Agroecosystems are subject to regular disturbances that cause extinction or migration of much of their fauna, followed by recolonization from surrounding refuges. In small-sized aeronaut spiders, such recolonization is potentiated by their ability to rappel and balloon. These are complex behaviors that we hypothesized to be affected by neurotoxins, namely, neonicotinoids. We tested this hypothesis using two common farmland spider species, Oedothorax apicatus (Linyphiidae) and Phylloneta impressa (Theridiidae). The spiders were topically exposed by dorsal wet application or tarsal dry exposure to commercial neonicotinoid formulations Actara 25 WG, Biscaya 240 OD, Mospilan 20 SP and Confidor 200 OD at concentrations that are recommended for application in agriculture. Contact exposure to neonicotinoids suppressed the ability of spiders to produce the major ampullate fiber and anchor it to the substratum by piriform fibrils. Contact exposure to neonicotinoids also suppressed the ballooning behavior that was manifested by climbing to elevated places, adopting a tiptoe position and producing silk gossamer in the wind. Impaired ability of affected common farmland spiders to quickly recolonize disturbed agroecosystems by silk-mediated dispersal may explain their decline in multiple farmland ecosystems, in which neonicotinoids are applied.
- MeSH
- ekosystém * MeSH
- farmy * MeSH
- hedvábí metabolismus MeSH
- insekticidy farmakologie MeSH
- neonikotinoidy farmakologie MeSH
- pavouci metabolismus MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Neonicotinoids are very effective in controlling crop pests but have adverse effects on predators and pollinators. Spiders are less sensitive to neonicotinoids compared to insects because of the different structure of their acetylcholine receptors, the binding targets of neonicotinoids. We tested whether short-term exposure to neonicotinoids affected the predation rate in different densities of prey of spiders and led to their paralysis or eventual death. To examine these effects, we topically exposed dominant epigeic, epiphytic and sheet-weaving farmland spiders to four widely used neonicotinoids (imidacloprid, thiamethoxam, acetamiprid and thiacloprid). We applied the neonicotinoids at concentrations recommended by the manufacturers for spray application under field conditions. Short-term exposure to the formulations of all four tested neonicotinoids had adverse effects on the predation rate of spiders, with imidacloprid (Confidor) associated with the most severe effects on the predation rate and exhibiting partial acute lethality after one hour (15-32%). Acetamiprid also displayed strong sublethal effects, particularly when applied dorsally to Philodromus cespitum. Day-long exposure to dorsally applied acetamiprid or thiacloprid led to paralysis or death of multiple Linyphiidae spp., with the effects particularly prominent in males. To conclude, we provided multiple lines of evidence that short-term exposure to neonicotinoids, which were applied at recommended field concentrations, caused severe health effects or death in multiple families of spiders. Even acetamiprid caused strong effects, despite being subject to less strict regulations in the European Union, compared with those for imidacloprid because of claims of its negligible off-target toxicity.
Members of the genus Gnaphosa belong to the largest gnaphosid spiders. They are particularly interesting in nature conservation as their distribution is mainly restricted to disappearing natural non-forest habitats. In Europe, several Gnaphosa species groups occur. The exclusively Palaearctic group G. bicolor is characterised by a retrolaterally-shifted embolus, which occupies at least part of the middle one-third of the palpal bulb; females have laterally expanded epigyne and often have very elongated median epigynal ducts (Ovtsharenko et al. 1992). So far four species of this group have been identified in Europe, with a fifth species found in Central Asia (G. tarabaevi Ovtsharenko, Platnick Song, 1992). Two of the European species, G. bicolor (Hahn, 1831) and G. badia (L. Koch, 1866), are well known and their taxonomy and nomenclature is stable, but the same does not hold true for the other two.
During faunistic research of reed beds associated with lakes in the Pannonian region of Czechia we found an Enoplognatha species with spectacular morphology of the male chelicerae. Despite this species being found in an arachnologically well researched area, and that the European species of the genus Enoplognatha have been recently revised (Bosmans & Van Keer 1999), it appears to be a new species.
- MeSH
- druhová specificita MeSH
- mitochondrie genetika MeSH
- mokřady MeSH
- pavouci anatomie a histologie klasifikace genetika MeSH
- sekvenční analýza DNA MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- dopisy MeSH
- Geografické názvy
- Česká republika MeSH
