Treatment of gonadectomized adult male and female sticklebacks as well as normal juvenile, with methyl testosterone, either by immersion in a hormone solution or by implanting hormone pellets, induces the kidney cells to develop into granular and mucous cells, accompanied by an increase in cell height. Increase in cell height, up to a limit, is a function of the length of hormone treatment. Prespawning aggressiveness and territoriality is induced in gonadectomized fish of both sexes by maintaining them under long photoperiod for four to five weeks. Short photoperiod has no effect. Administration of methyl testosterone to the already aggressive fish showed no definite effect on this behaviour. The combined effect of long photoperiod and methyl testosterone treatment induces the nest-building behaviour in gonadectomized males and females with a much higher percentage in the former than in the latter. The component elements of the nest-building movement in the treated gonadectomized male is similar qualitatively and quantitatively to that of the normal reproducing male. Treated gonadectomized females show deviations from the normal male in their nest-building movements. Sexual behaviour is the same in castrates treated with methyl testosterone as in the normal reproducing male, but completely absent in the similarly treated gonadectomized females. / Science, Faculty of / Zoology, Department of / Graduate

Fecundity data were obtained for twelve species of British Columbia freshwater fishes by use of a displacement method. Data for an additional fourteen species were obtained from the literature. Fecundity relative to a unit body weight was considered superior to absolute fecundity for use in racial studies. Egg diameter was significantly larger in anterior than in posterior regions of ovaries from five species tested. Egg diameter was positively correlated with fork length within and between species. Amongst twenty-six freshwater species considered, egg diameter was found significantly correlated with reproductive characteristics. Fish with eggs of large mean diameter generally have amber to salmon colored eggs, non-adhesive eggs, long incubation periods, redd construction, stream spawning and variable spawning season. Fish with eggs of small mean diameter have white to yellow eggs, adhesive eggs, short incubation period, lack of redd construction, variable spawning location and spring or summer spawning season. / Science, Faculty of / Zoology, Department of / Graduate

Experimental components analysis (Holling 1966) is used to develop a computer model of the four processes of sexual reproduction: mating, egg production, egg fertilization, and oviposition site selection. A general function of interacting populations is developed, and its application to mating and oviposition site selection is discussed. Data from the literature on mating are used to estimate parameter values for this function. A model of egg production and egg fertilization is developed from an experimental study of the vg strain of Drosophila melanogaster. Egg production is a complex process consisting of four components affecting individual ovarioles: ovariole activation, ovariole production, vitellegenesis, and ovariole deactivation. Threshold effects are found to exist for all four components. Egg fertilization is a simple process involving number of sperm stored and a constant probability of successful fertilization. However, results indicate that both egg fertilization and egg production become more complex beyond the range of treatments used here. Assumptions, not supported by data, are made for the processes of oviposition site selection, aging, mortality, and development. These assumptions are combined with the models of mating, egg production, and egg fertilization into a single tentative model for sexual reproduction. Simulations using this model suggest possible effects of ecological importance: a sigmoid relationship between reproductive rate and density; and a chance in tactics with increasing mortality due to predation. / Science, Faculty of / Zoology, Department of / Graduate

The natural cycle of reproduction in Cymatogaster aggregata Gibbons, a viviparous teleost, has been described and investigated experimentally. Laboratory manipulations of photo-period and temperature show that both are concerned with the environmental regulation of the cycle. The role of the pituitary was studied by the use of Methallibure, a chemical inhibitor of pituitary gonadotropic function. 3β— and 17β- hydroxysteroid dehydrogenases were localized in the gonads by histochemical tests and testicular steroids were partly identified biochemically. The role of androgens was studied with gonadectomized specimens and steroid replacement therapy. These various techniques indicate that increasing daylength in March and April stimulates production and/or release of pituitary gonadotropins and that the gonadotropins in turn initiate spermatogenesis and stimulate interstitial Leydig cells. The warm temperature of intertidal waters in addition to the long period of daily illumination from May to July accelerate spermatogenesis and testicular steroidogenesis. Increased gonadal androgen production, in turn, results in a modification of the male anal fin and brings on a full display of reproductive behaviour; some of the behaviour sequence, however, is controlled by pituitary gonadotropins. Restitution of the testes occurs in fall and winter. Oocyte formation appears to be enhanced by a lowered titre of gonadotropic hormones resulting from the warm temperatures of July and August. On the other hand, oocyte maturation in late autumn and early winter and gestation during early pregnancy require pituitary gonadotropins. / Science, Faculty of / Zoology, Department of / Graduate

