Genus: Dictyna

This work summarises data on the spider fauna (Araneae) of the Šumava Mts. (Bohemian Forest, Böhmerwald) National Park and Protected Landscape Area (southwest Bohemia), in the period 1858–2023. We abstracted data from all available literature and our own research initiated in 1971. In our own research, we focused on all available habitats, both natural ones and those influenced by humans. These included namely peat bogs, mountains forest, mountain meadows, wetlands, riverbanks and buildings. Altogether, we identified a total of 455 spider species, many of which belong among rare and endangered in the Czech Republic. Overview of their ecological preferences and importance for nature conservation are provided. Within the Czech Republic, nine species are found only in Šumava: Carorita limnaea, Centromerus dilutus, Dictyna major, Gnaphosa badia, Gnaphosa microps, Micaria aenea, Pardosa ferruginea, Pardosa hyperborea and Cybaeus tetricus. The last mentioned species is the first record for the Czech Republic.

The spatial distribution of parasitoids is closely linked to the distribution and ecological requirements of their hosts. Several studies have documented changes in the fauna composition of parasitoids in response to elevation, but data on parasitoids associated with spiders are missing. The koinobiont ichneumonid wasp Zatypota anomala is strictly specialised on spiders of the genus Dictyna (Dictynidae) in Europe. We examined the distribution of spiders of the family Dictynidae in forest ecotones in central Europe across a broad elevation gradient (110–1466 m a.s.l.). We checked the spiders for parasitism by Z. anomala. It was most abundant at the mid-elevations (median 712 m a.s.l., range 179–870 m a.s.l.). We identified four dictynid spider species as Z. anomala hosts. These were Dictyna arundinacea, Dictyna uncinata, Nigma flavescens, and Nigma walckenaeri. All four species and the genus Nigma were recorded as hosts for the first time. The parasitoids strongly preferred juvenile instars of their hosts. The body length differed between parasitised Dictyna and Nigma spiders (medians: 1.95 mm and 2.55 mm, respectively). The distribution of Dictyna and Nigma spiders overlapped along the elevation gradient, but parasitism incidence significantly differed between spider genera along the elevation gradient. Nigma was parasitized at lower elevations between 179–254 m a.s.l. and Dictyna at higher elevations between 361–870 m a.s.l. The phenology of Z. anomala is closely tied to the univoltine life strategy of its host spiders. The parasitoid female oviposits in autumn, and its offspring overwinter as larvae on the host, reach adulthood during spring, and pass the summer as an adult.