151 |
Fitness and Physiology of the Hemlock Woolly Adelgid, Adelges tsugae, in Relation to the Health of the Eastern Hemlock, Tsuga canadensisJones, Anne 31 December 2013 (has links)
The hemlock woolly adelgid (HWA), Adelges tsugae Annand (Hemiptera: Sternorrhyncha: Adelgidae) is a small invasive insect that frequently causes hemlock (Tsugae spp.) mortality in the eastern United States. Studies have shown that once healthy hemlocks become infested by the adelgid, nutrients are depleted from the tree, leading to both tree decline and a reduction of the adelgid population. Since A. tsugae is dependent on hemlock for nutrients, feeding on trees in poor health may affect the insect's ability to obtain necessary nutrients and consequently affect their population and physiological health. A cluster analysis, based on quantitative and qualitative tree health measurements, grouped sample trees into categories of lightly and moderately impacted trees. The A. tsugae population health on each tree was determined by measuring insect density, survival from aestivation, and peak fecundity. A. tsugae physiological health was determined similarly by measuring insect biomass, total carbon, carbohydrate, total nitrogen, and amino nitrogen. A. tsugae from moderately impacted trees exhibited significantly greater fecundity; however, A. tsugae from lightly impacted hemlocks contained significantly greater levels of carbohydrates, total nitrogen, and amino nitrogen. All A. tsugae physiological parameters increased significantly over time as the insects matured and reproduced regardless of tree health classification. While the results of the physiological analysis generally support our hypothesis that A. tsugae on lightly impacted trees are healthier than those on moderately impacted trees, this was not reflected in the population fitness measurements of the insects. Further examination of A. tsugae egg health may elucidate this apparent contradiction. / Master of Science in Life Sciences
|
152 |
Biological differences between two geographically isolated, insecticide-susceptible, house fly (Musca domestica L.) populationsKnapp, Fred William. January 1958 (has links)
Call number: LD2668 .T4 1958 K67 / Master of Science
|
153 |
THE REPELLENT EFFECT OF PYRETHROID INSECTICIDES ON HONEY BEES (APIS MELLIFERA L, PERMETHRIN, CYPERMETHRIN, FENVALERATE).RIETH, JOSEPH PAUL. January 1986 (has links)
A model for the repellent effect of pyrethroid insecticides on insects was developed. Experiments were conducted using a small colony of honey bees in a flight cage. Conditioning to scented feeders allowed the separation of foraging bees from a single colony into treatment and control groups. Permethrin, cypermethrin, fenvalerate and flucythrinate were shown to be contact repellents to honey bees; exposure was primarily to the tarsi and ventral abdomen. The threshold dose of permethrin required to induce repellency was ca. 3.8 ng/bee. Repellency was fully reversible within 24 hours. No permanent effects on either memory or foraging efficiency were observed following acute exposure.
|
154 |
Pheromone trap interaction and dose-response experiments with Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae)Downham, Mark Crispin Anthony January 1999 (has links)
No description available.
|
155 |
Host plant effects on an aphid-bacterial symbiosisAdams, Diane January 1996 (has links)
No description available.
|
156 |
Cross-bridge structure and kinetics of insect fibrillar flight muscleKyrtatas, V. January 1987 (has links)
No description available.
|
157 |
Role of the flavonoids in the natural resistance of soyabean to Heliothis virescens (F.) and Trochoplusia ni (Huebner)Campo, Clara Beatriz Hoffmann January 1995 (has links)
No description available.
|
158 |
The effect of temperature on invasion and pathogencity of entomopathogenic nematodes (nematoda: Rhabditida) to larvae of Galleria mellonella and Otiorhynchus sulcatusSchirocki, Anke Gabriele January 1996 (has links)
No description available.
|
159 |
Studies on the sterile male technique for the control of the tropical warehouse moth, Ephestia cautellaMakee, H. January 1989 (has links)
No description available.
|
160 |
The biology of the fungi Tolypocladium cylindrosporum and Culicinomyces clavisporus in mosquitosMatawele, P. O. B. January 1986 (has links)
No description available.
|
Page generated in 0.0513 seconds