Seasonal adiposity and androstenedione production as a possible mechanism for asynchronous reproductive activity between males and females of vespertilionid bat, Scotophilus heathi

2000 ◽  
Vol 51 (1) ◽  
pp. 37-44
Author(s):  
A. Krishna ◽  
Abhilasha ◽  
K. Singh
Keyword(s):  
Reproductive Activity ◽  
Males And Females

Reproductive biology of the false coral snake Oxyrhopus guibei (Colubridae) from southeastern Brazil

2002 ◽  
Vol 23 (4) ◽  
pp. 495-504 ◽  
Author(s):  
Otavio Marques ◽  
Lígia Pizzatto
Keyword(s):  
Body Size ◽  
Reproductive Biology ◽  
Rainy Season ◽  
Reproductive Activity ◽  
Climatic Conditions ◽  
Southeastern Brazil ◽  
Coral Snake ◽  
Males And Females ◽  
Reproductive Cycles ◽  
Number Of Individuals

AbstractThe reproductive biology of the false coral snake, Oxyrhopus guibei, was studied through dissection of 496 specimens, combined with observations on captive individuals. Males mature with smaller body size than females, females attain much larger body size, and male-male combat is not expected. Clutch size ranged from 3 to 20, and was correlated with female length. Reproductive cycles in both males and females seem to be continuous, with vitellogenesis and spermatogenesis occurring throughout the year. Reproductive activity in both sexes decreased at the end of the rainy season possibly due to previous intense reproductive activity in more favorable climatic conditions. The smaller number of individuals collected at the end of the rainy season apparently occurs due to the decrease of reproductive activity of this snake.

The reproductive cycle of the newt Triturus italicus

1992 ◽  
Vol 13 (2) ◽  
pp. 121-133 ◽  
Author(s):  
Fabio M. Guarino ◽  
Vincenzo Caputo ◽  
Francesco Angelini
Keyword(s):  
Body Weight ◽  
Reproductive Cycle ◽  
Annual Variation ◽  
Southern Italy ◽  
Fat Body ◽  
Reproductive Activity ◽  
Male And Female ◽  
Egg Deposition ◽  
Males And Females ◽  
Mountain Population

AbstractThis paper describes the reproductive cycle in male and female newts Triturus italicus (Peracca, 1898) from a mountain population living in southern Italy. The male shows a well-defined seasonal testicular cycle: spermatogenesis almost stops from November to March, resuming in April-May; the maturative stage of spermatogenesis occurs in summer and spermiohistogenesis is completed by late October. Spermiation starts in late autumn and culminates in the next spring. The female shows a seasonal ovarian cycle. Vitellogenesis starts in September; ovulation and egg deposition occur between late January and early June. Thus potentially long reproductive activity is demonstrated in both males and females of T italicus. Testicular and ovarian weights seem to be reliable indices of the reproductive status of an animal. Annual variation in gonadal weight appears unrelated to annual variation in fat body weight in both sexes.

Ecological strategies of a small hibernator, the western jumping mouse Zapus princeps

1983 ◽  
Vol 61 (1) ◽  
pp. 232-240 ◽  
Author(s):  
Jack A. Cranford
Keyword(s):  
Laboratory Experiments ◽  
Habitat Preferences ◽  
Reproductive Activity ◽  
Home Range Size ◽  
Fat Deposition ◽  
Site Quality ◽  
Ecological Strategies ◽  
Density Maximum ◽  
Males And Females ◽  
Coherent Picture

The seasonal emergence, reproduction, diet, fat deposition, and immergence of six wild populations of Zapus princeps from elevations of 1860–2900 m were studied by trap–recapture methods and laboratory observations from April 1974 to November 1978. Emergence timing varied widely between and within sites in different years. It was not related to increasing elevation but to site quality. Vegetative growth was an excellent predictor of emergence timing at all sites. Emergence of males and females was synchronous except above 2200 m where males preceded females by 3–9 days. Field and laboratory experiments and observations were made on Z. princeps, including habitat preferences, competitive relationships, population density (maximum = 32.4/ha), length and timing of the active cycle (87 days), reproductive activity (1 litter/year), litter size [Formula: see text], age structure of populations, growth rates, seasonal fat deposition (0.65 g/day),and home-range size(0.17–0.61 ha). This attempts to formulate a coherent picture of the system of strategies by which a small hibernator adapts to its environment.

