The annual reproductive cycle of the black prickleback, Xiphister atropurpureus, a Pacific Coast blennioid fish

1974 ◽  
Vol 52 (7) ◽  
pp. 795-802 ◽  
Author(s):  
John P. Wourms ◽  
David Evans
Keyword(s):  
Reproductive Cycle ◽  
Egg Size ◽  
Gonad Index ◽  
Egg Mass ◽  
Base Line ◽  
Annual Reproductive Cycle ◽  
Intertidal Habitat ◽  
Spawning Period ◽  
Egg Number ◽  
Xiphister Atropurpureus

Semimonthly determinations of the gonad index made during the course of a year show that Xiphister atropurpureus has an annual reproductive cycle. The gonad index (ovary) increases during midwinter, attains a maximum value of 20 in late April–May, and declines to a base-line value of 0.5 from June to December. Spawning occurs during a 6-week period in late April–May. Spawning takes place in zone 4 of the intertidal habitat. Eggs deposited singly are fertilized and then shaped into a spherical mass by the parents. As egg envelopes harden, they adhere to one another to form a coherent mass. The egg mass is guarded by one or both parents. The annual reproductive cycle is considered to be a necessary consequence of the energetic demands of oogenesis combined with selection for a spawning period which is environmentally optimal. Alternative cycles based on modification of the present egg size (large)/egg number (few) relationship do not appear feasible, since the required modification of the egg size/egg number ratio would be selectively disadvantageous. The intertidal habitat of Xiphisier is subject to several potential environmental hazards: wave shock, reduced salinity due to rain and runoff, and excessively high or low temperatures. These are seasonal hazards which occur during winter or summer. Spawning is timed (April–May), so the probability that developing eggs will be exposed to environmental risks is minimized while the probability of exposure to environmental benefits is maximized. It is suggested that the reproductive cycle is under photoperiodic control.

scholarly journals Reproductive cycle of Mellita quinquiesperforata (Leske) (Echinodermata, Echinoidea) in two contrasting beach environments

2006 ◽  
Vol 23 (2) ◽  
pp. 573-580 ◽  
Author(s):  
Yara A. G. Tavares ◽  
Carlos A. Borzone
Keyword(s):  
Reproductive Cycle ◽  
Gonad Index ◽  
Storage Period ◽  
Reproductive Period ◽  
Population Characteristics ◽  
Adaptive Plasticity ◽  
Allocation Of Resources ◽  
Oocyte Size ◽  
Nutrient Storage ◽  
Spawning Period

The reproductive cycle of the irregular echinoid Mellita quinquiesperforata (Leske, 1778) was studied in populations from two sand beaches with different morphodynamic conditions in Parana coast, from February 1992 through July 1994. Gametogenesis was described by histological and gonad index methods and the differences between both populations were observed in the extension of nutrient storage and spawning period. Both populations exhibited a main reproductive period during spring/summer and a nutrient storage period during autumn/winter months. The spawning period at the intermediate-dissipative beach was shorter than at the reflective beach. Meanwhile, a nutrient storage stage was more extensive in the latter. Gonad index varied between both sexes and it was influenced by population characteristics. Different strategies in allocation of resources between maintenance and reproduction effort (oocyte size) confirm the high adaptive plasticity developed by this species to live in contrasting beach environments.

scholarly journals Sexually dimorphic transcription of estrogen receptors in cod gonads throughout a reproductive cycle

2014 ◽  
Vol 52 (3) ◽  
pp. 357-371 ◽  
Author(s):  
Kazue Nagasawa ◽  
Christopher Presslauer ◽  
Lech Kirtiklis ◽  
Igor Babiak ◽  
Jorge M O Fernandes
Keyword(s):  
Estrogen Receptors ◽  
Somatic Cell ◽  
Reproductive Cycle ◽  
Atlantic Cod ◽  
Sexually Dimorphic ◽  
Annual Reproductive Cycle ◽  
Follicular Cells ◽  
Spawning Period ◽  
Sexually Dimorphic Expression ◽  
Dimorphic Expression

