Reproduction in Wild Canids, Canis-Familiaris, From the Eastern Highlands of Victoria

1988 ◽  
Vol 15 (4) ◽  
pp. 385 ◽  
Author(s):  
E Jones ◽  
PL Stevens
Keyword(s):  
Breeding Season ◽  
Sexual Maturity ◽  
Canis Familiaris ◽  
Seminiferous Tubules ◽  
Seasonal Breeding ◽  
Peak Period ◽  
Wild Canids ◽  
Initial Onset ◽  
Eastern Highlands ◽  
Sexually Mature

Reproduction was studied in a group of wild canids collected over four years from the eastern highlands of Victoria. While births were recorded from March to September inclusive, 78% of them took place in the winter months of June-August, with the peak occurring in July. A single breeding season each year was indicated for most, with a mean prenatal litter size of 5.5 (range 2-9). Sexually mature males were fertile throughout the year, although they exhibited a significant increase in testes weight, epididymides weight, and number of active seminiferous tubules for the months of April-June, which corresponded to the peak period of oestrus in females. The onset of first oestrus in females was variable, occurring when they were 1-4 years old, with only 36% of those less than 2 years old sexually mature. Sexual maturity in males was also variable. For animals of 10 kg (weight at initial onset of spermatogenesis) or heavier, spermatogenesis had commenced in only 63% of those less than two years old, but increased to 97% of those more than three years old. Overall this sample of canids displayed reproductive characteristics, such as a seasonal breeding season, considered typical of dingoes. However the possibility of slight changes to the original dingo breeding patterns through hybridization with domestic dogs is discussed.

Reproduction in Sminthopsis-Macroura (Marsupialia, Dasyuridae) .2. The Male

1990 ◽  
Vol 38 (2) ◽  
pp. 207 ◽  
Author(s):  
PA Woolley
Keyword(s):  
Breeding Season ◽  
Sexual Maturity ◽  
Binding Capacity ◽  
Reproductive Activity ◽  
Reproductive Organs ◽  
Histological Changes ◽  
Accessory Glands ◽  
Sminthopsis Macroura ◽  
Sexually Mature ◽  
Androgen Levels

The breeding season of S. macroura extends from June to February, and individual males (both wild- caught and laboratory-reared) are capable of breeding over extended periods during the breeding season, and for up to three seasons, in the laboratory. Gross and histological changes in the reproductive organs and endocrine changes in relation to reproductive activity have been investigated. Males do not appear to reach sexual maturity until the season following that in which they were born, although spermatorrhoea may commence in the season of birth. Testis and epididymis weight of these males, which commence spermatorrhoea late in the season, approximates that of sexually mature males early in the season but androgen levels and the weight of the accessory glands are low in all males except during the early months of the season. The age at which spermatorrhoea commences ranges from 141 to 350 days. The minimum scrota1 width at which it commences is 7.9 mm and the minimum body weight, 14.0 g. The onset of spermatorrhoea is not a function of age or season and in S. macroura should be used with caution as an indicator of impending sexual maturity. Maximum corticosteroid- binding capacity (MCBC) generally exceeded corticosteroid concentration and no androgen-related fall in MCBC was evident.

Exteroceptive Factors, Sexual Maturation and Reproduction in the Female Rat

1979 ◽  
Vol 13 (3) ◽  
pp. 283-286 ◽  
Author(s):  
M. L. Norris ◽  
C. E. Adams
Keyword(s):  
Reproductive Performance ◽  
Sexual Maturation ◽  
Sexual Maturity ◽  
Mature Male ◽  
Female Rat ◽  
Vaginal Opening ◽  
Sexually Mature

Summary Keeping a sexually mature male with a weanling female rat advanced neither the time of vaginal opening nor that of 1st oestrus. In 2 of 3 experiments females kept singly after weaning reached sexual maturity significantly earlier than did grouped females. The reproductive performance of females mated at 1st oestrus was not significantly different from that of older primiparae. 26 rats gave birth to an average of 9·3 young at 59·5 days of age, and 22 of them reared 96% of the young to weaning.

