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1.
In a longitudinal study of individually identified wild baboons in Amboseli National Park, Kenya, we collected data on physical development and reproductive maturation. Confirming and extending our earlier results, we demonstrated that the ratio of ages at which developmental milestones occur in the field as compared to those under extensive provisioning or in captivity were approximately 5:3. The age range for some developmental milestones was quite narrow and discrete, while for others there was considerable between-individual variability and more gradual changes. For infants, only the change from pink to gray of the paracallosal skin occurred within a brief age span. For older animals two important developmental events are readily identified and occur within a fairly narrow age range: Rapid enlargement of testes at 5 to 6 years for males and onset of menarche at 4 to 5 ½ years for females. In the present report, we considered some consequences of accelerated or delayed maturation. We further explored the need to employ different age-class criteria for different research problems.  相似文献   

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3.
R. Moss  A. Watson 《Ibis》1984,126(2):212-220
Samples of Ptarmigan eggs were hatched in captivity. They had been taken from ground adjacent to study areas where the wild birds' breeding success by early August, and their food plants, were measured.
Almost all deaths of chicks in captivity occurred within a few days of hatching and examination postmortem showed no specific cause. The proportion of chicks which died in captivity before 15 days of age varied markedly between years and study areas. These variations occurred in parallel with variations in breeding success in the wild populations from which the eggs had been taken. It was concluded that the survival of chicks both in captivity and in the wild was determined in part before the eggs hatched.
Variations in breeding success from year to year were correlated with the number of days that the food plants had been growing before the hens finished laying. Breeding success in the wild and chick survival in captivity were better for a 'rich' area overlying some base-rich rocks than for a 'poor' one overlying granite and with less blaeberry. It was inferred that, as in Red Grouse, maternal nutrition affected breeding success through the quality of the eggs.  相似文献   

4.
The social behaviour of individually identified squids was observed over a period of 4 mo. Squids were reared in captivity and maintained in a shoal of up to 18 animals. Distances between animals averaged 1.6 body lengths, similar to the 1.2 body lengths of wild teleost fish schools. Smaller animals schooled less frequently and were found at the periphery, and familiar and unfamiliar animals shoaled together. Eighty-six apparent reproductive events were observed. This species of squid, Sepioteuthis lessoniana, is not sexually dimorphic to the human eye and male squids copulated with both males and females but they directed their attention disproportionately towards females. Most copulations occurred more than a month before spawning, lasted only a few seconds and, unlike field observations on spawning grounds, were not followed by mate-guarding. Two body patterns are described that were used consistently in social interactions by both males and females; these patterns were both associated with reproductive behaviour but their exact function was unclear. A sister species, Sepioteuthis sepioidea, has been described as showing complex social behaviour; in S. lessoniana, no evidence for such behaviour was seen.  相似文献   

5.
Reproduction in Red pandas, Ailurus fulgens (Carnivora: Ailuropodidae)   总被引:3,自引:0,他引:3  
Several aspects were studied of the reproductive biology of the Red panda, Ailurus fulgens , in captivity at the National Zoological Park (NZP), Washington, D.C. over a six-year period. This species exhibits marked mating and birth seasons and produces litters averaging 1·7 with a sex ratio of 17·2 males to one female. Sexual maturity is reached in the second breeding season after birth or when animals are approximately 18 months of age. Growth, development and mortality of young are discussed. This study noted a wide range in observed gestation periods, averaging 131 days, which may be due to one or a combination of factors. Breeding behaviour is briefly noted and compared to that in other, related species. Predictions about reproductive and other life strategies of Red pandas in nature are drawn by fitting captive data into accepted ecological models.  相似文献   

6.
川西米亚罗林区不同海拔岷江冷杉生长对气候变化的响应   总被引:3,自引:0,他引:3  
徐宁  王晓春  张远东  刘世荣 《生态学报》2013,33(12):3742-3751
为分析青藏高原东缘半湿润区树木生长与气候关系随海拔变化的规律,于川西米亚罗林区分别在高、中、低海拔选取3个采样点,共采集132棵岷江冷杉年轮样芯,建立了最长达170a(1842-2011年)3个海拔高度的差值年表.岷江冷杉年轮指数与气候因子的相关分析表明:随海拔高度降低,温度与生长的负相关呈增加趋势.高海拔岷江冷杉径向生长与前—年冬季最低温呈显著正相关,中低海拔与当年春季均温、最高温和年均最高温呈显著负相关.低海拔岷江冷杉与当年4月降水呈显著正相关,随海拔升高降水与岷江冷杉生长的相关性降低.中低海拔岷江冷杉年表与4、5月帕尔默干旱指数(P DSI)呈显著正相关,表明在中低海拔存在春季干旱胁迫,抑制了岷江冷杉的生长.另外,大龄树木比小龄树木对气候变化的响应更敏感.  相似文献   

