Geographic and annual variation in reproductive cycles in the Tasmanian spotted snow skink, Niveoscincus ocellatus (Squamata : Scincidae)

1999 ◽  
Vol 47 (6) ◽  
pp. 539 ◽  
Author(s):  
Erik Wapstra ◽  
Roy Swain ◽  
Susan M. Jones ◽  
Julianne O'Reilly
Keyword(s):  
Reproductive Cycle ◽  
Annual Variation ◽  
Thermal Conditions ◽  
Gestation Length ◽  
Annual Reproductive Cycle ◽  
Climatic Range ◽  
Reproductive Cycles ◽  
Reproductive Events ◽  
Two Populations ◽  
Winter Hibernation

We studied the reproductive cycle of two populations of the spotted snow skink, Niveoscincus ocellatus, over a three-year period. This species is widespread in Tasmania and its distribution overlaps those of other species in the genus that show two distinct reproductive strategies: annual reproduction that is completed within one season, and biennial reproduction in which females carry advanced embryos throughout winter hibernation. We chose populations representative of the climatic extremes of the species’ distribution, within these areas of overlap. Niveoscincus ocellatus maintains the same basic reproductive strategy in both populations: summer gestation, primary autumn mating with obligate sperm storage by females, secondary mating in spring, and predominantly spring vitellogenesis and ovulation. In both populations all females reproduce annually, suggesting that reproductive frequency is not constrained by availability of energy. However, we found distinct differences in the timing of ovulation and parturition. Females from our subalpine site ovulated approximately one month later than those from our warmer, lowland site; parturition was delayed by the same period so gestation length was unchanged. The delay in ovulation results in gestation proceeding over the warmest months at the cold site. The annual reproductive cycle of this species appears to constrain its distribution to the lower altitudinal/climatic range of alpine Niveoscincus species. There were minor annual differences in the timing of reproductive events at each site, which we attribute to variation in thermal conditions and the amount of precipitation.

Control of the Reproductive Cycle in Female Eulalia Viridis (Polychaeta: Phyllodocidae)

1981 ◽  
Vol 61 (4) ◽  
pp. 941-958 ◽  
Author(s):  
P. J. W. Olive
Keyword(s):  
Reproductive Cycle ◽  
Marine Invertebrates ◽  
Individual Species ◽  
Temperature Cycle ◽  
Polychaete Species ◽  
Cellular Events ◽  
Back Ground ◽  
Reproductive Cycles ◽  
Reproductive Events ◽  
Abundant Data

Eulalia viridis (L.) is one of a group of polychaete species which are being used in an experimental analysis of the regulation of gametogenesis and reproduction. The back-ground to these studies and some of the preliminary results have been discussed recently by Olive (1980). Despite the abundant data demonstrating the frequent occurrence of well-defined reproductive cycles in marine invertebrates and observations on the correlations between reproductive events and environmental conditions, the mechanisms by which the reproductive cycles of individual species are controlled are very poorly understood. It has generally been accepted since the publication of the important paper of Orton (1920) that the temperature cycle in temperate and boreal regions plays an important role in determining the reproductive cycle, but the nature of the control mechanism is not, in general, understood and is likely to vary markedly between species. Environ-mental conditions such as relative daylength or biological factors such as the quantity and identity of the phytoplankton organisms (Himmelman, 1978, 1979) could also play important roles in regulating the sequence of cellular events which culminates in successful reproduction. These general problems have been discussed by Giese (1959) and more recently by Barnes (1975), Giese & Pearse (1975) and specifically in relation to Polychaeta by Clark (1979) and Olive (1980).

