Seasonality of reproduction in male rock elephant shrews, <i>Elephantulus myurus</i>

Woodall, P. F.; Skinner, J. D.

doi:10.1111/j.1469-7998.1989.tb02482.x

Cited by 44 publications

(44 citation statements)

References 23 publications

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“…Contrary to the findings in Medger et al (2012b), Woodall and Skinner (1989) did not find seasonal differences in testes size, but they observed larger seminiferous tubules and increased spermatogenesis during the breeding season of E. myurus. These different results may indicate that male E. myurus retain some capacity to reproduce during some years or in some populations, whereas males may cease breeding entirely in more environmentally harsh conditions.…”

Section: Testicularcontrasting

confidence: 52%

“…Testicular length and width (mm) were measured with a pair of digital callipers (Sylvac Opto RS 232, Ultra Praezision Messzeuge GmbH, Germany) to the nearest 0.01 mm. Testicular volume (mm³) was then calculated by using the formula for the volume of an ellipsoid: V = 4/3 ab 2 , where a represents half the maximum length and b half the maximum width, as described by Woodall and Skinner (1989). The average mass (mg) and volume were calculated for both testes per male.…”

Section: Histologymentioning

confidence: 99%

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Is reproduction of male eastern rock sengis (Elephantulus myurus) from southern Africa affected by photoperiod?

2016

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Many mammals use the change in day-length to time physiological and behavioural activities on a seasonal basis. Particularly mammals from temperate regions use photoperiod to regulate reproductive functions; however, information on the role of photoperiod in small mammals from the tropics and sub-tropics is scarce. We studied the response of the reproductive system of male eastern rock sengis (Elephantulus myurus) from southern Africa to photoperiods of differing length. Elephantulus myurus breeds seasonally during the spring and summer months of the southern hemisphere despite its subtropical distribution. It is one of only three sengi species known to breed seasonally. Fourteen male E. myurus were subjected to either long-day (LD; 16L:8D) or short-day (SD; 8L:16D) photoperiods and the photoperiodic effects on the testes, testosterone concentration and body mass were examined. Testicular volume and mass, seminiferous tubule diameter as well as body mass were not significantly different between LD and SD conditions. However, plasma testosterone concentration was significantly lower in males on LD compared to SD photoperiods. Male E. myurus may not use photoperiod as a cue to control seasonal reproductive changes. Other environmental factors such as temperature, rainfall, food abundance or social factors are possibly influencing seasonal reproduction in this species.

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Section: Testicularcontrasting

confidence: 52%

Section: Histologymentioning

confidence: 99%

Is reproduction of male eastern rock sengis (Elephantulus myurus) from southern Africa affected by photoperiod?

2016

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“…Using a vernier calliper, the maximum length and width of each testis and ovary were measured. Ovarian volume as well as testicular volume was calculated using the formula for the volume of an ellipsoid, as described by Woodall and Skinner (1989): V = 4/3πab 2 , where a = ½ maximum length and b = ½ maximum breadth.…”

Section: Determination Of Reproductive Statusmentioning

confidence: 99%

Seasonal reproduction in the highveld mole-rat, Cryptomys hottentotus pretoriae (Rodentia: Bathyergidae)

Rensburg¹,

Bennett²,

Merwe³

et al. 2002

Can. J. Zool.