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8.
The effect of both male and female age was investigated on certain reproductive attributes, viz. mating incidence, mating duration, fecundity, percent egg viability, ratio of reproductive and non‐reproductive periods and reproductive rate, of an aphidophagous ladybird, Cheilomenes sexmaculata (Fabricius). Females started mating at the age of 8 hours post‐emergence (PE) and males at the age of 2 days PE. Mating in the laboratory was a male‐dominated phenomenon. The mating duration and reproductive rate of 10‐day‐old females when mated with males of varying ages increased up to the male age of 60 days, and thereafter decreased, whereas, fecundity, egg viability and ratio of reproductive and non‐reproductive periods increased up to the male age of 50 days, and thereafter declined. However, when females of varying ages were mated with 10‐day‐old males, fecundity and reproductive rate increased up to 40 days of female age, respectively, then decreased. The ratio of reproductive and non‐reproductive periods increased with increasing age of females. Mating age for optimal reproductive output was 10J50‐day‐old males and NE to 40‐day‐old females. Reproductive cessation in males was recorded after 50 days PE, whereas in females at the age of 40 days PE. Higher mating durations lead to elevated reproductive rates. Delay in the reproductive phase was positively correlated with longevity. The results of this study may aid mass multiplication of this ladybird by identifying and promoting usage of adults of optimal age. Our results also enhance our understanding of the effect of age on reproductive attributes in ladybirds.  相似文献   

9.
K Ohno  Y Niwa  S Kato  K Koyasu  S Oda  K Kondo 《Jikken dobutsu》1992,41(4):449-454
The dsinezumi shrew (Crocidura dsinezumi), a small insectivore, has been bred for the first time as a laboratory animal. The original animals were captured using Sherman's live traps and transferred into wooden cages. After several generations they were housed in plastic cages. Their diet consisted of trout pellets, cat food, and water provided ad libitum. Monogamous pairs were housed together for 2-3 weeks for mating, and the male was separated from the female during delivery and nursing. In captivity, the reproductive activity was observed throughout the year and the gestation period was estimated at 28-30 days with a litter size of between 1 and 4 pups. Pups grew very rapidly, and reached adult body size (mean: male, 9.7 g; female, 8.3 g) and sexual maturation at 6-8 weeks of age. The reproductive life was estimated at one and a half years, while the longevity was approximately 2 years.  相似文献   

10.
The black-footed ferret (Mustela nigripes), which was extirpated from its native North American prairie habitat during the 1980s, is being reintroduced to the wild because of a successful captive-breeding program. To enhance propagation, the reproductive biology of this endangered species is being studied intensively. The typical life span of the black-footed ferret is approximately 7 yr. Female fecundity declines after 3 yr of age, but the influence of age on male reproduction is unknown. In this study, testis volume, seminal traits, sperm morphology, and serum testosterone were compared in 116 males from 1 to 7 yr of age living in captivity. Results demonstrated that testes volume during the peak breeding season was similar (P > 0.05) among males 1 to 5 yr of age, reduced (P < 0.05) among males 6 yr of age, and further reduced (P < 0.05) among males 7 yr of age. Motile sperm/ejaculate was similar in males 1 to 6 yr of age but diminished (P < 0.05) in those 7 yr of age. Males at 6 and 7 yr of age produced fewer (P < 0.05) structurally normal sperm than younger counterparts; however, serum testosterone concentrations were not reduced (P > 0.05) in older males. Histological comparison of testicular/epididymal tissue from 5- and 7-yr-old black-footed ferrets confirmed that the interval between these two ages may represent a transitional period to reproductive senescence. In summary, functional reproductive capacity of male black-footed ferrets exceeds that of females by at least 2 yr. Testes and seminal quality are indistinguishable among males 1 to 5 yr of age, with progressive reproductive aging occurring thereafter.  相似文献   

11.
A study of the growth and development of the Tasmanian devil (Sarcophilus harrisii) was undertaken on a litter born at Healesville Sanctuary in Healesville, Victoria, Australia. Measurements of crown–rump length, head length, and head width were recorded every week from birth. Body weight was recorded weekly once the joeys were detached from the teat at 142 days of age, until 218 days of age. The growth curves revealed an initial linear increase in crown–rump lengths until approximately 60 days of age, when the gradient increased, while head length and head width showed a largely linear increase with age. The appearances of various morphological characteristics were also recorded. Zoo Biol 22:497–505, 2003. © 2003 Wiley‐Liss, Inc.  相似文献   

