Thesis (Ph. D.)--University of Wisconsin--Madison, 1971. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--Cornell University, 1919. / "Reprinted from Canadian Department of agriculture, Entomological branc, Bulletin 14, part II, 1918." Includes the t.p. of the original issue. Bibliography: p. 139.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1975. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Bibliography: leaves 175-182.

Thesis (M.S.)--University of Wisconsin--Madison, 1983. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 203-236).

281 species of terrestrial ground-living beetles were recorded from 69 riparian and wetland sites in the floodplain of the lowland River Soar, England. Differences in species composition between pitfall trapped and timed hand-collected samples were smaller than those attributable to environmental and seasonal factors. Detrended Correspondence Analysis consistently ranked all sites against seasonal variations between April and June and floodplain sites against annual variations. DCA axis 1 scores were slightly better correlated with important environmental variables at the ecohabitat (<5Om) scale rather than the microhabitat scale. Canonical Correspondence Analysis detected assemblage responses to flooding disturbance and grazing pressure along the main channel as well as to water level stability in the floodplain. A conceptual model of floodplain land-use and river management postulated a dynamic equilibrium between flooding disturbances and vegetational succession, producing geomorphic and vegetational structures which serve as semi-aquatic habitats for terrestrial beetle assemblages with appropriate species traits. Impoundment for navigation affects assemblages by modifying the severity of flooding disturbance. The effects of grazing pressure resemble flooding disturbance. The short-term (< 5yr) impact of bank regrading was explained by differences in severity, predictability and frequency compared to the beetles' generation length. Evenness and species richness were affected only by flooding and grazing disturbance. This response was not predicted by the intermediate disturbance hypothesis because the frequencies of flooding and grazing disturbances in the Soar valley are not appropriate to the hypothesis, which more closely relates to disturbance by bank regrading. In comparison to diversity indices, a rarity index was much less sensitive to environmental factors than species diversity indices and more robust against seasonal and yearly fluctuations. Consequently, it has more potential for use in site quality assessment.

No description available.

Forest insect populations, like many other animal populations, are not uniformly distributed throughout an area but are found in various degrees of concentration regionally and locally. Bark-beetles constitute a major group of economically important forest insects and the causes of their variable concentrations are only partially understood. Among the important circumstances with which variable bark-beetle populations are associated are those encountered in forest stands undergoing cutting practices. In such stands, the conditions affecting bark-beetles vary according to different cutting methods which coincidentally produce different quantities of food in the form of slash, and expose that food, as well as the environment generally to altered micro - and meso - climates. The present investigation was undertaken to determine and explain some of the major factors underlying the variability in concentration of certain bark-beetles in a forest stand cut in certain selected ways. An investigation of this nature may be carried out in an area chosen for this purpose alone, or may be coordinated with a programme already designed for silvicultural purposes. There are advantages and disadvantages either way. The requirements for entomological experimentation are not necessarily best provided by the experimental design which is adequate for silvicultural purposes. On the other hand, the results from such a coordinated study carry the weight of authenticity for representing an actual forestry condition, and not merely a hypothetical case. In addition, the use of the materials provided by a silvicultural study make possible an entomological study which would otherwise be too costly of time and effort. Indeed, one of the chief obstacles to this type of study, heretofore, has been the lack of selectively cut stands. In 1952 the Dominion Forest Service initiated studies on selective cutting of lodgepole pine (Plnus contorta Dougl.) in the foothills region of Alberta. The opportunity was here presented for getting the special forestry conditions for the desired entomological study. The entire entomological Investigation, of which this study is a part, had a broad basis. Ultimately, it is desired to know something of the make-up of the insect complex associated with stands selectively cut in different ways, to learn something of the factors responsible for the variation of concentration, and to observe the effect of the insect population on the forest. The present investigation is an initial study to determine the manner in which the bark-beetles disperse within newly logged regions, and to relate their type of dispersal with the factors common to the environment. The insect complex was made up chiefly of Scolytids, Cerambycids, and Buprestids. Among the species, Ips pini Say. formed the most important component and the one which provided the most suitable data for analytical study. Accordingly the data concerning this species form the basis for the conclusions arrived at in this study. / Science, Faculty of / Zoology, Department of / Graduate