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The highveld mole-rat, Cryptomys hottentotus pretoriae, is a cooperatively breeding rodent that exhibits seasonal breeding and a reproductive division of labour. Body mass, reproductive-tract morphometrics, ovarian histology, and plasma oestrogen and progesterone concentrations were studied for both reproductive and non-reproductive females from 55 colonies, the main objective being to determine the inclination of this species towards seasonal breeding. Offspring are born from July through to November. However, qualitative analysis of ovarian histology revealed that reproductive females retain the potential for ovulation and subsequent production of corpora lutea during the late-summer nonbreeding period (December-March). Seasonal differences were found in ovarian morphometrics and hormone concentrations that are associated with enhanced follicular activation in April and May and subsequent conceptions from July through to November during the breeding period. The nonbreeding period coincides with maximal dispersal opportunities in the summer-rainfall areas inhabited by the highveld mole-rat. Body mass, reproductive-tract morphometrics, testicular histology, and plasma testosterone concentrations were determined for reproductive and non-reproductive males from 37 colonies. Available evidence suggests that there is a gradual increase in testicular mass for reproductive males as the breeding season approaches, but after September the testicular parameters fall. Seminiferous-tubule diameter was significantly greater in reproductive males but exhibited no seasonal variation. Testosterone concentrations were higher in reproductive males. Current data support a lack of gonadal regression in males during the nonbreeding season.Résumé : Le rat-taupe Cryptomys hottentotus pretoriae est un rongeur qui se reproduit de façon coopérative, dont la reproduction est saisonnière et qui pratique la répartition des tâches reliées à la reproduction. Nous avons déterminé la masse du corps, la morphométrie du système reproducteur, l'histologie des ovaires et les concentrations plasmatiques d'oestrogène et de progestérone chez des femelles reproductrices et non reproductrices de 55 colonies, dans le but de vérifier la tendance à une reproduction saisonnière chez cette espèce. Les petits naissent entre le début de juillet et la fin de novembre. Cependant, une analyse qualitative de l'histologie des ovaires démontre que les femelles reproductrices gardent leur potentiel d'ovulation et restent capables de produire ensuite des corps jaunes pendant la saison non reproductive en fin d'été (décembre à mars). Il existe des différences saisonnières dans les mesures morphométriques de l'ovaire et les concentrations hormonales, différences associées à la plus grande activité folliculaire en avril et en mai et aux conceptions subséquentes de juillet à la fin de novembre au cours de la période reproductive. La période non reproductive coïncide avec les probabilités maximales de dispersion dans les régions à pluies estivales habitées par le rat-taupe...

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“…The measurements for the paired gonads were averaged. From these data the average gonadal volume was determined using the equation for the volume of an ellipsoid V = 4/3 πab 2 , where a is one half maximum length and b is one half maximum width (Woodall and Skinner, 1989).…”

Section: Histologymentioning

confidence: 99%

Reproductive patterns in the Baluchistan gerbil, Gerbillus nanus (Rodentia: Muridae), from western Saudi Arabia: The role of rainfall and temperature

Sarli

Lutermann

Alagaili

et al. 2015

Journal of Arid Environments

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There is little information pertaining to the reproductive biology of the Baluchistan gerbil (Gerbillus nanus) despite a broad distribution throughout the Middle East. In the current study, body mass, reproductive-tract morphometrics plus gonadal histology and endocrine profiles of males and females were studied over 12 consecutive months in a field population of Baluchistan gerbils from the western region of Saudi Arabia in an attempt to gain insights into a) the environmental zeitgeber(s)that correlate with reproduction as well as b) to assess if reproduction is seasonal or aseasonal in this species. With the exception of testosterone all male reproductive indicators varied seasonally and were lower during winter than the rest of the year and most increased with rainfall. In contrast, ovarian mass and volume as well as immature follicle counts showed no seasonal patterns and were independent of rainfall or temperature. First pregnancies were obsereved in late spring coinciding with the increased progesterone concentrations and peaked in summer. This was accompanied by seasonal peaks in the number of Graafian follicles and corpora lutea in females and these parameters were significantly correlated with temperature, but not rainfall In the Arabian Peninsula male, but not female Baluchistan gerbils show seasonal recrudescence and this appears to be correlated largely to rainfall.

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Seasonality of reproduction in male rock elephant shrews, Elephantulus myurus

Cited by 44 publications

References 23 publications

Is reproduction of male eastern rock sengis (Elephantulus myurus) from southern Africa affected by photoperiod?

Is reproduction of male eastern rock sengis (Elephantulus myurus) from southern Africa affected by photoperiod?

Seasonal reproduction in the highveld mole-rat, Cryptomys hottentotus pretoriae (Rodentia: Bathyergidae)

Reproductive patterns in the Baluchistan gerbil, Gerbillus nanus (Rodentia: Muridae), from western Saudi Arabia: The role of rainfall and temperature

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