The role of sex steroid regulation in gonadal maturation is a very complex process that is far from being fully understood. Hence, we have investigated seasonal changes in gonadal expression of estrogen receptors (ERs) in Atlantic cod (Gadus morhua L.), a batch spawner, throughout the annual reproductive cycle. Three nuclear ER partial cDNA sequences (esr1, esr2a, and esr2b) were cloned and all esr transcripts were detected mainly in liver and gonads of fish of both sexes. In situ hybridization of esrs along with germ cell (vasa) and gonadal somatic cell markers (gonadal soma-derived factor (gsdf), 3β-hydroxysteroid dehydrogenase (3βhsd), and anti-Müllerian hormone (amh) for testicular, or gsdf for ovarian somatic cells) showed that all three esrs were preferentially localized within interstitial fibroblasts composed of immature and mature Leydig cells in testis, whereas they were differentially expressed in both follicular cells and oocytes in ovary. Quantitative real-time PCR analysis revealed a sexually dimorphic expression pattern of the three esr paralogs in testis and ovary. A significant increase in esr2a expression was identified in testis and of esr2b in ovary, whereas esr1 transcripts were elevated in both testis and ovary in February and March before the spawning period. The localization and sexually dimorphic expression of esr genes in gonads indicate a direct function of estrogen via ERs in gonadal somatic cell growth and differentiation for Leydig cell in testis and follicular cells in ovary throughout the annual reproductive cycle in Atlantic cod.

INFLUENCE OF NATURAL DIETS AND LARVAL DENSITY ON GYPSY MOTH, LYMANTRIA DISPAR (LEPIDOPTERA: ORGYIIDAE), EGG MASS CHARACTERISTICS

1977 ◽  
Vol 109 (10) ◽  
pp. 1313-1318 ◽  
Author(s):  
John L. Capinera ◽  
Pedro Barbosa
Keyword(s):  
Gypsy Moth ◽  
Egg Size ◽  
Larval Density ◽  
Field Studies ◽  
Forest Composition ◽  
Egg Mass ◽  
Natural Diet ◽  
Egg Masses ◽  
Egg Number ◽  
Host Tree Species

AbstractLaboratory and field studies indicate that differences in gypsy moth egg mass characteristics can be related to larval density and natural diet. Egg mass characteristics are valuable indices of population quality as well as future population levels. Laboratory crowding reduced number of eggs/mass but did not affect egg size. Field collected egg masses from various population levels in Massachusetts also varied in egg number/mass, but egg size could not be directly correlated to density. Laboratory rearing of larvae on several natural diets produced differences in both egg number and size. Maple diets produced egg masses with fewer, smaller eggs, as compared with oak diets. Field collected egg masses also varied in mean egg size, according to host tree species. Thus, forest composition may directly affect the quality of gypsy moth populations, as well as numerical levels. Increasing density could affect egg size indirectly, by forcing gypsy moth larvae to feed on unfavorable host foliage.

Mechanisms underlying pituitary microvascular remodelling in thoroughbred horses during the annual reproductive cycle

2014 ◽  
Author(s):  
Angus Yeomans ◽  
Nichol Thompson ◽  
Jennifer Castle-Miller ◽  
David O Bates ◽  
Domingo Tortonese
Keyword(s):  
Reproductive Cycle ◽  
Annual Reproductive Cycle ◽  
Thoroughbred Horses

scholarly journals Proliferative and Apoptotic Pathways in the Testis of Quail Coturnix coturnix during the Seasonal Reproductive Cycle

Animals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1729
Author(s):  
Sara Falvo ◽  
Luigi Rosati ◽  
Maria Maddalena Di Fiore ◽  
Federica Di Giacomo Russo ◽  
Gabriella Chieffi Baccari ◽  
...  
Keyword(s):  
Reproductive Cycle ◽  
Second Messengers ◽  
Reproductive Period ◽  
Annual Reproductive Cycle ◽  
Coturnix Coturnix ◽  
Immunohistochemistry Analysis ◽  
17Β Estradiol ◽  
Apoptotic Pathways ◽  
Camp And Cgmp ◽  
Activation Phase