12.
The demographic history of 4 races or subspecies of leopard, Panthera pardus, was reviewed from international studbook records dating back to 1953. The Chinese leopard has been the most common pedigree race maintained in captivity, a factor linked to the length of time (29 years) this subspecies has been in captivity. The relative youth of the wild-born founders also helped them to adjust to captivity as well as live long reproductive lives. Today, however, this race is suffering from the ill effects of inbreeding due to the small founder size. This condition appears to be correctable now that additional specimens have been located. Persian leopards have a larger founder size than the former race, but some of their ancestors were older animals at the time of acquisition. Because of this, their potential fecundity was probably depressed from psychological problems related to adjustment and a shorter life span in captivity. Two founding females experienced pelvic deformities while young, and few of their cubs survived because they all had to be delivered via caesarian section. This procedure also shortened the reproductive life of the females involved because the owning zoos refrained from breeding the animals in the leopards' later years. Captive leopards appear to live longer than their wild counterparts, although precise data on wild populations is not available. In captivity many reach 12–15 years old, and exceptional individuals of several races have lived 20 years. Most captive-born leopards begin breeding when they are 3 years old and continue until they are 8–10 years old. Reproduction in females usually ceases at 12–14 years, although males have a longer reproductive life, with several successfully breeding when 19–20 years old.  相似文献   

13.
Cryptomys h. hottentotus occurs in mesic and semi-arid regions of South Africa. It lives in colonies ofup to 14 individuals, in which reproduction is limited to one ofthe largest males and the largest female in the colony.
Reproduction and details of colony size and the number of breeding animals in a colony are described for one complete and two incomplete field-captured colonies. One incomplete colony was kept in captivity for more than 3 years, whereas the complete colony was autopsied.
The social hierarchy of the common mole-rat is almost linear and has a value of 0.7 1 calculated from Landau's linearity index. Subordinate mole-rats weighed less than dominant mole-rats. The reproductive mole-rats are the dominant animals within the colony. The non-reproductive females rank lowest in the hierarchy.
Mating was not confined to a particular season, but occurred more frequently during the summer months. The alpha male initiated pre-copulatory behaviour. The gestation length is 55 to 66 days (n = 2). Two litters each of three pups were born to the colony during captivity. The pups were relatively altricial. They wandered out of the nest 5 days after birth, began to eat solids when 10 days old, and were fully weaned at 4 weeks. When 2 weeks old the pups began to spar with each other and with some of the adult colony members, but levels of aggression were never high. The pups did not disperse but were incorporated into the colony, this suggesting that C. h. hottentotus colonies are largely composed of related individuals.  相似文献   

14.
We examine and discuss evidence of contrasting differences in fertility patterns between captive and wild female chimpanzees, Pan troglodytes, as they age; in the wild females reproduce in their 40s, but captive studies suggest that menopause occurs around that time. Thus, despite the increased longevity generally observed in captive populations reproductive life span is shortened. We outline a hypothesis to explain the apparent differential pace of reproductive decline observed between wild and captive populations. The breeding schedules of captive primates may contribute to accelerated reproductive senescence because continuous cycling in captive animals results in early depletion of the ovarian stock and premature senescence. Available evidence supports the hypothesis that women with patterns of high oocyte loss experience earlier menopause. Chimpanzees in captivity live longer, and thus, similar to humans, they may experience follicular depletion that precedes death by many years. In captivity, chimpanzees typically have an early age at menarche and first birth, shorter interbirth intervals associated with short lactational periods as young mature faster, and nursery rearing, which allows mothers to begin cycling earlier. Variables typical of wild chimpanzee populations, including late age at menarche and first birth, long interbirth intervals associated with prolonged lactational periods, and a long period of female infertility after immigration, spare ovulations and may be responsible for the later age at reproductive termination. Finally, we describe and discuss the timing of specific reproductive landmarks that occur as female chimpanzees age, distinguishing between functional menopause (age at last birth) and operational menopause (end of cycling). Am. J. Primatol. 71:271–282, 2009. © 2008 Wiley‐Liss, Inc.  相似文献   

