Annual Reproductive Cycle and Size at First Sexual Maturity of the Sun and Moon ScallopAmusium Japonlcum Japonicum(Gmelin, 1791) (Bivalvia: Pectinidae) in the Coastal Waters of Jejudo, Korea

Malacologia ◽  
2009 ◽  
Vol 51 (1) ◽  
pp. 119-129 ◽  
Author(s):  
Pal-Won Son ◽  
Ee-Yung Chung
Keyword(s):  
Reproductive Cycle ◽  
Coastal Waters ◽  
Sexual Maturity ◽  
The Sun ◽  
Annual Reproductive Cycle

Reproduction in the Indian mouse-tailed bat, Rhinopoma hardwickei hardwickei (Chiroptera, Rhinopomatidae)

1989 ◽  
Vol 1 (3) ◽  
pp. 255 ◽  
Author(s):  
KB Karim ◽  
S Banerjee
Keyword(s):  
Reproductive Cycle ◽  
Sexual Maturity ◽  
Uttar Pradesh ◽  
Gestation Period ◽  
Equal Frequency ◽  
Annual Reproductive Cycle ◽  
Males And Females

At and near Agra, in Uttar Pradesh, India, R. h. hardwickei had a strictly defined annual reproductive cycle. Although many females were inseminated during late February to mid April, ovulation was not recorded until 11 March. Progressively more females ovulated and conceived during the following weeks until the end of April and released one ovum from either of the ovaries with nearly equal frequency. A single conceptus was carried in the ipsilateral uterine cornu during each cycle. The gestation period was 95-100 days. Births occurred between the second week of June and the end of July. Lactation lasted at least 20 days. Females attained sexual maturity at an age of 8.5-9.0 months. Males took at least 16-17 months to attain sexual maturity. Females were segregated during lactation; during the rest of the year, males and females lived together.

Reproduction and embryonic development of the blue stingray, Dasyatis chrysonota, in southern African waters

2008 ◽  
Vol 89 (4) ◽  
pp. 809-815 ◽  
Author(s):  
David A. Ebert ◽  
Paul D. Cowley
Keyword(s):  
Life History ◽  
Reproductive Cycle ◽  
Coastal Waters ◽  
Management Strategy ◽  
Eastern Cape Province ◽  
Eastern Cape ◽  
Annual Reproductive Cycle ◽  
Life History Characteristics ◽  
Disc Width ◽  
Over Exploitation

Dasyatis chrysonota is perhaps the most common of the 14 whiptail stingray (Chondrichthyes: Dasyatidae) species known to frequent the temperate coastal waters of southern Africa and like other stingrays they possess life history characteristics that make them vulnerable to over-exploitation. First and 50% maturity (Dw50) were determined for 153 males and 204 females from the Eastern Cape Province of South Africa. Disc width (Dw) for first and Dw50 maturity was estimated at 392 mm and 395 mm Dw, respectively for males and at 500 mm and 505 mm Dw, respectively for females. The reproductive cycle of males, based on gonadosomatic (GSI) and hepatosomoatic (HSI) indices indicates that they are most active during the spring. Females appear to have an annual reproductive cycle with a maximum HSI occurring during the summer and autumn, but it declines steadily through the birthing season reaching a low in the late spring. Fecundity, following a nine month gestation period, averages 2.8 with a range of 1–7. Embryos at six different development stages are described. Dasyatis chrysonota, like other dasyatids, exhibit life history characteristics that make them vulnerable to overexploitation, therefore a precautionary management strategy is advised for this species.

scholarly journals Relationship between Body Length and Sexual Maturity, and Annual Reproductive Cycle in Male Mongoose(Herpestes javanicus)on Okinawa Island

2000 ◽  
Vol 5 (2) ◽  
pp. 141-148 ◽  
Author(s):  
Go OGURA ◽  
Yumi NONAKA ◽  
Yoshitsugu KAWASHIMA ◽  
Mitsuhiro SAKASHITA ◽  
Manabu NAKACHI ◽  
...  
Keyword(s):  
Body Length ◽  
Reproductive Cycle ◽  
Sexual Maturity ◽  
Annual Reproductive Cycle ◽  
Okinawa Island ◽  
Herpestes Javanicus

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.

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