Short term changes in sex ratio and density alter coercive male mating tactics

Behaviour ◽  
2010 ◽  
Vol 147 (11) ◽  
pp. 1431-1442 ◽  
Author(s):  
James Cureton II ◽  
Raelynn Deaton ◽  
Rachel Martin
Keyword(s):  
Sex Ratio ◽  
Reproductive Activity ◽  
Operational Sex Ratio ◽  
Mating Frequency ◽  
Male Mating ◽  
Mating Tactics ◽  
Short Term ◽  
Classic Theory ◽  
Males And Females ◽  
The Impact

AbstractShort term fluctuations in operational sex ratio (OSR) and density can strongly influence male mating, often exacerbating conflict between males and females. Livebearing fishes of the genus Gambusia are ideal for investigating sexual conflict because males of all sizes mate coercively. In this study, we tested how short-term fluctuations in OSR and density influence coercive male mating behaviours. Specifically, we tested the prediction that as OSR becomes more female biased, males will mate with all available females. In contrast, as OSR becomes more male biased, male aggression will inhibit mating frequency. As predicted, males mated with more females as the number of available females increased. Moreover, males were less aggressive as the proportion of females increased and more aggressive as the number of males increased. This resulted in an inverse relationship between mating and aggression with OSR and density. Coercive males attempt to maximize their reproductive success by mating with all available females, which supports classic theory on the impact of OSR and density on reproductive activity.

scholarly journals Reproductive aspects of Dendropsophus sanborni (Anura, Hylidae) in northeastern Argentina

2014 ◽  
Vol 104 (4) ◽  
pp. 432-438 ◽  
Author(s):  
Lucila M. Curi ◽  
Gabriela. B. Olea ◽  
Blanca B. Álvarez ◽  
Jorge A. Céspedez ◽  
Daniel M. Lombardo
Keyword(s):  
Sexual Dimorphism ◽  
Body Mass ◽  
Reproductive Activity ◽  
Testicular Volume ◽  
Reproductive Pattern ◽  
Males And Females ◽  
Reproductive Cycles ◽  
Northeastern Argentina

Reproductive aspects of Dendropsophus sanborni (Anura, Hylidae) in northeastern Argentina. The aim of this investigation was to characterize reproductive aspects of Dendropsophus sanborni (Schmidt, 1944) (Anura, Hylidae) in the northwest of Corrientes province, in northeastern Argentina. The reproductive cycles of males and females, the existence of sexual dimorphism and the male’s vocalization period were analyzed. Samplings were made from September 2011 to August 2012. Dendropsophus sanborni showed a prolonged reproductive pattern because reproductive activity was observed during most part of the year. Calling males were recorded all months except in July. The spermatogenic cycle can be characterized as potentially continuous. In males, snout-vent length was significantly correlated with mean testicular volume. The species showed sexual dimorphism in body mass, with females larger than males. Post-ovulatory females were found from March to June and most females had oocytes at different stages of maturity, with abundant post-vitellogenic oocytes from August to December.

scholarly journals Observation of Hermann’s Tortoise (Testudo hermanni) C Lutching without the Presence of Males and Eggshell Mortality on a Large Tortoise Farm in Slovenia Over a Three-Year Period

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Stvarnik Mateja ◽  
Lindtner-Knific Renata ◽  
Štokar Žan ◽  
Gregurić Gračner Gordana ◽  
Mićunović Jasna ◽  
...  
Keyword(s):  
Embryonic Development ◽  
Reproductive Activity ◽  
First Year ◽  
Egg Weight ◽  
The Third ◽  
Before And After ◽  
Testudo Hermanni ◽  
Males And Females ◽  
Second Year ◽  
Second Clutch

