnologische Ge- sellschaft 2017) fairly close to the country border. These two regions share similar habitats, there is also a plenty of former and contemporary military training areas where large heath- land patches persist. Uloborus walckenaerius was also recorded at similar latitudes to the present location, for example in the southern part of England (Locket & Millidge 1951, Denton 1999a, British Arachnological Society 2017), in Belgium and the Netherlands (van Helsdingen 1999). It is rare in Central Europe – in Germany the species was reported from just few places (Arachnologische Gesellschaft 2017); in the Czech Republic it was only found in the southern part of Moravia (Czech Arachnological Society 2017). Oxyopes heterophthal- mus has similar distribution to that of U . walckenaerius in this part of Europe, but it seems to be even rarer, as shown by the example of the British Isles – where it is present in only few Figs 2-3: Uloborus walckenaerius , female habitus. 2. Dorsal, 3. Ventral Figs 4-6: Epigyne of Uloborus walckenaerius . 4. External view, 5, 6. Inter- nal structures (ventral view) Figs 7-8: Heathland, habitat of Uloborus walckenaerius . 7. Mature heath- land with compact Calluna , 8. Regenerating heathland, 17 months after applying prescribed burning (25 Aug 2016)