15.
This study investigates the relationships between plasma corticosterone concentrations and white cell counts in captive females of the viviparous lizard Egernia whitii during two phases of the reproductive cycle. Gestating and postpartum females were captured in the field and held in the laboratory for 4 weeks. Plasma corticosterone and progesterone concentrations and white blood cell counts were examined in blood samples taken at capture and after 24 h, 1 week, and 4 weeks in captivity. At 24 h after capture, plasma corticosterone concentrations in both groups had increased significantly compared with initial values but then returned to initial concentrations after 1 week in captivity and remained low in the 4 week samples. Plasma progesterone concentrations remained elevated in the gestating females until the week 4 sample, just prior to parturition. The hormone data suggest that capture and captivity did not represent a significant long-term stressor to these animals. The increase in plasma corticosterone concentration was associated with heterophilia in the differential leucocyte count in both groups of females. Lymphocyte numbers decreased only in gestating females, suggesting that reproductive status may influence the interaction between adrenal activity and immune function.  相似文献   

16.
One family group of common marmosets (Callithrix jacchus) maintained in captivity under natural environmental conditions (Natal, Brazil, 05°46'S, 35°12'W) was observed by focal sampling at two non-consecutive days per week during two non-consecutive pregnancies (pregnancy 1: the last 8 fortnights before parturition; pregnancy 2: the last 5 ones) and after parturition (4 fortnights for both). The hourly percentiles of the duration of self-grooming and allogrooming interactions of the reproductive pair were submitted to Cosinor analysis for the 24-h period (p ≤ 0.05). The reproductive female's progesterone was monitored by fecal collection twice a week between 7:00 h to 9:00 h. Levels of progesterone were determined by ELISA method. During pregnancy 1, all interactions of the reproductive pair showed a 24-h statistically significant period. However, after parturition this periodicity is not present in some behaviors of the reproductive male. This animal presents the 24-h periodicity only toward to the reproductive female, the subadult son and to the newborns. Hormonal levels of the reproductive female showed isolated increases above 100 ng/g at the second and third fortnight after parturition, but did not characterize ovulation. Between pregnancy 1 and 2, the family was increased by the birth of four animals. During pregnancy 2, a statistically significant 24-h period was find only in self-grooming of the reproductive male and female, and in the interactions between the reproductive pair. Also, in the interactions of the reproductive male with only one of the juvenile son. After parturition the reproductive female ovulated at the second fortnight and became pregnant again. At this time, those interactions still have a 24-h period, except in grooming directed to the juvenile son by the reproductive male. As in the first post-partum, grooming directed to the newborns showed statistically significant 24-h period. These results suggest that the reproductive pair performs 24-h rhythmic grooming interactions only with some animals, supposed to be the preferential grooming partners. Furthermore, the temporal grooming expression in common marmosets may be affected by the reproductive condition (progesterone levels) of the reproductive female, by the care of newborn after parturition and the group size.  相似文献   

17.
One family group of common marmosets (Callithrix jacchus) maintained in captivity under natural environmental conditions (Natal, Brazil, 05°46'S, 35°12'W) was observed by focal sampling at two non-consecutive days per week during two non-consecutive pregnancies (pregnancy 1: the last 8 fortnights before parturition; pregnancy 2: the last 5 ones) and after parturition (4 fortnights for both). The hourly percentiles of the duration of self-grooming and allogrooming interactions of the reproductive pair were submitted to Cosinor analysis for the 24-h period (p ≤ 0.05). The reproductive female's progesterone was monitored by fecal collection twice a week between 7:00 h to 9:00 h. Levels of progesterone were determined by ELISA method. During pregnancy 1, all interactions of the reproductive pair showed a 24-h statistically significant period. However, after parturition this periodicity is not present in some behaviors of the reproductive male. This animal presents the 24-h periodicity only toward to the reproductive female, the subadult son and to the newborns. Hormonal levels of the reproductive female showed isolated increases above 100 ng/g at the second and third fortnight after parturition, but did not characterize ovulation. Between pregnancy 1 and 2, the family was increased by the birth of four animals. During pregnancy 2, a statistically significant 24-h period was find only in self-grooming of the reproductive male and female, and in the interactions between the reproductive pair. Also, in the interactions of the reproductive male with only one of the juvenile son. After parturition the reproductive female ovulated at the second fortnight and became pregnant again. At this time, those interactions still have a 24-h period, except in grooming directed to the juvenile son by the reproductive male. As in the first post-partum, grooming directed to the newborns showed statistically significant 24-h period. These results suggest that the reproductive pair performs 24-h rhythmic grooming interactions only with some animals, supposed to be the preferential grooming partners. Furthermore, the temporal grooming expression in common marmosets may be affected by the reproductive condition (progesterone levels) of the reproductive female, by the care of newborn after parturition and the group size.  相似文献   