AbstractThe aim of this study was to determine the percentage of hatched and fertilized eggs in female Hermann’s tortoises before and after the removal of males after breeding.A breeding group of Testudo hermanni boettgeri with 50 females and 12 males was included in the study. In the first year, all adults were together in the same habitat until reproductive activity was observed. After the end of May, the males and females were separated for the next two active seasons. The number of eggs and number of second clutches decreased gradually. In the first year, 76.0% of females laid eggs; in the second year, 24.0%; and in the third year, only 8.0%. Second clutches were observed in ten females (26.3%) in the first year, while in the next two years, one female had a second clutch. There was a small but significant correlation between the weight of a single tortoise and the number of eggs laid but no significant correlation between the weight of the tortoise and its average egg weight. The weight (15.1-16.8 g), length (33.9-36.1 mm) and width of each egg (27.5-28.0 mm) was measured.During the laying season, the eggs were put into incubators. The incubation length varied from 52 to 70 days. After the end of incubation, eggshell mortality and its causes (19.3-52.5%) were examined. In the first year, the viability rate of the incubated eggs was 80.7%; in the second year, 80.5%; and in the third year, 47.8%. Among the unhatched eggs in the first year, 62.5% were unfertilized, 53.1% were infected, 28.1% were dehydrated and 21.9% were found in various stages of embryonic development.

Effect of Season and Sex on the Photopic Spectral Sensitivity of the Three-Spined Stickleback

1968 ◽  
Vol 49 (3) ◽  
pp. 679-687
Author(s):  
JOHN CRONLY-DILLON ◽  
SANSAR C. SHARMA
Keyword(s):  
Spectral Sensitivity ◽  
Gasterosteus Aculeatus ◽  
Threshold Value ◽  
Reproductive Activity ◽  
Consistent Difference ◽  
Optomotor Response ◽  
Males And Females

1. The photopic spectral sensitivity of the three-spined stickleback Gasterosteus aculeatus was obtained behaviourally using the optomotor response as the index of sensitivity. Our experiments were designed to determine whether spectral sensitivity was affected (i) by the sex of the fish, and (ii) by season. 2. In females γmax occurred at approximately 510 run. and 594 nm. In males the corresponding values were 502 nm. and 594 nm. Thus there appears to be a small but consistent difference of the order of 10 nm. between the shorter wavelength peaks of males and females. 3. In males the spectral sensitivity appears to remain virtually unchanged throughout the year. By contrast, during the summer months when reproductive activity is highest, the optomotor threshold for females at the red (594 nm.) end of the spectrum is considerably lower than the corresponding threshold value for males. This difference between the sexes disappears during winter months when reproductive activity is at a minimum.

Reproductive Behaviour of the Cod (Gad Us Callarias L.)

Behaviour ◽  
1961 ◽  
Vol 18 (3) ◽  
pp. 177-197 ◽  
Author(s):  
Vivien M. Brawn
Keyword(s):  
Aggressive Behaviour ◽  
Reproductive Activity ◽  
Reproductive Behaviour ◽  
Lateral View ◽  
Dominant Male ◽  
Vertical Movements ◽  
Spawning Period ◽  
Spawning Behaviour ◽  
Males And Females ◽  
Median Fins

AbstractThree weeks before spawning, aggressive and reproductive behaviour was seen in a group of thirteen captive cod. By aggression directed against males and females the most vigorous males were able to establish territories in the pre-spawning period. Less vigorous males and unripe females formed an inactive group outside the territory. All spawning observed occurred in the territory of the dominant male. The amount of reproductive activity was closely linked with dominance in the males. Behaviour culminating in spawning was initiated by a female entering the territory of the male. Males were able to distinguish the sex of mature intruding fish during the spawning period. The distinction appeared to be based on the slow swimming, unafraid approach of the female compared with the quick movements and readiness to flee shown by the males. The male approached ripe females and presented a lateral view of the flaunting display. In this display the median fins are fully erected and the male moves in front of the female with many unnecessary turns sometimes accompanied by a low grunting sound. Ripe females followed flaunting males for ten to fifteen minutes. Then if the female became stationary at the bottom of the tank it was prodded ventrally by the male, which caused it to swim upwards. At the surface the male mounted the female dorsally and then immediately slipped down one side into a ventral mount with the male inverted below the female. In this position the cod spawned while swimming in circles at the surface. No interest was shown by the rest of the group in the spawning. After spawning the spent female returned to the bottom of the tank and rejoined the group of inactive cod. The pattern of spawning behaviour was often initiated but failed to reach completion because of the inappropriate response of the female at some stage. During successive entries the courtship behaviour was carried to later stages until the female swam to the surface and spawned. Aggressive behaviour during the spawning period seems to be important in allowing only the most vigorous males to spawn and preventing interference by other males in the courtship pattern. The production of sounds by the males was used to enforce aggressive behaviour and stimulated the female. It is suggested that, as much of the behaviour leading to spawning involves vertical movements, natural cod shoals may be stratified with a layer of vigorous males above a group of females and less vigorous males.