Gross and histological analyses of reproductive tracts from multiparous, nulliparous, and non-pregnant females of Pribilof Islands (eastern Pacific) origin have been used to determine the histology and physiology of the estrus cycle, the age of sexual maturity, and certain causes of prenatal mortality. The ovaries alternate in function, one ovary ovulating in one breeding season, the opposite ovary ovulating in the next. An undetermined factor suppresses follicular development in the ovary containing a corpus luteum of pregnancy; suppression maintains for 6 months after parturition. Graafian follicular development is greatest in July, with an average 15 follicles in the ovary destined to ovulate. About 4 of these will enlarge abruptly prior to ovulation; one will reach ovulation size (10 mm or greater in diameter) and rupture; the rest will become atretic. Mating occurs 3-5 days after parturition in mid-July. If fertilization is accomplished, the resulting blastocyst remains free in the uterus until early or mid-November, when it implants in the mucosa. The newly formed corpus luteum is actively secretory for a month after ovulation. During this time, follicular development is suppressed in both1 ovaries, and the uterine mucosa is progesteronic. From the end of August, the corpus luteum is regressive; the luteal cells are vacuolated, and secretion is minimal. This is reflected in a recrudescence of follicular activity in the ovary containing the corpus luteum, and regression of the associated uterine mucosa. Immediately prior to implantation the corpus luteum resumes secretion, and the mucosa is prepared for implantation. Placentation is established during December. Luteal degeneration begins in January and is progressive until parturition, when the corpus luteum appears to be non-secretory. Luteal degeneration has no affect on the pregnant uterine horn; it is assumed that the placenta secretes sufficient hormone to replace the luteal hormones. Prenatal mortalities take 3 forms: "missed” pregnancies, abortions, and resorptions. On the basis of histological examinations, "missed" pregnancies are ultimately due to failure of implantation. Three conditions are responsible: failure of fertilization, failure of implantation, or malfunction of the reproductive tract which precludes pregnancy. Abortion results in the expulsion of a conceptus from the uterus before term; resorption is a gradual process of dissolution of the conceptus within the uterus. On the basis of histological evidence, three causative agents of abortion and resorption are evident: degeneration of the corpus luteum after implantation, malfunction of the uterine mucosa, and intra-uterine mortality of the conceptus. Annovulatory cycles, dominated by Follicle Stimulating Hormone, occur among females 1 to 3 years of age. A cycle increasingly dominated by Luteinizing Hormone and culminating in ovulation occurs among the majority of 4-year-old females. The follicular cycle resulting in the first ovulation is later than subsequent cycles; the peak of first ovulations occurs around August 25th. On the basis of gross examinations, 60% of females ovulate for the first time at 4 years of age. Since the pregnancy rates of 5-year-old females are consistently about 50%, probably a number of 4-year-olds do not mate, either because ovulation occurs after the breeding season, or because breeding males are not available. Gross and histological analyses of reproductive tracts from nulliparous females of Robben and Commander Islands (western Pacific) origin have been used to compare the reproductive potential of two breeding populations of fur seals,; Pregnancy rates among females 4 years of age of Robben and Commander Islands origin are approximately 50%; those of 4-year old-females of Pribilof Islands origin are approximately 5%. The disparity in the age of reproductive maturity between females of the two populations is based on a physiological delay of one year in the maturation of the endocrine system controlling reproduction among females of Pribilof Islands origin. / Science, Faculty of / Zoology, Department of / Graduate

The object of this study was to compare the role of changes in reproduction and mortality in regulating population density in the deer mouse, Peromyscus maniculatus, and if possible to discover some of the factors affecting the reproductive rate. Observations were made on natural and experimentally reduced populations on the University Endowment Lands in 1964 and 1965. In both years numbers remained relatively steady during the summer, increased in the fall, when immature animals replaced the adults, and gradually declined over the winter. Animals were about equally abundant at comparable times in both years, fall densities being about 4.72 mice per acre. The stationary state of these populations was associated with a poor reproductive performance on the part of the females, whose breeding success varied between areas, and was greater in 1964 than in 1965. No change in litter size or in prenatal loss was observed during the period of study. The males, in contrast, were sexually active from March to September on all areas in both years. The greatest loss of mice occurred between birth and age at first capture, after which juveniles survived at the same rate as the adults. Survival was poorer during the breeding season than during the winter, and survival of males was poorer than that of females. Populations whose numbers had. been experimentally reduced and whose age structure had been altered, were not significantly different from the natural populations in mean monthly body weights, reproductive performance, or survival. Mean monthly body weights and reproductive performance were lower, and survival of the young from birth to age at first capture was higher in 1965 than in 1964. The proportion of subadults which became fecund was greatest on this area in 1964. The stationary state of these populations was maintained by changes in survival rather than by changes in reproductive rate. The reproductive performance of the females was fairly constant whereas the loss of young from birth to age at first capture varied. Loss of the young is attributed to their death or emigration in response to aggressive interactions within the population. / Science, Faculty of / Zoology, Department of / Graduate