Variation III: Social Environment and Epigenetics

Mate Choice ◽  
2017 ◽  
Author(s):  
Gil G. Rosenthal
Keyword(s):  
Mate Choice ◽  
Social Interactions ◽  
Social Environment ◽  
Sexual Maturity ◽  
Horizontal Transmission ◽  
Epigenetic Modifications ◽  
Older Individuals ◽  
Mating Preferences ◽  
Sources Of Variation ◽  
Sexually Mature

This chapter focuses on social interactions, in the broadest sense, as sources of variation in mate choice and mating preferences. These interactions can be divided into three categories corresponding to when they are specified and which individuals are involved. The first includes effects that are determined before birth and transmitted vertically from parents: epigenetic modifications to the genome and the fetal or embryonic environment. The second includes influences between birth and sexual maturity, when the phenotypes of parents and/or other sexually mature, older individuals (oblique transmission) direct the development of preferences in choosers. Experience with courters and choosers after sexual maturity, or experience with other juveniles that shapes subsequent preferences, constitutes peer (horizontal) transmission.

scholarly journals Telomere dynamics from hatching to sexual maturity and maternal effects in the ‘multivariate egg’

2020 ◽  
Vol 223 (23) ◽  
pp. jeb232496 ◽  
Author(s):  
Francois Criscuolo ◽  
Roxanna Torres ◽  
Sandrine Zahn ◽  
Tony D. Williams
Keyword(s):  
Immune Response ◽  
Maternal Effects ◽  
Sexual Maturity ◽  
Negative Relationship ◽  
Individual Quality ◽  
Testosterone Treatment ◽  
Adult Females ◽  
Sexually Mature ◽  
Lps Treatment ◽  
Telomere Dynamics

ABSTRACTAvian eggs contain a large number of molecules deposited by the mother that provide the embryo with energy but also potentially influence its development via the effects of maternally derived hormones and antibodies: the avian egg is thus ‘multivariate’. Multivariate effects on offspring phenotype were evaluated in a study on captive zebra finches, by simultaneously manipulating maternally derived antibodies (MAb) by lipopolysaccharide (LPS) treatment of mothers and injection of testosterone into the egg yolk. LPS treatment had a positive effect on body mass growth at 30 days after hatching and immune response at sexual maturity, while egg testosterone treatment positively influenced immune response at fledging and courtship behaviour in sexually mature male offspring. Maternal effects are known to modulate offspring telomere length (TL). However, the multivariate effects of egg-derived maternal components on offspring telomere dynamics from hatching to sexual maturity are undefined. Here, we tested: (1) the effects of LPS and testosterone treatments on TL from hatching to sexual maturity (day 82); (2) how LPS treatment modulated TL over reproduction in adult females; and (3) the relationship between maternal and offspring TL. We predicted that TL would be shorter in LPS fledglings (as a cost of faster growth) and that TL would be longer in sexually mature adults after yolk testosterone treatment (as a proxy of individual quality). In adult females, there was an overall negative relationship between laying and rearing investments and TL, this relationship was weaker in LPS-treated females. In chicks, there was an overall negative effect of LPS treatment on TL measured at fledging and sexual maturity (day 25–82). In addition, at fledging, there was a Sex×LPS×Testosterone interaction, suggesting the existence of antagonistic effects of our treatments. Our data partially support the hypothesis that telomeres are proxies of individual quality and that individual differences in TL are established very early in life.

Reproduction in Dasykaluta-Rosamondae (Marsupialia, Dasyuridae) - Field and Laboratory Observations

1991 ◽  
Vol 39 (5) ◽  
pp. 549 ◽  
Author(s):  
PA Woolley
Keyword(s):  
Breeding Season ◽  
Granulosa Cells ◽  
Sexual Maturity ◽  
Reproductive Development ◽  
Interstitial Cells ◽  
Field Population ◽  
Interstitial Tissue ◽  
Mating Period ◽  
Reproductive Senescence ◽  
Age Class

Observations on reproduction in both wild-caught and laboratory-maintained Dasykaluta rosamondae have led to the conclusion that this species is one of 10 dasyurid marsupials in which males die soon after their first mating period. D. rosamondae have a short annual breeding season. The females are monoestrous, mating in September and bearing the young in November. Laboratory-reared young are weaned at an age of about 3 1/2-4 months, in February and March, and juveniles appear in the field population at this time. Both mates and females reach sexual maturity at an age of about 10 months. In the laboratory, males breed in only one season, after which those that survive become reproductively senile. Mature males disappear from the field population about the time the young are born; those collected shortly before this show signs of reproductive senescence. Males collected in the months after the young are weaned represent a single age-class; their reproductive development parallels that of maturing known-age males. Females are capable of breeding in at least two seasons and litters of up to eight are reared. Development of the pouch young is described. Unusual interstitial tissue masses develop in the ovaries of D. rosamondae; the granulosa cells of some follicles undergo transformation to interstitial cells, and the oocytes in these follicles degenerate, shortly before the females enter oestrus.

