Thesis (M.S. in botany)--Washington State University, August 2010. / Title from PDF title page (viewed on July 22, 2010). "School of Biological Sciences." Includes bibliographical references.

Thesis (Ph. D.)--Ohio state University, 1922. / Cover title. Autobiography. Published in full as Bulletin of the Ohio Agricultural experiment station no. 388, Nov. 1925 (1 p. l., p. 239-364). Bibliography: [3] p. at end.

Summary of Thesis (Ph. D.)--University of Illinois, 1936. / Vita. "Publications": p. [6].

Thesis (M.S.) in Ecology and Environmental Science--University of Maine, 2003. / Includes vita. Includes bibliographical references (leaves 75-86).

Thesis (Ph. D.)--University of Wisconsin, 1967. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliography.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1980. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

This paper presents a study of three phases of the flight of the Douglas-fir beetle, viz: flight preparation and response, flight attitude and movements, and flight capacity. A room equipped with temperature and humidity controls was used for some of the experiments. The wing movements were studied with a stroboscope and flash photography. Flight mills were used in the studies involving flight duration and velocity. The only effect of nemic and mite associates was reduction of the duration of the initial flight caused by internal nematodes. Temperature played an important role in all phases of flight studied. Temperatures from 72° to 89° F. were optimum for spontaneous flight, while 68° F. seemed to be the lower limit of flight in the absence of additional stimuli. In sunlight, spontaneous flights occurred at 63° F. Increasing temperature caused a rapid increase in the wing-beat frequency up to the threshold for spontaneous flight, then increased only slightly to the level of heat prostration. Lower temperatures greatly reduced the duration of the initial flight and caused a broken flight pattern, but failed to influence the over-all flight duration. The effects of relative humidity followed a similar pattern to those of temperature inasmuch as evaporational cooling of the insect occurred at low relative humidities not at high relative humidities. Increased light intensity increased the speed of the flight response and caused slight increases in the wing-beat frequency; both results being attributed to increased nervous stimulation. Studies on the effect of the ehange in the beetles’ activity from dispersal to gallery construction to re-emergence, on the response to flight stimulation, showed that once gallery construction had begun the females became flight refractory, some regaining their inclination to fly after 15 days. On the other hand, the males could be expected to be either flight positive or refractory throughout the duration of gallery construction. The number of individuals responding positively to flight stimulation by tossing increased greatly following the first toss, then diminished until no further change occurred after six tosses. Wing mutilation and loading produced changes in the wing-beat frequency similar to those found by other workers, and indicated that the changes were probably due to altering the inertia of the oscillating system. Fatigue caused a gradual reduction in the wing-beat frequency over a four hour period although the final per cent decrease attributable to fatigue was much lower than that reported for other insects. The flight velocity was of the order of 90 to 115 metres per minute or 3.3 to 4.2 miles per hour, changes in the flight velocity seemingly being related directly to changes in wing-beat frequency. It is concluded from these studies that the Douglas-fir beetle is a strong uniform flier despite the complexity of components affecting several phases of flight. The various thresholds for spontaneous flight were consistently above the levels required for continuation of the activity. The flight of the Douglas-fir beetle can be expected to vary greatly from year to year and from season to season depending on the environmental factors. Of the flight movements it is the wing-beat frequency which is affected the most by environmental changes, thus varying the strength, velocity and magnitude of the flight. The Douglas-fir beetle is capable of an average flight of up to 10 miles immediately following take-off and from between 15 to 20 miles a day for several days; favourable air currents would increase these figures substantially. / Science, Faculty of / Zoology, Department of / Graduate

The behaviour of the ambrosia beetle Trypodendron llneatum (Olivier) has been considered in respect to illumination, body moisture and host factors. The investigation was designed to study potential uses of this insect as a test instrument for chemical studies of host wood attractants. A preliminary study of host attractants was also conducted using a newly-proposed bioassay technique. Monochromatic light at the wavelength 543 millimicrons was found to be the sole peak of stimulation to this insect in the visible spectrum. Beetles displayed a positive photic response by walking toward the source of light. A decrease in sensitivity occurred on either side of this peak, and in the longer wavelengths the sensitivity to light diminished at 735 millimicrons. Evidence to date indicated a second peak of sensitivity in the ultraviolet region of the spectrum; the latter appearing to be much greater than the peak in the visible spectrum. The intensity of any wavelength was also found to be a limiting factor in affecting beetle response, although in the longer wavelengths the sensitivity appeared to be a function of wavelength alone. Monochromatic light as a standard has been proposed for future bioassay techniques to act in opposition to odour stimuli. Red illumination was found to be effective in simulating darkness to T. lineatum. ‘Green’ unattractive sapwood shavings of Douglas-fir after placement under oxygen deficient conditions became attractive to T. lineatum. Maximum attractiveness was indicated in wood placed under anaerobiosis for 20 to 26 hours. Beyond 30 hours, little sign of attractants was noted. Control wood series did not undergo any transition, this leading to the conclusion that a significant change occurred in wood as a result of the anaerobic treatment. The implications of this result have been discussed. The successful use of wood shavings has made possible further studies on the nature of origin of attractants. The use of the anemotactic behaviour of beetles of both sexes to an airstream carrying host odour was found to be a highly efficient technique of analysis. The role of greater quantities of light in attracting insects away from a source of olfactory stimulation became increasingly apparent from this study. Moisture loss of the insect apparently did not alter their response to white light. / Science, Faculty of / Zoology, Department of / Graduate

A lengthy, and at times heated, debate on the regulation of animal numbers has proceeded in the literature for over half a century. A wide variety of causal agents - from sun spots to a shortage of trace elements - has been proposed to explain the observed densities, and a wide variety of mechanisms has also been proposed - from natural selection to chance. Only occasionally have any of these proposals been rigorously tested, and the survival of partially or totally conflicting hypotheses has been correspondingly high. I have attempted to test just one of these proposals: the polymorphism hypothesis of Chitty (Proc. Ecol. Soc. Australia 2:51-78, 1967.) According to this hypothesis, any natural population which lives in a highly favourable habitat can regulate its numbers through the action of two morphs, one characterized by a high fecundity and the other by a superior ability to hold its position in the environment. Population density is postulated to be a function of the relative frequency of the morphs and to change in a predictable way. I have conducted five experiments to investigate the existence of, and the mode of interaction between, these presumed morphs in Tribolium confusum, the questions asked being: 1) Is the density achieved by open populations (i.e. those from which emigration is allowed) different from that in closed populations (i.e. those from which emigration is prevented)? 2) Is the mechanism of regulation in open populations different from that in closed populations? 3) Is the tendency to migrate a constant property of individuals? 4) Is the density achieved by populations founded by migrants different from that of populations founded by non-migrants? 5) Is the density achieved by open populations (with migration by self-selection) different from that achieved by closed populations from which an equal number of animals are removed at random? I found the answers to all these questions to be 'yes', and the differences in each case to be in the direction predicted by the polymorphism hypothesis. I suggest that the polymorphism hypothesis is useful for predicting future densities of populations from which emigration is occurring, but is not useful for predicting densities in populations 1) from which animals cannot escape or 2) in which mortality caused by extrinsic factors is so great that, despite high fecundity, the populations are unable to produce a migrating surplus. I argue that 1) and 2) are rare in nature, or at least have been studied rather seldom. / Science, Faculty of / Zoology, Department of / Graduate

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