Ovarian activity was studied during the annual reproductive cycle and nesting cycle in the Indian pied myna (Sturnus contra contra). The investigation was carried out on the basis of gravimetric, histological (gross and quantitative), and histochemical (3β-hydroxysteroid dehydrogenase and lipids) studies. In the ovary of the pied myna, four types of healthy follicles (primordial, small developing, large developing, and yolky) were recognized; the stroma showed gland cells. Steroidogenic activity was marked in the theca and granulosa of the follicles, and it altered with the growth of the follicles. The probable source of stromal gland cells is discussed. The ovarian activity changed over the course of the year with four distinct phases, viz., progressive (February to April), breeding (May), regression (June to July), and nonbreeding (August to January) phases. Ovarian weight, largest follicular diameter, populations of larger follicles, and thecal gland cell mass increased gradually from February through April, became maximal in May, decreased in June and July, and became minimal during August through January. Yolky follicles developed only in May. Stromal gland cell mass was abundant in March, decreased from April to June, was almost absent from July to September, reappeared in October, and gradually increased afterwards. Steroidogenic activity of the thecal and stromal gland cells also changed with the annual ovarian cycle; it was absent during July through September and reappeared in October. The granulosa cells showed steroid activity only in May. During the nesting cycle, ovarian activity increased rapidly from early nest-building to egg-laying periods and declined during incubation and nestling periods; this was evident from changes in ovarian weight, largest follicular diameter, thecal gland mass, and populations of larger follicles. Yolky follicles were seen during late nest-building, egg-laying, and incubation periods. Stromal gland cell mass decreased gradually during the nesting cycle. 3β-Hydroxysteroid dehydogenase activity was maximal in the nest-building period.
Arthropod and Helminth Parasites from the Plains Pocket Gopher, Geomys bursarius bursarius from the Hosts' Northern Boundary Range in Minnesota
