Seasonal effects of photoperiod and temperature on spermatogenesis and male secondary sexual characters in the three-spined stickleback, Gasterosteus aculeatus L.

1982 ◽  
Vol 60 (12) ◽  
pp. 3377-3386 ◽  
Author(s):  
Bertil Borg
Keyword(s):  
High Temperature ◽  
Breeding Season ◽  
Annual Cycle ◽  
Gasterosteus Aculeatus ◽  
Seasonal Effects ◽  
Secondary Sexual Characters ◽  
Kidney Hypertrophy ◽  
Summer Decline ◽  
Secondary Sexual

Effects of photoperiod (16 h light (L): 8 h dark (D) and 8 h L: 16 h D) and temperature (18 and 8 °C) on spermatogenesis and androgen-dependent kidney hypertrophy in the three-spined stickleback were studied in alternate months of the year. In winter 16 h L: 8 h D in combination with 18 °C stimulated secondary sexual characters, whereas in spring other regimes were also stimulatory. Spermatogenesis was more active and the kidney more suppressed in 8 h L: 16 h D at 18 °C than in other groups in winter. In the natural annual cycle spermatogenesis is quiescent from the beginning of winter until the end of the breeding season in summer. Decline of secondary sexual characters in July is accelerated by high temperature. High kidney epithelium is never found together with vigorous spermatogenesis, indicating androgen-inhibition as a major factor in the control of spermatogenetic activity.

scholarly journals V. The reproductive cycle of the three-spined stickleback, Gasterosteus aculeatus , Linn

1931 ◽  
Vol 219 (462-467) ◽  
pp. 197-279 ◽  
Keyword(s):  
Reproductive Cycle ◽  
Gasterosteus Aculeatus ◽  
Reproductive Organs ◽  
Temperate Climate ◽  
Experimental Examination ◽  
Secondary Sexual Characters ◽  
Secondary Sexual

A study has been made of the cyclical changes which occur annually in the reproductive organs of a fish living in a temperate climate. The fish chosen has marked seasonal secondary sexual characters in the male, and the relation between the development of these and the changes in the testis has been investigated in detail. An experimental examination, suggested by these studies, has been made of the possible influences of physical and biological changes in the environment on the reproductive cycle. The migration of the fish which occurs in connection with reproduction was examined to ascertain whether it bears a relation to the reproductive cycle.

Effectiveness of several androgens in stimulating kidney hypertrophy, a secondary sexual character, in castrated male three-spined sticklebacks, Gasterosteus aculeatus

1993 ◽  
Vol 71 (11) ◽  
pp. 2327-2329 ◽  
Author(s):  
Bertil Borg ◽  
Efthimia Antonopoulou ◽  
Eva Andersson ◽  
Tomas Carlberg ◽  
Ian Mayer
Keyword(s):  
Body Weight ◽  
Gasterosteus Aculeatus ◽  
Secondary Sexual Character ◽  
Kidney Tubules ◽  
Sexual Character ◽  
Kidney Hypertrophy ◽  
Stimulation Of ◽  
Secondary Sexual

The effectiveness of different androgens in stimulating hypertrophy of the kidney tubules, a male secondary sexual character, was studied by injecting castrated male sticklebacks with androgens at doses of 0.008–25 μg∙g body weight−1∙day−1 (or control injections were given) for 3 weeks. The doses (μg/g) needed to give 50% stimulation of the kidney epithelium height were as follows: 11-ketotestosterone (OT), 0.047; 11β-hydroxyandrostenedione, 0.070; 11-ketoandrostenedione, 0.11; 5α-androstane-3,11,17-trione, 1.1; 5α-dihydrotestosterone, 1.8; 17β-hydroxy-5α-androstane-3,11-dione, 3.0; and testosterone, 15.2. Androstenedione and 5β-androstane-3,11,17-trione did not reach half-effectiveness at the dose tested (5 μg/g). It is suggested that OT is the physiologically relevant androgen in this case.

Relationships between body size and secondary sexual characters, and sperm characters in male Dolly Varden char (Salvelinus malma )

2016 ◽  
Vol 26 (3) ◽  
pp. 397-402 ◽  
Author(s):  
Toshiaki Yamamoto ◽  
Noritaka Hirohashi ◽  
Eiji Fujiwara ◽  
Tatsuya Suzuki ◽  
Hatsuna Maruta ◽  
...  
Keyword(s):  
Body Size ◽  
Dolly Varden ◽  
Salvelinus Malma ◽  
Dolly Varden Char ◽  
Secondary Sexual Characters ◽  
Sperm Characters ◽  
Secondary Sexual

Environmental influence on maturation and dominance relationships in the three-spined stickleback (Gasterosteus aculeatus L.): temperature competes with photoperiod for primacy

2009 ◽  
Vol 38 (4) ◽  
Author(s):  
Ewa Sokołowska ◽  
Ewa Kulczykowska
Keyword(s):  
High Temperature ◽  
Visual Information ◽  
Gasterosteus Aculeatus ◽  
Environmental Influence ◽  
Gonadal Development ◽  
Constant Darkness ◽  
Dominance Relationships ◽  
Final Maturation ◽  
Maturation Rate ◽  
Spawning Periods