The quail Coturnix coturnix is a seasonal breeding species, with the annual reproductive cycle of its testes comprising an activation phase and a regression phase. Our previous results have proven that the testicular levels of both 17β-estradiol (E2) and androgens are higher during the reproductive period compared to the non-reproductive period, which led us to hypothesize that estrogens and androgens may act synergistically to initiate spermatogenesis. The present study was, therefore, aimed to investigate the estrogen responsive system in quail testis in relation to the reproduction seasonality, with a focus on the molecular pathways elicited in both active and regressive quail testes. Western blotting and immunohistochemistry analysis revealed that the expression of ERα, which is the predominant form of estrogen receptors in quail testis, was correlated with E2 concentration, suggesting that increased levels of E2-induced ERα could play a key role in the resumption of spermatogenesis during the reproductive period, when both PCNA and SYCP3, the mitotic and meiotic markers, respectively, were also increased. In the reproductive period we also found the activation of the ERK1/2 and Akt-1 kinase pathways and an increase in second messengers cAMP and cGMP levels. In the non-reproductive phase, when the E2/ERα levels were low, the inactivation of ERK1/2 and Akt-1 pathways favored apoptotic events due to an increase in the levels of Bax and cytochrome C, with a consequent regression of the gonad.

Interpopulation variability of the reproductive cycle of Paracentrotus lividus (Echinodermata: Echinoidea) in the south-western Mediterranean

2000 ◽  
Vol 80 (5) ◽  
pp. 899-907 ◽  
Author(s):  
Mourad Guettaf ◽  
Gustavo A. San Martin ◽  
Patrice Francour
Keyword(s):  
Regional Scale ◽  
Gonad Index ◽  
Paracentrotus Lividus ◽  
Posidonia Oceanica ◽  
Western Mediterranean ◽  
Larval Phase ◽  
Spawning Period ◽  
Rocky Substrate ◽  
Maximum Value ◽  
Reproductive Cycles

The spawning of Paracentrotus lividus has been determined on the basis of the annual gonad index cycle at three sites in the Algiers area presenting low, intermediate and strong hydrodynamism. Three biotopes (Posidonia oceanica beds, rocky substrate with photophilous algae and overgrazed rocky substrate) and two depths (1–3 m and 6–10 m) were considered at these sites, the sex-ratio was always strongly in favour of females (2:1 to 3:1). In all sites but one, there were marked differences in the gonad index and the spawning period between sites; the gonad index reached its maximum value at the site with the weakest hydrodynamism, and the minimum value at the site with the strongest hydrodynamism. Spawning took place in April–May and August–September at the site with the weakest hydrodynamism, in April–June and October–December at the site with intermediate hydrodynamism and only in winter at the site with maximum hydrodynamism. The coexistence, on regional scale, of these reproductive cycles might enable Paracentrotus lividus to compensate the mortality during planktonic larval phase by the fact that spawning of this sea urchin occurred in all seasons.

Fecundity of Resident and Anadromous Dolly Varden (Salvelinus malma) in Southeastern Alaska

1973 ◽  
Vol 30 (4) ◽  
pp. 543-548 ◽  
Author(s):  
R. F. Blackett
Keyword(s):  
Egg Size ◽  
Fish Length ◽  
Dolly Varden ◽  
Salvelinus Malma ◽  
Ovary Weight ◽  
Dolly Varden Salvelinus Malma ◽  
Egg Number ◽  
Unit Of Length ◽  
The Right ◽  
Linear Regressions

Fecundity of resident Dolly Varden (Salvelinus malma) in an isolated population of southeastern Alaska averaged 66 eggs per female in comparison with 1888 eggs for anadromous Dolly Varden from two nearby streams. A relatively large egg size, averaging 3.6 mm in diameter and overlapping the range for the anadromous char, has been retained by the females in the resident population. Curvilinear regressions between egg number and fish length and linear regressions between egg number and body and ovary weights show that resident females have fewer eggs per unit of length, approximately the same number of eggs per gram of body weight, and more eggs per gram of ovary weight than anadromous females. The resident char attain sexual maturity a year earlier in life and at a smaller size than the migratory char. Development of a larger left ovary containing more eggs than the right was a common occurrence for both resident and anadromous Dolly Varden.

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