Optimal foraging models generally assume that predators are capable of making appropriate foraging decisions and that these decisions affect fitness. I tested these assumptions in a study of the intertidal beetle Thinopinus pictus Leconte (Staphlyinidae). Adult beetles live on sand beaches in temporary burrows from which they emerge at night to prey on amphipods Orchestoidea californiana (Brandt). I also present some data for isopods Alloniscus perconvexus Dana, a less important prey species. I measured amphipod activity patterns by pitfall trapping, and beetle activity patterns by direct counts of the number of beetles active on the beach in 1-h searches. In general, there was a good correspondence between beetle and amphipod temporal and spatial activity patterns. However, by manipulating the spatial distribution of prey, I showed that beetles arrived at foraging sites independently of prey availability. Prey capture rate was low, with a mean of 75 min between captures, so that beetles were not always successful in obtaining food during a night. Food deprivation for up to 4-d intervals did not affect beetle survival or oviposition rates in laboratory experiments. I constructed models of amphipod size selection by beetles, using the size distributions of amphipods measured on the beach, and the results of laboratory experiments on capture success, reaction distance and feeding rates. Capture success decreased and the probability that an amphipod was detected increased with increasing amphipod size. Beetles observed during beach searches selected larger sizes of amphipods than predicted from availability and vulnerability of different sizes. To apply an optimal foraging model, I estimated the profitability of different sizes of amphipods from the number of amphipods of a given size required to satiate a beetle in the laboratory. Profitability was highest for large amphipods and lowest for small amphipods and isopods. However, amphipod abundance on the beach was always below the threshold at which specialization on larger sizes was predicted to occur. Male beetles were active longer than female beetles during the night, and fewer male beetles were observed feeding. Male beetles tended to be found higher on the beach and to include more isopods in their diet than female beetles. In laboratory experiments I showed that amphipods were highly preferred over isopods by both sexes of beetles. Male and female beetles were approximately the same size and consumed equal numbers of prey items. I conclude that male foraging behaviour was altered by search for mates. I present an optimal diet model for two prey types, based on the expected foraging time required for a predator to reach satiation. Predictions differ in some cases from a model based on maximization of the rate of energy intake. Foraging time may be minimized by a predator which begins as a specialist and then expands its diet to include lower value prey when it is near satiation. Laboratory experiments on Thinopinus give weak support for these predictions, but I present alternative interpretations of the results. I suggest that most invertebrate predators which forage on active prey are limited in their ability to assess variations. in prey abundance. Future studies should emphasize how patchiness in prey availability affects foraging behaviour. / Science, Faculty of / Zoology, Department of / Graduate

Thesis (Ph.D.)--University of the Witwatersrand, Faculty of Science, 1990. / A fauna of mid-Cretaceous Carabidae (Coleoptera), recovered from Orapa Diamond mine, Botswana is described. The carabids are similar to extant forms and include: the first record of a fossil of the subfamily Promecognathinae, Palaeoaxinidium orapensis (gen. et sp. n o v . ); the earliest record of a member of the Scaritinae; and ten specimens which are placed tentatively in the subfamilies Siagoninae (two specimens), Pterostichinae (three specimens), Anchomeninae (one specimen), and Harpalinae (four specimens); in addition two specimens cannot be placed in any particular subfamily. The manner of preservation of the fossils is described, and a taphonomic analysis of the site is attempted. The exact age of the sediments is discussed, and a palaeoenvironment is inferred from a study of the carabids, the rest of the fossil fauna, and the sediments. This fauna of carabids lived in a well-wooded crater formed by the eruption of a kimberlite. The climate of the time was seasonal, warm, and intermediate between tropical and temperate extremes. The morphological conservatism of the promecogna thine, and the apparent conservatism of the way of life of members of this group, provides support for the punctuated equilibrium pattern of evolution.

No description available.