Environmental influence on maturation and dominance relationships in the three-spined stickleback (In this study, the influence of a combination of different photoperiods and temperatures on the final maturation and social interactions in three-spined sticklebacks was investigated. Water temperature appears to be the principal signal affecting gonadal development and breeding activity of sticklebacks in pre-spawning and spawning periods. Males can mature independently of photoperiod and a stimulatory effect of high temperature is not diminished by light deprivation. On the other hand, low temperature can inhibit the development of secondary sexual characters in males exposed to long day or constant light. In females, lighting seems to be more decisive for complete maturation and the lack of light delays the maturation rate, even in high temperature. While kept under the same conditions, males mature quicker than females. The presence of light and visual information are crucial to establish the social position of individuals in the group. In light, a rigid social hierarchy with one dominant, sexually active male is observed. In constant darkness, however, several males in the group demonstrate every sign of sexual activity.

Differentiation of the sexual characters and onset of maturity in the males of the "red claw" crayfish, Cherax quadricarinatus (Von Martens, 1898) (Astacidea, Astacida, Parastacidae)

2010 ◽  
Vol 60 (2) ◽  
pp. 195-208 ◽  
Author(s):  
Laura Susana López Greco ◽  
Fernanda Jimena Vazquez
Keyword(s):  
Sexual Maturity ◽  
Vas Deferens ◽  
Developmental Stages ◽  
Stage I ◽  
Early Event ◽  
Cherax Quadricarinatus ◽  
Secondary Sexual Characters ◽  
Single Structure ◽  
Red Claw Crayfish ◽  
Secondary Sexual

AbstractThe differentiation of the male reproductive system, the copulatory structures, "red patch" and onset of sexual maturity were studied in Cherax quadricarinatus. For this characterization 353 males were observed, dissected and processed for histological analysis. Three developmental stages were identified. At stage I the testes are two parallel cords with a few lobes or acinii, connected medially by a short thin bridge (X-shape) and the vasa deferentia are straight transparent cords. In the second stage, more lobulated testes present an H-shape and the vas deferens begins to differentiate into three distinct regions: proximal, medial and distal. In the last stage testes are two parallel cords tending to fuse along their entire length and become a single structure. From this stage, the development of the "red patch" occurs and spermatophore formation is observed in the vas deferens giving it white colour. These primary and secondary sexual characters could indicate the onset of sexual maturity. The morphology of the copulatory structure is lobular at stage I and it differentiates into an elongated structure during stage II. This study shows that in C. quadricarinatus the differentiation of primary and secondary sexual characters of males starts simultaneously and very early in development (0.09-0.10g achieved nearly 1 month old) and that acquisition of sexual maturity is also an early event (6g achieved nearly 3 month old). The compared features within Astacidea and Decapoda and the possible applications in the analysis of phylogenetic relationships between different taxa are discussed.

scholarly journals Myxomatosis in farmland rabbit populations in England and Wales

1989 ◽  
Vol 103 (2) ◽  
pp. 333-357 ◽  
Author(s):  
J. Ross ◽  
A. M. Tittensor ◽  
A. P. Fox ◽  
M. F. Sanders
Keyword(s):  
Breeding Season ◽  
Annual Cycle ◽  
Seasonal Pattern ◽  
Mortality Factor ◽  
Mass Movements ◽  
Wild Rabbit ◽  
Regulatory Effect ◽  
Methods Of Calculation ◽  
Attenuated Virus ◽  
Virus Strains

SUMMARYThe overall pattern and consequences of myxomatosis in wild rabbit populations were studied at three farmland sites in lowland southern England and upland central Wales between 1971 and 1978. When results from all years were combined, the disease showed a clear two-peaked annual cycle, with a main autumn peak between August and January, and a subsidiary spring peak during February to April.Rabbit fleas, the main vectors of myxomatosis in Britain, were present on full-grown rabbits in sufficient numbers for transmission to occur throughout the year, but the observed seasonal pattern of the disease appeared to be influenced by seasonal mass movements of these fleas. However other factors were also important including the timing and success of the main rabbit breeding season, the proportion of rabbits which had recovered from the disease and the timing and extent of autumn rabbit mortality from other causes.Significantly more males than females, and more adults and immatures than juveniles, were observed to be infected by myxomatosis. Only 25–27% of the total populations were seen to be infected during outbreaks. Using two independent methods of calculation, it was estimated that between 47 and 69% of infected rabbits died from the disease (much lower than the expected 90–95% for fully susceptible rabbits with the partly attenuated virus strains that predominated). Thus it was estimated that 12–19% of the total rabbit populations were known to have died directly or indirectly from myxomatosis.Although the effects of myxomatosis were much less than during the 1950s and 1960s, it continued to be an important mortality factor. It may still have a regulatory effect on rabbit numbers, with autumn/winter peaks of disease reducing the numbers of rabbits present at the start of the breeding season.

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