RAPESEED MEAL AS A PARTIAL REPLACEMENT FOR SOYBEAN MEAL IN THE DIETS OF GROWING GILTS AND OF SOWS FOR UP TO THREE REPRODUCTIVE CYCLES

1973 ◽  
Vol 53 (2) ◽  
pp. 355-363 ◽  
Author(s):  
J. P. BOWLAND ◽  
R. T. HARDIN
Keyword(s):  
Reproductive Cycle ◽  
Soybean Meal ◽  
Dietary Treatment ◽  
Rapeseed Meal ◽  
Metabolizable Energy ◽  
Partial Replacement ◽  
Gestation Length ◽  
Feed Conversion ◽  
Reproductive Cycles ◽  
Growth And Reproduction

An experiment with 32 crossbred gilts averaging 10 kg at allotment was designed to evaluate prepress-solvent extracted rapeseed meal (RSM) of Brassica campestris origin as a partial replacement for soybean meal (SBM) in diets of sows during growth or growth and reproduction when the sows were retained for three reproductive cycles. Four treatments were involved: (1) sows fed SBM throughout; (2) gilts fed 6% RSM to 90 kg and SBM for the remainder of the experiment; (3) gilts fed 6% RSM to immediately prior to first mating and SBM for the remainder of the experiment; (4) sows fed 6% RSM throughout. A second experiment with 16 mature Yorkshire sows evaluated the same RSM for one reproductive cycle only as a partial replacement for SBM when introduced into the diet immediately prior to breeding. During the growing period to 90 kg, daily feed intake, gain, and feed conversion did not differ significantly for gilts fed 0 or 6% dietary rapeseed meal, daily gain averaging 0.68 kg. Digestible energy, metabolizable energy, digestible nitrogen, and nitrogen retention coefficients were not influenced by level of dietary RSM or by period (15 or 45 kg) at which digestibility studies were conducted. Gestation length, litter size, and weight at birth and weaning were not influenced by dietary treatment in either experiment. Thyroid weights and ratio of thyroid weight to body weight of representative 2-wk-old female pigs did not differ significantly between treatments. In the first experiment, there was an average disposal of 23% of the sows per reproductive cycle because of failure to breed, failure to conceive, and other causes but these removals did not appear to be associated with treatment. The overall results suggest that up to 6% RSM of the type fed is not detrimental to sow performance when the RSM is fed during growth, throughout growth and reproduction, or when introduced suddenly at the time of breeding.

Reproductive cycle and sperm storage of female coral snakes, Micrurus corallinus and Micrurus frontalis

2020 ◽  
Vol 41 (1) ◽  
pp. 13-27 ◽  
Author(s):  
Erick Augusto Bassi ◽  
Rafaela Zani Coeti ◽  
Selma Maria de Almeida-Santos
Keyword(s):  
Reproductive Cycle ◽  
Sperm Storage ◽  
Reproductive Period ◽  
Long Term Storage ◽  
Ovulatory Period ◽  
Reproductive Cycles ◽  
Reproductive Events ◽  
Autumn And Winter ◽  
First Time

Abstract We analyzed the hypothesis that the lack of synchronization between the mating and ovulation period of Micrurus frontalis (BRT clade) is indicative of the capacity of females to store sperm. Conversely, since these reproductive events occur in the same season for Micrurus corallinus (BRM clade), sperm storage is not expected. Thus, we analyzed the reproductive cycle of female M. corallinus and M. frontalis, and investigated the occurrence of sperm storage. Our results showed that these two species of coral snakes (clades BRM and BRT) possess different reproductive cycles. Micrurus frontalis exhibits an extensive reproductive period encompassing three seasons (summer, autumn and winter), while M. corallinus directs secondary vitellogenesis and ovulation to the hottest period of the year (spring and summer). We confirm, for the first time, the strategy of sperm storage (SSr) in females of the genus Micrurus. We observed sperm storage receptacles located in the non-glandular uterus in all seasons of the year for M. corallinus and in spring, summer and autumn in M. frontalis. Furthermore, the presence of SSr in females in the non-reproductive (post-ovulatory) period, the verification of myoid cells around the receptacles and secretion of neutral carbohydrates in the lumina of SSrs may indicates a long-term storage. The posterior infundibulum is another possible region of sperm storage by the presence of tubular ciliated gland; however, reproductive studies with other species of the genus are necessary for a better understanding of the reproductive strategies of the BRT and BRM clades.

