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1.
Flehmen is a behaviour characterized by an open mouth and the upper lip curled back and up. It is given by feral goats of both sexes. Males give flehmen most often in response to the urine of females, but also to their own urine and to the urine of other males. Females give flehmen and a related behaviour, riech-gähnen, after sniffing their own and unrelated neonates. Flehmen in the feral goat may function in the olfaction of a number of compounds, enabling males to assess oestrus in females and the relative condition of other males, and females to differentiate between their own and unrelated neonates. Two functional classes can be recognized: monitoring processes, involving regular, frequent testing, and discriminatory learning processes, involving relatively rare decision-making. It is emphasized that the relative frequency of flehmen in different contexts may not reflect its biological significance.  相似文献   

2.
本文研究了绵羊对不同品种公母羊的尿液、母羊粪便、阴道分泌物、身体的气味等刺激物诱导卷唇行为的发生,持续约60-120秒。实验得出:母羊尿液是诱导公羊释放卷唇行为最强的刺激物,尤以发情母羊尿液更甚,公羊、幼羊以及其它的尿液诱导卷唇行为发生的频次低。卷唇行为发生的频次有季节变化,10月最高。卷唇行为与犁鼻器的功能紧密联系,是绵羊繁殖行为的一个构成部分,通常只有公羊发生卷唇行为,但个别母羊亦有表现。  相似文献   

3.
We studied the relationship between increase in body weight and reproductive performance in different populations of Norwegian moose to evaluate costs associated with early onset of reproduction, viz. whether early onset of reproduction was correlated with low adult body weight or reduced adult fecundity. The mean carcass weight of non-ovulating yearlings was significantly lower than for ovulating yearlings. However, those 2.5 yr old females that conceived as yearlings were lighter than non-reproducing females of the same age. Thus, to begin to reproduce as a yearling was assumed to be expensive because it reduces the possibilities for further growth. The cost associated with reproduction was further illustrated by the fact that the difference in mean carcass weight from age 2.5 to 3.5 yr of females that produced calves in both years, was less for the females from regions with lowest mean yearling weights, i.e. regions with probably the lowest resource availability. In populations with high mean yearling carcass weights, the proportion of cows with calf and the number of calves per pregnant female in the early reproductive phase (2.5 or 3.5 yr old) were higher than in populations in which the mean yearling weights were low. There was a negative correlation between growth rate in the population after 1.5 yr of age and the mean yearling carcass weight. Thus, low yearling weight was associated with a prolonged period of growth and thereby a reduced reproductive output during the first year of the female's life. For old females (≥ 9.5 yr old) the number of calves produced per pregnant female was highest in populations where yearling carcass weights were highest. Furthermore, mean yearling weight and the mean adult female weight were positively correlated in those regions. This relationship suggests that within this species early onset of reproduction is not related to retarded reproduction or lower weight later in life. We suggest that the moose has been selected for an early onset of reproduction.  相似文献   

4.
Social interactions of adult female sable antelope, Hippotragus niger, were observed at the National Zoological Park's Conservation and Research Center. Aggressive behavior was quantified for two herds containing 8 and 11 females. Aggression was lowest at calving, and highest near the time of conception. Dominance hierarchies were strictly linear and stable over time. Dominance rank was highly correlated with age, with the oldest females achieving highest rank. High-ranking females initiated more aggression and were more likely to behave aggressively towards a newly introduced adult female. The newly introduced individual was the victim of prolonged, intense group chases and was permanently excluded from the herd. Low-ranking females directed more aggression at yearling herd members than did high-ranking females. Temporary absences by herd members resulted in long-lasting, substantial increases in received aggression upon their return. Because of their aggressive nature, sable antelope present a challenge to captive management. © 1993 Wiley-Liss, Inc.  相似文献   

5.
Introductions of sable antelope (Hippotragus niger) can be difficult due to the potential ensuing aggression compounded by their large horns. The goal was to use hormonal assays and behavioral analyses to evaluate the success of an introduction of 2 adult females at Lincoln Park Zoo. The objectives were to (a) document behavioral and hormonal changes in 2 female sable antelope during the introduction, (b) compare fecal glucocorticoid metabolites (FGM) in each individual during the introduction stages, (c) measure fecal androgen metabolites (FAM) during introduction and compare with dominance rank and observed aggression, and (d) monitor estrous cycle synchronization. Results demonstrate that FGM were higher before than during and after the introduction. Behavioral observations indicated limited aggression between females, although the keeper survey results revealed that the new female was more dominant and had higher mean FGM and FAM than the resident. Both sable antelope were reproductively active throughout the year. Results indicate that fecal hormone analysis can provide zoo management with valuable information to minimize the risk of aggression, injury, and stress during introductions of nonhuman animals.  相似文献   

6.
Introductions of sable antelope (Hippotragus niger) can be difficult due to the potential ensuing aggression compounded by their large horns. The goal was to use hormonal assays and behavioral analyses to evaluate the success of an introduction of 2 adult females at Lincoln Park Zoo. The objectives were to (a) document behavioral and hormonal changes in 2 female sable antelope during the introduction, (b) compare fecal glucocorticoid metabolites (FGM) in each individual during the introduction stages, (c) measure fecal androgen metabolites (FAM) during introduction and compare with dominance rank and observed aggression, and (d) monitor estrous cycle synchronization. Results demonstrate that FGM were higher before than during and after the introduction. Behavioral observations indicated limited aggression between females, although the keeper survey results revealed that the new female was more dominant and had higher mean FGM and FAM than the resident. Both sable antelope were reproductively active throughout the year. Results indicate that fecal hormone analysis can provide zoo management with valuable information to minimize the risk of aggression, injury, and stress during introductions of nonhuman animals.  相似文献   

