No abstract

Grazing by large herbivores is well-known to influence plant communities, while much fewer studies have been carried out on grazing effects on invertebrates. In Norway, some 2.2 million sheep graze on outlying pastures during summer, most of them in the alpine zone, but no study has reported the relative impact of sheep grazing on invertebrate communities relative to other environmental factors such as the plant community and altitude. A fully replicated landscape-scale experiment (2.7 km 2 ) was performed with no, low (25 per km 2 ) and high (80 per km 2 ) sheep densities in an alpine habitat of Norway (1050-1300 m a.s.l.). The increased vulnerability hypothesis (H 1 ) predicts that the more folivorous invertebrates, the higher the grazing pressure by sheep, as large herbivore grazing may stress the plants so they are more vulnerable to insect herbivory. The increased defence hypothesis (H 2 ) predicts increased levels of general anti-herbivore defences, and thus a lower abundance of invertebrates with increasing sheep densities. Contrary to both predictions, no evidence was found that sheep grazing affected invertebrate richness, or abundance of folivorous, predatory or detritivore invertebrates -in a community dominated by Diptera and Hemiptera. Demonstrating an effect will always be a function of sample size, but at least our study shows that other environmental variables (such as plant species richness and functional plant richness) are more important determinants than sheep grazing for the selected invertebrate groups. Our study was short-term (first year of grazing) mainly designed to test specific hypotheses related to induced plant defences; long-term effects are probably owing to the impact sheep may have on vegetation composition, primary production, litter cover and soil properties.

The literature on how plants respond to grazing and other disturbance factors have advanced greatly in recent decades, but studies of invertebrates are comparably few. We here quantify the effects of 3 levels of sheep grazing on selected invertebrates in an alpine ecosystem in Norway. We tested the hypothesis that invertebrates are more sensitive to grazing than plants (responding mainly at high density), and that primary consumers (herbivorous beetles) are more sensitive than predatory species (beetles and spiders). We captured 1218 specimens belonging to 44 beetle species and 6672 specimens belonging to 66 species of spiders. The community was dominated by few species: 5 beetle and 3 spider species made up 53.0% and 37.4% of the catch, respectively. At the local (plot) scale, most negative responses were only recorded at high sheep density, and invertebrates were thus not more responsive than the plant community. Two dominant herbivorous beetles responded to grazing while 3 dominant species of predatory beetles did not (one marginally). Spider species richness and frequency of occurrence of 2 dominant species were negatively affected by sheep grazing, suggesting variation between different taxonomic groups of predators. Further functional details than simple classification like herbivorous, predatory and litter-dwelling invertebrates seem to be required before a framework to predict responses to disturbance are robust. Zusammenfassung In den letzten Dekaden haben die Veröffentlichungen darüber zugenommen, wie Pflanzen auf Beweidung und andere störende Faktoren reagieren, Untersuchungen in Bezug auf Invertebraten sind jedoch vergleichsweise selten. An dieser Stelle quantifizieren wir die Effekte von 3 Intensitäten der Schafsbeweidung auf ausgewählte Invertebraten eines alpinen Ökosystems in Norwegen. Wir untersuchten die Hypothese, dass die Invertebraten gegenüber der Beweidung empfindlicher sind als die Pflanzen (die hauptsächlich bei hohen Dichten reagieren), und dass die primären Konsumenten (herbivore Käfer) empfindlicher sind als räuberische Arten (Käfer und Spinnen). Wir fingen 1218 Individuen, die zu 44 Käferarten, und 6672 Individuen, die zu 66 Spinnenarten gehörten. Die Lebensgemeinschaft wurde

(1) We document the invertebrate fauna collected from 24 oak canopies in east and west Norway as a contribution to the Norwegian Biodiversity Information Centre’s ‘The Norwegian Taxonomy Initiative’. (2) A snap-shot inventory of the canopies was recorded by means of emitting a mist of natural pyrethrum into the canopies at night using a petrol-driven fogger and collecting the specimens in butterfly nets spread on the ground under the canopy. (3) Almost the entire catch of more than 6800 specimens was identified to 722 species. Out of 92 species new to the Norwegian fauna, 21 were new to science and, additionally, 15 were new to the Nordic fauna. Diptera alone constituted nearly half of the species represented, with 61 new records (18 new species). Additionally, 24 Hymenoptera (one new species), six oribatid mites (two new species) and one Thysanoptera were new to the Norwegian fauna. (4) Our study emphasizes the importance of the oak tree as a habitat both for a specific fauna and occasional visitors, and it demonstrates that the canopy fogging technique is an efficient way to find the ‘hidden fauna’ of Norwegian forests. The low number of red listed species found reflects how poor the Norwegian insect fauna is still studied. Moreover, the implication of the IUCN red list criteria for newly described or newly observed species is discussed.

Hymenoptera, Diptera, and Lepidoptera; most species are associated with Hemiptera in the superfamilies Coccoidea, Aleyrodoidea, and Aphidoidea (Yasnosh, 1995). The species of the genus Aphelinus are parasitoids of sap-sucking aphids in Aphidoidea (Hemiptera). Aphids are of quite considerable economic importance, as they damage many horticultural, forest, and fruit plants, and are the cause of leaf distortion and flagging terminals. Infested plants have reduced growth and vigor. With severe infestations, leaf yellowing and twig dieback may occur. Species of Aphelinus have been used in biocontrol against many aphid pests, most successfully Aphelinus mali for the biological control of Eriosoma lanigerum (Hausmann), the apple woolly aphid (Nikolskaya and Yasnosh, 1966; Yasnosh, 2002). The latest works on Aphelinus from Europe were done by Japoshvili and Abrantes (2006) and Japoshvili and Karaca (2009). The aim of this study was to review genus Aphelinus species housed in the Natural History Museum of Oslo University in order to record the fauna of Aphelinus species of Norway. 2. Materials and methods The Aphelinus collection housed in the Natural History Museum of Oslo University was studied. The material was collected during 1953-2008 using all major methodologies for Aphelinidae including direct rearing from the host, sweeping, yellow-pan traps, and Malaise traps. Terminology follows that of Nikolskaya and Yasnosh (1966), Graham (1976), and Yasnosh (1963-2002). The following abbreviations are used in the text: AOL, anterior ocellar line (the shortest distance between the anterior and posterior ocelli); DAO, diameter of anterior ocellus; DPO, diameter of posterior ocelli; EL, maximum eye length; F1, F2, etc., first funicle segment, second funicle segment, etc.; FV, maximum frontovertex width; GL, maximum gonostylus (third valvula) length; GW, gonostylus width; MS, malar space (the shortest distance from the eye to the mouth margin); MSL, malar space (distance from eye margin to clypeus); MT, midtibia length; OOL, ocular-ocellar line (the shortest distance between posterior ocellus and adjacent eye margin); POL, posterior ocellar line (the shortest distance between the posterior ocelli). Specimens were card-mounted and slides were done according to Noyes's (2013) methodology. The collection of Aphelinus spp. is located in the Natural History Museum of Oslo University Norway as all type material of new species. For identification, we used a binocular stereomicroscope "MICROS" model: MS1107/MZ1280/ MC1280. Drawings were done by the first author by hand.