Microsporogenesis, embryo sac development Including fertilization, and fruit set involving cross pollinations were studied in the highly self-fertile red raspberry (Rubus idaeus L.) cultivar Mailing Jewel and the partially male sterile United States Department of Agriculture -Oregon State University selection Ore-US 1314 from the United States Department of Agriculture-Oregon State University red raspberry breeding program. Pollen was stained with aceto-carmine to determine pollen abnormality. Anthers of different filament lengths differed in the percent of normal pollen produced in the Ore-US 1314. Percent normal pollen produced by this selection is also much less than that, produced by Mailing Jewel. Longitudinal and cross sections of the anthers of both clones were examined and no direct involvement of the tapetum was observed to be contributing to the production of abnormal microspores in either clone. Anther squashes showed that only 41.8% of the cells of Ore-US 1314 underwent normal meiosis as compared to 93% in Mailing Jewel. Lagging chromosomes at meiosis I were also observed in Ore-US 1314. Cytogenetic factors are thought to be involved in causing increased pollen abortion and thus male sterility in Ore-US 1314. Examinations of embryo sac development under open pollination showed that while Ore-US 1314 did riot have a retarded embryo sac development, it had a high percentage of degenerate embryo sacs. Degeneration is believed to be a result of pollen of poor quality, incompatible pollen, the collapse of the egg cell due to failure of pollen to fertilize it at the critical time, or the involvement of all three. The pollination experiments involved self, open, and cross-pollinations of the two clones. The results obtained from the druplet set suggest that Ore-US 1314 could be both partial and cross-incompatible. Druplet set in Ore-US 1314 when open pollinated increased above that when selfed suggesting a positive reaction to pollen mixtures. Mailing Jewel, although not self-incompatible, was found to be partially cross-incompatible with Ore-US 1314. / Land and Food Systems, Faculty of / Graduate

Four plant communities of southwestern British Columbia were studied in an attempt to answer the following related questions: (1) do communities of harsh physical environments exhibit any characteristic phytosociological features? (2) are there any correlations between environmental harshness and certain synecological properties of such communities ? (3) are species of such communities selected for reproductive specializations that tend to reduce their genetic variability? The four communities (representing three types of herbaceous or semi-shrubby vegetation) were a salt marsh, two coastal sphagnum bogs, and a subalpine meadow. In answer to the first two questions, the findings of this investigation indicate that: (a) species population structure becomes more aggregated as environmental heterogeneity and physical stress increase, and less aggregated as succession proceeds and interspecific competition increases. (b) interspecific association and correlation, both negative and positive, increase as environmental heterogeneity and competition increase. (c) levels of polyploidy within communities appear to be correlated with environmental rigor (broadly defined). (d) the most abundant species within a community are the most variable and presumably have the largest niches ; niche size and population variability decrease as interspecific competition increases. (e) within a community, ecological distinctiveness reduces interspecific competition; communities under the least stress (especially seasonal stress) have the most ecologically dissimilar1 species. (f) dominance decreases as species diversity increases, and species diversity is roughly correlated with overall environmental severity. In answer to the last question: (a) all four communities are dominated by predominantly outcrossing species; there is no major shift to self-pollination or apomixis in any of the communities. (b) an index of potential recombination was devised, embodying a number of aspects of reproductive biology, according to which there is no significant difference in potential recombination, on the average, between species of the four different communities. Plant communities and their constituent species both respond to evolutionary forces, but more or less independently, at different rates, and often in different or even opposite ways. Environmental stress has a powerful effect on the structure and function of plant communities, but in an evolutionary sense there is little difference between normal (mesic, zonal) environments and extreme or azonal environments to an individual species. Different selection pressures have been operating in salt marshes, sphagnum bogs, and subalpine meadows, but the present study indicates that, on the average, the resultant evolutionary strategies of the species of these communities are equivalent. / Science, Faculty of / Botany, Department of / Graduate