scholarly journals DIETARY RAPESEED MEAL FOR SWINE REPRODUCTION

1968 ◽  
Vol 48 (1) ◽  
pp. 57-64 ◽  
Author(s):  
F. W. Schuld ◽  
J. P. Bowland
Keyword(s):  
Reproductive Cycle ◽  
Soybean Meal ◽  
Dietary Treatment ◽  
Rapeseed Meal ◽  
Gestation Length ◽  
Growing Period ◽  
Weight Losses ◽  
Reproductive Cycles ◽  
To Receive ◽  
Daily Gain

Twenty-four sows (six littermate groups of four sows each) from 29 to 106 kg liveweight were fed either 0 or 8% solvent-extracted rapeseed meal, substituted on an isonitrogenous basis for soybean meal and wheat. The two groups were then subdivided to receive either 0 or 8% rapeseed meal in their diets through two complete reproductive cycles.Average daily gain of gilts fed rapeseed meal was lower throughout the growing period but was significantly depressed only from 90 to 106 kg liveweight. Number of services to conception, gestation weight gains, gestation length and lactation weight losses were not significantly influenced by dietary treatment. In the first reproductive cycle, sows fed rapeseed meal during the growing period farrowed only 0.2 pigs less per litter than those fed the diet containing soybean meal, but weaned 2.5 pigs less which resulted in a reduced litter weaning weight.During the second reproductive cycle, treatment during growth had no significant influence on performance of the sows or litters. Sows fed rapeseed meal during gestation and lactation performed as well during both reproductive cycles as those fed the soybean meal diet. The results indicate that levels of 8% rapeseed meal should not be fed to growing gilts that are to be saved for reproduction.

scholarly journals Seasonal changes in testicular and epididymal histology of the tropical lizard, Tropidurus itambere (Rodrigues, 1987), during its reproductive cycle

2009 ◽  
Vol 69 (2) ◽  
pp. 429-435 ◽  
Author(s):  
A. Ferreira ◽  
DN. Silva ◽  
M. Van Sluys ◽  
H. Dolder
Keyword(s):  
Electron Microscopy ◽  
Reproductive Cycle ◽  
Seasonal Changes ◽  
Seminiferous Tubule ◽  
Annual Reproductive Cycle ◽  
The Mean ◽  
Reproductive Cycles

The reproductive cycles of lizards, including Tropidurus species, have been widely studied. However, few studies describe in detail the ultrastructure and the epithelial changes in the epididymis. Using histology and trasmission electron microscopy, we show the seasonal changes in the testis and epididymis of the lizard Tropidurus itambere, during its annual reproductive cycle. The reproductive cycle of T. itambere was analysed from June 1988 to June 1989 and from June 2001 to June 2002. While the frequency of reproductive males in the population varied throughout the year, there were reproductive males in most months except for February through April. During this nonreproductive period, there is a reduction in the mean seminiferous tubule volume and few sperm were found in both the testis and the epididymis.

Reproduction and the Female Reproductive Cycle of Nyctophilus geoffroyi and N. major (Chiroptera: Vespertilionidae) from South-western Australia

1997 ◽  
Vol 45 (5) ◽  
pp. 489 ◽  
Author(s):  
D. J. Hosken
Keyword(s):  
Histological Examination ◽  
Reproductive Cycle ◽  
Western Australia ◽  
Reproductive Cycles ◽  
Reproductive Events ◽  
Vespertilionid Bats ◽  
Female Reproductive Cycle

The reproductive cycles of female Nyctophilus geoffroyi and N. major from south-western Australia are described from capture records and histological examination of tissue from fixed specimens. The sequence of reproductive events for both species was similar to that described for other vespertilionid bats from south- western Australia. Mating commenced between March and May. Sperm were stored in the caudal isthmus of the oviduct and in endometrial glands near the utero-tubal junction. Ovulation and fertilisation occurred in late August or September and twinning was common. Parturition occurred between late October and November, with volant young first captured during December, but it appeared not all N. geoffroyi females were reproductively active every year. Lactation had generally ceased by February, which was when the last detectably juvenile bats were captured.

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
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