Arachnologische Mitteilungen 54

30 S. Korenko, K. Kysilková & Ľ. Černecká 9 mm and reached the final stage and induced changes in spider behaviour. Parasitized A. angulatus constructed a 3D tangle of silk (the cocoon web) at the end of the strong silk line in the top corner of the experimental arena (Fig. 2).The cocoon web of P. longa was decorated by various forms of silk tufts (Fig. 3), which were produced after modification of the spider’s behaviour presumably induced by the larval effect.The tufts were produced in various parts of the cocoon web. The highest number of tufts was on a wall of the silk chamber, which surrounded the parasitoid pupa (Fig. 3a), on threads in the surroundings of the chamber (Fig. 3b) and on a frame thread (Fig. 3c). The parasitoid larva paralysed and killed the spider, and built its cocoon at the centre of this 3D tangle. The cocoon was fusiform, white, sparsely spun with an opening at a distal end and oriented horizontally at an angle of 40°. On the next day (25th October 2016), the larva pupated and three days la­ ter meconium (the first excrement after pupation) appeared in the lower part of the cocoon (27th October 2016). One adult female emerged after 8 days (5th November 2016). Araneus sturmi (body length 4.5 mm) had a parasito­ id larva sitting transversely at the dorsal and posterior side of the spider’s opisthosoma (Fig. 4). Under the influence of the final stage larva of P. tuberosa the spider built a unique three-dimensional (3D) structure in the upper corner of the experimental arena with a high density of threads (Fig.5). No tuft-like structure was observed. The cocoon was fusiform, yellowish white, sparsely spun with an opening at a distal end and oriented horizontally as for P. longa . Discussion Host utilisation and specificity of European Polysphincta Our study supports the view of Fritzén & Shaw (2014) that P. longa is exclusively associated with A. angulatus .This arbo­ real spider is a relatively rare species and prefers natural forest habitats, where it builds a large orb web mostly in the higher strata of canopies. The host’s rareness seems to be one of the reasons why P. longa has been seldom reared from hosts. In addition, P. longa is potentially more abundant in Europe than previously thought because Fritzén & Shaw (2014) re-exami­ ned material from several parts of Europe and revealed that P. longa was misidentified as P. boops , which is also associated with arboreal araneid spiders but attacks only the genus Ara- niella (e.g. Fitton et al. 1988, Fritzén & Shaw 2014, Korenko et al. 2014). The hosts of both parasitoids occur in tree crowns but their microhabitat preferences, the sizes and orientations of their orb webs, and their body sizes differ considerably. Large Fig. 3: Silk tufts produced by the spider under the influence of P. longa larva a. on the wall of the silk retreat; b. on threads in the surround- ings of the retreat; c. on the dragline thread; Scales: 2 mm