The objective of this study was to determine the involvement of prostaglandins in the sexual development of both male and female goldfish. Carassius auratus. A chromatographic method was developed to separate the different prostaglandin groups. To standardize the procedure, extraction and separation recoveries were measured using tritiated-prostaglandins. Radioimmunoassay was used to measure the PGB1, PGE1 and PGF2* in the plasma and gonad. Initially, a seasonal study was undertaken to assess the importance of prostaglandins during sexual maturation. Samples of plasma and gonad were assayed monthly for prostaglandins (from December to March) from two groups of fish, one held under natural photoperiod and the other under long photoperiod (16L:8D). Although monthly variations occurred in all three prostaglandins examined, these changes did not correlate with changes in gonadal maturationi Prostaglandins were then measured in serial plasma samples of non-gravid and ovulating female goldfish. Ovulation was induced in gravid fish by increasing the water temperature from 14° C to 20° C and by injecting human chorionic gonadotropin (HCG) . It was found that: 1) PGF2 increased over 14 fold, 12 hours after the onset of ovulation (from pre-injection levels of 300 pg/ml to more than 4,000 pg/ml); however, this increase appeared to commence immediately after ovulation. There was no change in plasma P1GF20< levels in non-gravid control fish. The concentration of PGF2^in the ovarian fluid was over 9,000 pg/ml. 2) PGE1 decreased almost three-fold between the time of HCG injection (an average of 10 hours before ovulation) and 24 hours later. The plasma PGE 1 levels in the non-gravid females were up to 20 times less than the gravid ovulating females. The concentration of PGE1 in the ovarian fluid was 630 pg/ml. 3) PGB1 levels decreased in the plasma of non-gravid and ovulating goldfish, following HCG injection. The ovarian fluid contained 300 pg/ml of PGB1. Parallel experiments were performed on male goldfish that were spermiating. There were no significant changes in plasma PGF20C within 24 hours of HCG injection, whereas PGB1 decreased slightly (as for the females), and PGE1 increased significantly 10 hours after HCG injection. The findings of this study suggest that PGF2 and PGE1 in the ovarian fluid are the agents controlling ovulation in the female goldfish and that corresponding levels in the blood contribute to other events associated with ovulation. The experiments on males indicate a possible role for PGE1 during spermiation; however, it is difficult to ascertain its precise involvement at present. / Science, Faculty of / Zoology, Department of / Unknown

Testes and paragonial glands of Drosophila melanogaster wild type males were labelled in vitro using ³⁵S-methionine, and the proteins synthesized were analysed by 2-dimensional gel electrophoresis (O'Farrell, 1975). Testes and paragonial glands were also labelled in vivo by feeding male or larvae on ³⁵S-labelled yeast and then dissecting the adult males. Approximately 1200 proteins were resolved by autoradiography of the gels. The in vitro method was shown to be more sensitive and to allow faithful synthesis of all proteins produced in vivo. ³H-proline was also used to label testes, and no significant differences from the pattern obtained with ³⁵S-methionme were found. Different laboratory stocks were analyzed to examine the degree of genetic heterozygosity of testicular proteins. The variation between patterns was very low, facilitating subsequent studies in which flies of defined genetic constitution, but with different genetic backgrounds, were compared. Testes and paragonial glands from X/0 and X/Y/Y males were labelled in vitro with ³⁵S-methionine, and the proteins synthesized were compared to those produced by wild-type males of identical autosomal background. No differences attributable to the Y chromosome could be detected in the testes or paragonial gland samples. Non-equilibrium pH gradient 2 dimensional gels (O'Farrell et al., 1977) were also run on testis proteins from X/0, X/Y and X/Y/Y males. These gels will resolve basic as well as acidic proteins and once again no differences attributable to the Y chromosome were seen. Pure sperm was manually dissected from in vivo labelled males and the proteins analyzed. Ninety-two proteins were detected, and all were synthesized in comparable amounts by X/0, X/Y and X/Y/Y males, showing that the Y chromosome does not code for any of these structural sperm proteins. It is postulated that no Y chromosome products were detected because they are organizational factors, or regulatory proteins only present in very small amounts in the adult testes. ³⁵S labelled males were also mated to unlabel led females, and the proteins of the transferred sperm were analyzed by 2DPAGE. The contributions of the testes and paragonial gland to the ejaculate were determined. Testes at various stages of development were also cultured in vitro in ³⁵S-methiomne containing media. A profile of the proteins synthesized during development revealed that the spectrum of proteins synthesized at different stages between third instar larvae and the imago were remarkably similar, despite the morphological changes taking place in the organ. Sperm proteins were localized on the patterns, and the quantitative changes occurring during this period were examined. The basic proteins of the testis were studied in an attempt to biochemically identify a Drosophila protamine. Sperm was isolated by dissection, and the acid soluble proteins were separated on a 15% modified Laemmli SDS gel. No unusually small basic protein was seen upon staining, but a protein was present which comigrated with trout histone H4. This suggests that D. melanogaster males may retain somatic histones in the nucleus during the condensation of the sperm head. Testes were labelled in vitro with ³H-arginine and the basic proteins were analyzed on a 15% modified Laemmli SDS gel. The gel was autoradiographed and a prominent doublet was seen at the front of the gel, suggesting that a small highly basic protein is synthesized in the testis. / Medicine, Faculty of / Biochemistry and Molecular Biology, Department of / Graduate