Reproduction in the Ningbing Antechinus (Marsupialia, Dasyuridae) - Field and Laboratory Observations

1988 ◽  
Vol 15 (2) ◽  
pp. 149 ◽  
Author(s):  
PA Woolley
Keyword(s):  
Breeding Season ◽  
Western Australia ◽  
Sexual Maturity ◽  
Males And Females

The ningbing antechinus is a species of small dasyurid marsupial found in the Kimberley region of Western Australia. Observations on reproduction have been made on newly captured and laboratory maintained specimens. The breeding season is short and mating occurs in June. The young are born after a long gestation, estimated to be between 45 and 52 days, in late July and early August. They are weaned in November when about 16 weeks old and they reach sexual maturity at 10-11 months, in the first breeding season after birth. Both males and females are potentially capable of breeding in a second season.

The Ecology of Rattus lutreolus III*. The Rise and Fall of a Commensal Population

1980 ◽  
Vol 7 (2) ◽  
pp. 199 ◽  
Author(s):  
RW Braithwaite
Keyword(s):  
Body Size ◽  
Habitat Use ◽  
Breeding Season ◽  
Sexual Maturity ◽  
Free Living ◽  
Mark Recapture

A free-living population of R. lutreolus living in and around the zoo enclosures of the Sir Colin MacKenzie Fauna Park at Healesville was studied for 27 months by use of mark-recapture trapping techniques. The demography of this population is compared with that of a natural heathland population. The breeding season was 2-3 months longer, growth of juveniles was more rapid, sexual maturity earlier, minimum survival shorter, body size larger, and habitat use less restricted in the commensal population. The evolution of the population and its decline are discussed.

Integrated analysis of sexual maturation through successive growth instars in the spider crab Leurocyclus tuberculosus (Decapoda: Majoidea)

2017 ◽  
Vol 95 (7) ◽  
pp. 473-483 ◽  
Author(s):  
Ximena González-Pisani ◽  
Pedro J. Barón ◽  
Laura S. López Greco
Keyword(s):  
Sexual Maturation ◽  
Sexual Maturity ◽  
Carapace Width ◽  
Integrated Analysis ◽  
Growth Stages ◽  
Spider Crab ◽  
Size At Maturity ◽  
Frequency Distributions ◽  
The Right ◽  
Sexually Mature

An integrative analysis of sexual maturity associated with growth was developed for the spider crab Leurocyclus tuberculosus (H. Milne Edwards and Lucas, 1842). Sexual maturity was characterized based on gonadal, morphological, morphometric, and functional sexual maturity. Progress in sexual maturation was described through 13 growth stages (instars) detected by the examination of size (carapace width) frequency distributions. Mature females displayed mature ovaries, developed vaginae, open gonopores, allometric changes in the abdomen, and ovigerous stage in the transition from instar IX to instar X. Sexually mature males presented spermatophores in the distal vasa deferentia and allometric changes in several measurements of the right chela in the transition from instar X to instar XI. However, two prepubertal phases were recognized in both sexes separated from each other by a prepubertal critical molt. Preceding the second critical molt, gonopores were sealed and vasa deferentia showed no spermatophores, and therefore neither sex was able to mate. The integrated analysis of size at maturity and size frequency distributions showed that in both sexes molt to gonadal, morphological, morphometric, and functional sexual maturity occurred in advance of the terminal molt, in contrast with patterns observed in other Majoidea.

Postnatal development of the testes in the cuis, Galea musteloides

1977 ◽  
Vol 11 (2) ◽  
pp. 87-91 ◽  
Author(s):  
W. V. Holt
Keyword(s):  
Seminiferous Tubules ◽  
Testicular Development ◽  
Testosterone Secretion ◽  
Sperm Density ◽  
Large Numbers ◽  
Testicular Weight ◽  
Testicular Size ◽  
Linear Manner ◽  
Sexually Mature ◽  
Tubule Diameter

Testicular development to 9 months of age has been studied. Seminiferous tubule diameter increased in a linear manner between 13 and 65 days of age, and there was a steep increase in testicular weight with age. At about 9 months the animals weighed 400-500 g and total testicular weight was about 10 g. This relatively large testicular size was correlated with high sperm density in the semen. Spermatogenesis commenced at about 21-25 days of age, when the first spermatids were found. Spermatozoa appeared in a small proportion of seminiferous tubules by 31-35 days of age, and were seen in the epididymides of an animal of 31 and another of 34 days. Epididymal spermatozoa were consistently present in large numbers after 60 days and this correlated with the increased frequency of mature seminiferous tubules. Leydig cell size increased rapidly from 13 to about 60 days, then remained constant. Inferences have been drawn from this and the study of spermatogenesis about the level of testosterone secretion. The results indicate that the male cuis is almost fully grown and sexually mature by about 90 days of age.

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