Seasonal patterns in the reproductive activity of barnacle-dwelling littorinids

2000 ◽  
Vol 80 (5) ◽  
pp. 821-826 ◽  
Author(s):  
Lisa J. Johnson ◽  
Peter J. Mill ◽  
Susan L. Hull ◽  
Paul Ducrotoy ◽  
Kevin J. Caley
Keyword(s):  
East Coast ◽  
Reproductive Activity ◽  
Early Summer ◽  
Seasonal Patterns ◽  
Seasonal Component ◽  
North East ◽  
The North ◽  
Littorina Arcana ◽  
Males And Females

The reproductive activity of a population of barnacle-dwelling littorinids at Peak Steel, on the north-east coast of England, was investigated. Variation in the number of mature males and females, expressed as a percentage of the whole population, showed a marked difference among the barnacle-dwelling littorinids. Littorina neglecta displayed a distinct seasonal component to its reproductive activity, with a peak in early summer. Littorina arcana B also displayed a distinct seasonal component, with a lull in the summer months. However, L. saxatilis B maintained its reproductive activity all year, but with an increase in output in the summer. The reproductive activity of both L. arcana B and L. saxatilis B follow similar patterns of reproductive activity as their typical non barnacle-dwelling forms, suggesting that these are true barnacle-dwelling ecotypes. The controversy surrounding the specific status of L. neglecta is also discussed.

scholarly journals Size, sex and maturity of the squid Lolliguncula diomedeae (Cephalopoda: Loliginidae) in the Gulf of Tehuantepec, México.

2015 ◽  
Vol 7 (1) ◽  
pp. 79-87
Author(s):  
María del Carmen Alejo-Plata ◽  
José Luis Gómez-Márquez ◽  
Jorge Eduardo Herrera-Galindo
Keyword(s):  
Sexual Maturity ◽  
Gonadosomatic Index ◽  
Reproductive Activity ◽  
Allometric Growth ◽  
Relationship Type ◽  
Length Relationship ◽  
Gulf Of Tehuantepec ◽  
Males And Females ◽  
First Maturity ◽  
Size At First Maturity

There is practically no information on the biology of Lolliguncula (Loliolopsis) diomedeae. We analyzed specimens caught in four shrimp fishing trips in the Gulf of Tehuantepec in 1999-2001, 2004 and 2006.Sexual maturity and gonadosomatic index (GSI) were used as indicators of reproductive activity. A total of 1 200 individuals were captured, 89% female. Females ranged from 35 to 97mm in mantle length (LDM),with a mode at 80mm and weights 2 to 30,9g; males 20,7 to 65mm LDM with a mode at 35-40mm and weights from 0,4 to 12g. Differences in the LDM and the PT between males and females were significant (KS, p<0,05). The sex ratio was 8:1 H:M (p <0,05). The weight-length relationship type is potential for both sexes, with a negative allometric growth.83% of mature females had high IGS values, in contrast to less than 20% of mature males. The size at first maturity (L50) indicates that males (42,7mm LDM) mature when shorter than females (74,5mm LDM). Maturity, IGS and oceanographic features of the Gulf of Tehuantepec indicate that L. diomedeae spawn there.

Sign in / Sign up

Export Citation Format

Share Document