No description available.

No description available.

Aspects of the distribution and ecology of some surface-dwelling invertebrates were examined on different high-altitude vegetation types in the north Pennines, England. The influence of the boundary between habitats on the invertebrate community was also investigated, and the effects of habitat heterogeneity on invertebrate distribution were discussed. Spiders and carabids were sampled from the dominant vegetation types on the plateaux of three mountain summits (Cross Fell, Littie Dun Fell and Great Dun Fell) in 1991 using pitfall traps. Multivariate methods were used to classify and ordinate the sites based on their fauna and to assess the influence of the local environmental variation on the species distribution. Three spider assemblages were recognised based on their common species composition; two short Festuca grassland assemblages and a Nardus/Eriophorum assemblage associated with greater vegetation density. The results suggest that variation in the vegetation structure is the major factor influencing spider distribution on the summit plateaux, with slope and soil depth also contributing. The carabids appeared too widely distributed to assign to any specific vegetation types. The influence of the interface between different vegetation types on the spider and carabid fauna was sampled using pitfall traps in 1992-3. At the boundary between two highly contrasting habitats (sheep pastures and conifer plantations) an edge effect was found in both groups, where species richness was elevated. The major contribution to this increase was the mixing of both pasture and plantation species, species specific to the interface were few. The edge effect at this interface was narrower but larger in spiders than in carabids. At the boundary between two more similar habitats (grazed and ungrazed upland grassland) the edge effect was much reduced, species richness was not elevated, and the level of overlap between habitats was much wider. Edge permeability, structural similarity and altitude were considered the most important factors for the differences between boundaries studied. It is inferred that in the high altitude invertebrate community most species are widespread crossing boundaries between vegetation types regularly, though some species may have affinities to particular habitats for different aspects of their ecology. The implications that this study has for understanding the effects and impacts of habitat heterogeneity at the landscape level are discussed, such as invertebrate movement patterns, population dynamics and management aspects.

Slugs are important pests in many agricultural crops and potential biological control agents are being studied as an alternative to molluscicide application. The role of the carabids Pterostichus madidus (Fabricius) and Nebria brevicollis (Fabricius) as predators of the slug Deroceras reticulatum (MUller) was examined in the laboratory. These generalist beetle species were only capable of killing small, healthy slugs (<0.1 ig) as they were unable to overcome the defence mucus production of larger slugs. Dead slugs were scavenged in preference to killing healthy slugs. The relatively high proportion of positive serological results from field caught carabids may reflect a high scavenging rate rather than actual predation on live slugs. Slugs are difficult prey items for generalist beetles to overcome due to their defence mucus production. Results suggest that few slugs will be consumed in the presence of alternative prey which are less difficult for beetles to overcome. Slugs which could no longer produce defence mucus were readily attacked by both beetle species. Although beetles killed few healthy slugs the presence of beetles influenced slug behaviour with slugs of all sizes foraging for shorter periods of time. Any reduction in slug activity on the soil surface would in turn lead to a reduction in seedling damage. The results suggest that the role of potential predators in pest control can only be evaluated fully with a detailed understanding of their behaviour.

Thesis (Ph. D.)--Oregon State University, 1966. / Typescript. Includes bibliographical references (leaves 331-355). Also available on the World Wide Web.

Thesis (M. Ag. Sc.)--University of Adelaide, Dept. of Entomology, Waite Agricultural Research Institute, 1989. / Includes bibliographical references.

Diss. (sammanfattning) Uppsala : Univ., 2009. / Härtill 5 uppsatser.

Thesis (M.S. in mechanical engineering)--Washington State University. / Includes bibliographical references.

Thesis (Ph. D.)--University of Michigan, 1938. / Title from the commencement program of University of Michigan. Each part has caption title only. Thesis note on slip mounted on first page of part one. "Contribution[s] from the Biological station and the Department of zoology, University of Michigan." Reprinted from papers of the Michigan Academy of Science, Arts, and Letters, vol. xxv, 1939; Transactions of the American Microscopical Society, vol. LIX, no. 3, July, 1940 and Ecology, v. 21, no. 2, April 1940, respectively. "Literature cited" at end of each part.

Thesis (M.S.)--University of Wisconsin--Madison, 1967. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.