Aedes togoi (Theobald) from Vancouver, B.C. may enter diapause in either the egg or the larval stage. Larval diapause occurred in the 4th instar, when immatures were maintained at 16°C or less, at photoperiods shorter than 12h light/day. The critical photoperiod was calculated as LD 10.9:13.1 at 16°C. Larvae which did not pupate after 40 days at the experimental conditions were assessed as being in diapause. Non-diapause larvae reached the pupal stage in 17-20 days at 16°C. At 14°C, 100% of the larvae diapaused at LD 10:14. Temperatures of 18°C or higher, at LD 10:14, resulted in no larval diapause. Embryonic diapause resulted when immatures, adults and eggs were maintained at temperatures ranging from 22 to 28°C, at photoperiods shorter than 15h light/day. The critical photoperiod was calculated as LD 15.3:8.7 at 25°C, and LD 14.4:9.6 at 22°C. There was no diapause when the population was maintained at 24°C LD 16:8. An experiment was conducted to determine if a simulated dawn/dusk of 90 minutes/day would increase mating success. After three days at the experimental conditions, there was no difference in mating success between populations of males and females maintained with a dawn/dusk period and those maintained at the same photoperiod where the light/dark change was abrupt. / 1986

Berlin, Freie Univ., Diss., 1998. / Dateiformat: zip, Datei im PDF-Format

No description available.

Thesis (M.S.)--Miami University, Dept. of Zoology, 2007. / Title from first page of PDF document. Includes bibliographical references (p. 17-20).

These studies were conducted to determine the mechanisms by which prolactin (PRL) exerts its luteotropic effects on the mink corpus luteum (CL). Three experimental models were developed and utilized in these studies. In the first model, the ovaries from pregnant mink were collected at regular intervals throughout gestation, half the animals were treated with the dopamine agonist 2-bromo-$ alpha$-ergocryptine (bromocryptine), to suppress their endogenous PRL levels, and half were exposed to their endogenous PRL levels. The second model consisted of treating anestrous animals with exogenous gonadotropins to induce follicular development and ovulation, half the animals were then treated with PRL while the other half were left as untreated controls. In the third model, CL were collected from mink at several stages of mink gestation. The cells were enzymatically dispersed, placed in culture and incubated with different concentrations of PRL, luteinizing hormone (LH), follicle stimulating hormone (FSH) and (Bu)$ sb2$cAMP. Using these 3 models, the effects of PRL on P450 side chain cleavage (P450scc), 3$ beta$-hydroxysteroid dehydrogenase (3$ beta$-HSD), steroidogenic acute regulatory protein (StAR), luteinizing hormone receptor (LHr) and prolactin receptor (PRLr) mRNA were determined. Messenger RNA levels for P450scc did not vary significantly over the course of mink gestation and treatment of animals with bromocryptine did not alter the abundance. In the anestrous model, treatment of mink with PRL reduced P450scc mRNA levels below that of the untreated control, while treatment of cultured mink luteal cells with increasing concentrations of PRL had no effect on the abundance of P450scc mRNA. The abundance of 3$ beta$-HSD mRNA varied over the course of mink gestation. Levels were low during embryonic diapause, increased during CL reactivation and peaked during post-implantation gestation. Treatment of mink with bromocryptine prevented the pre-implantation rise in 3$ bet

Typescript. Includes vita and abstract. Includes bibliographical references (leaves 94-109) Also available online in Scholars' Bank; and in ProQuest, free to University of Oregon users.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1983. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1970. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

In this thesis I present complex experimental data on the physiological and molecular adaptations during diapause development and overwintering in a linden bug, Pyrrhocoris apterus (Heteroptera, Pyrrhocoridae). I focus on adjustments of the enzymatic complement, which is involved in the biosynthesis of cryoprotectants, and heat shock proteins, which are expressed in response to temperature stress.

No description available.