18.
Although heat shock proteins (Hsps) are primarily considered as being intracellular, this study identified the presence of Hsp72 in plasma from female Holstein-Friesian dairy cattle. Plasma samples were collected from the same animals at different ages and on different days after calving and accordingly divided into 5 age classes. The age classes were calves less than 235 days of age, young heifers between 235 and 305 days of age, older heifers between 305 and 560 days of age, cows early in lactation, and cows later in lactation. For a subsample of animals within each age class, replicate plasma samples were collected from 1 to 7 days apart to test whether the Hsp72 concentration levels are repeatable on this shorter timescale. Hsp72 was observed in plasma samples from animals of all 5 age classes. For animals with blood samples taken a few days apart, the repeatability (within age class) of the Hsp72 concentration was 0.52 +/- 0.06. Age and days from calving significantly affected the Hsp72 concentration level. The highest Hsp72 level was observed in older heifers (305-560 days of age). The repeatability of Hsp72 concentrations across age classes within animal was 0.22 +/- 0.06. High environmental sensitivity and negative genetic associations between production and health traits in this high-producing breed have been documented earlier. Hsp72 is believed to be strictly stress inducible, and the finding of Hsp72 in plasma indicates that even apparently healthy individuals may experience extrinsic or intrinsic stress (or both).  相似文献   

19.
The reproductive organs of logn-term captive females and of wild females of the western swamp tortoise, Pseudemydura umbrina , which were taken temporarily into captivity, were studied over several years by ultra-sound scanning. Pseudemydura umbrina , a critically-endangered species, is active during winter and spring when the ephemeral swamps it inhabits contain water and aestivates during summer and autumn (November to May/June) when the swamps are dry. The vitellogenic growth of ovarian follicles commences during aestivation in summer and continues during autumn and winter. The timing of the vitellogenic cycle is remarkably similar to that of many other Australian chelids and that of many other chelonians of temperate and subtropical regions, but the patterns of energy harvest, storage and allocation to ovarian follicles is different. Ovulation occurs between late September and early November and is preceded by a feeding bout and a sharp increase in female body mass. One clutch of 3–5 eggs (exceptionally of one or two) is laid in November/December. Sub-adult females show cycles of follicular growth, followed by atresia, for several years before ovulating and laying eggs. Females taken into captivity may miss the following vitelogenic cycle, but captivity does not generally affect vitellogenic cycles. Ovulation and egg production of captive animals is easily suppressed, however, under stress or sub-optimal food intake in spring. The sensitivity of ovulation to sub-optimal conditions and the subsequent reabsorption of the yolk material may enhance survival of the reproducing individual during long dry periods in an unpredictable environment.  相似文献   

20.
The present study investigates whether and how the pineal or its hormone melatonin influences female reproductive functions, namely the litter size, prenatal development of offsprings, and estrous cyclicity, especially its age-related cessation in a non-seasonal breeder, the laboratory rat. Wistar rats were maintained under a 24 h light-dark (12Lratio12D) cycle. Female rats were divided into 3 groups: non-operated (NO), sham-operated (SX), and pinealectomized (PX). Surgeries were performed in 35-40 day-old females. Starting at an age between 70 days and 7 months, female rats of all 3 groups were repeatedly mated with intact males. PX mothers more frequently delivered pups with malformations (e.g., taillessness, hydronephrosis, 7 out of 1263 pups) than control rats (0/1323; p<0.007). In the first delivery at 3 months of age, but not at later ages, PX mothers delivered more pups of lower body weight than control animals (p<0.001). Examination of vaginal smears showed that almost all female rats of the NO, SX, and PX groups had 4-day estrous cyclicity when they were young-between 60 days and 5 months of age. At an age of 17 to 18 months, most female rats of the NO and SX groups showed irregular, continuously diestrous or pseudopregnancy-like patterns, and 4-day estrous cyclicity was found in only 10% of the NO or SX animals. In contrast, about 50% of the PX rats showed 4-day estrous cyclicity at this older age (p< 0.001). Melatonin, when added to drinking water (0.4 mg/L) for 16 days during the dark phase increased the frequency of diestrous phase, except in continuously diestrous rats and very few others. This melatonin effect was strong in PX rats but relatively weak in SX rats. In conclusion, the pineal hormone appears to influence various reproductive functions and developmental processes, especially pregnancy and the timing of reproductive aging in rats. The effects of pinealectomy are more prominent at an age of 60 to 80 days (i.e., shortly after puberty) and at the beginning of the cessation of cycles in middle-aged females.  相似文献   

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