7.
Lasting effects of conditions at birth on moose body mass   总被引:9,自引:0,他引:9  
Whether cohort effects can be retrieved in adult phenotypes depends on the possibility for individuals to compensate for a good or bad start in life. This ability to compensate may itself depend on the environment and on individual sex. In large polygynous ungulates, male reproductive success relies more on body size than the reproductive success of females, which makes them more sensitive to a bad start in life. Based on current theories of life history evolution and sexual selection, we tested the following predictions in a moose population: 1) cohort effects and year effects occur in both male and female adult body mass, but due to 2) compensatory growth, cohort effects tend to fade away with the individual's age; and 3) males are more sensitive to cohort effects than females. In support of the first prediction, we found that density and climate during the year-of-birth and the year-of-harvest affected moose body mass in both sexes. However, the magnitude of the effects of environmental conditions at birth on adult body mass decreased with increasing age, but less so in males than in females. Thus, as expected based on our third prediction, environmental conditions early in life were more influential on adult body mass of males compared to females. Such a result supports the existence of sex-specific life history tactics, with males maximising growth rate and females rather trading-off growth for reproduction.  相似文献   

8.
Flehmen behaviour in Welsh pony (Equus caballus) mares and foals living on pasture was observed during 807 h of focal sampling. A series of flehmens performed at one site was defined as a flehmen incident. Colts exhibited flehmen incidents and performed flehmen more frequently during an incident than did fillies or mares. Filies exhibited flehmen incidents more frequently than did mares, but did not flehmen more frequently during an incident. Colts exhibited a peak frequency of performing flehmen and of flehmen incidents during weeks 1–4 with a subsequent linear decrease in frequency up to weeks 17–20. Usually, flehmen occurred without the subject having had direct contact of the nostrils, lips, or tongue with a possible stimulant. Twenty-six per cent of the flehmen incidents occurred during or after urination by another pony. Seven per cent of the incidents occurred during or after urination by the pony showing flehmen.  相似文献   

9.
Soiled bedding and urine from adult female white-footed mice (Peromyscus leucopus) were tested for their capacity to inhibit reproduction of young females. Test animals were given either physical or airborne contact with soiled bedding from adult females, adult female urine, clean bedding, or water from 21 to 150 days of age. Results indicate that reproductive inhibition is due to an airborne pheromone emitted by the adult females as a component of their urine. In the second experiment, young female mice were exposed to an adult female for 0, 1, 3, 6, 12, 18, or 24 h/day from 21 to 150 days of age. Results from this experiment show that exposure to adult females of as little as 3 h/day was sufficient to cause reproductive inhibition to occur. This phenomenon has important implications in terms of both female-female reproductive competition and socially mediated population regulation.  相似文献   

10.
The energetic costs of reproduction have an important influence on the life histories of female primates. At present, however, the interplay of female reproductive state, food availability, and strategies aimed at maintaining energy balance has been described for only a few species, limiting our ability to understand intra- and interspecific variation in female life histories. We assessed how female mantled howlers (Alouatta palliata) are affected by reproductive seasonality, and whether they alter their behavior to cope with the energetic demands of reproduction. From August 2013 to July 2015 we measured the reproductive state, behavior (1100 h of focal animal observations), and energetic condition (312 urine samples collected for C-peptide analysis) of 7 adult females, and assessed food availability (weekly phenological sampling of 397 food trees). Female behavior did not vary with reproductive state or reproductive seasonality. There were, however, differences in how females responded to variation in food availability according to reproductive state. Cycling and gestating females spent more time feeding than lactating females, and cycling females less time resting than females in other reproductive states, when food was more available. C-peptide concentrations were unaffected by either individual or overall variation in reproductive state, except for cycling females, whose concentrations increased during periods of high food availability. The energetic condition of female mantled howlers is broadly maintained over different stages of reproduction, but is sensitive to variation in food availability.  相似文献   

11.
A male common hippopotamus (Hippopotamus amphibius) was observed giving a flehmen grimace on 14 occasions in July and August of 1998 at the Denver Zoo. Twelve instances of flehmen occurred after anogenital investigation of the female as she was exiting the pool. The two other instances of flehmen occurred in the terrestrial portion of the enclosure after the male examined samples of the female's freshly voided urine. The frequency of flehmen increased as the female approached estrus. Flehmen in common hippos may be an example of an evolutionary remnant. Zoo Biol 18:415–420, 1999. © 1999 Wiley‐Liss, Inc.  相似文献   

12.
Kim SY  Velando A  Torres R  Drummond H 《Oecologia》2011,166(3):615-626
Theories of ageing predict that early reproduction should be associated with accelerated reproductive senescence and reduced longevity. Here, the influence of age of first reproduction on reproductive senescence and lifespan, and consequences for lifetime reproductive success (LRS), were examined using longitudinal reproductive records of male and female blue-footed boobies (Sula nebouxii) from two cohorts (1989 and 1991). The two sexes showed different relationships between age of first reproduction and rate of senescent decline: the earlier males recruited, the faster they experienced senescence in brood size and breeding success, whereas in females, recruiting age was unrelated to age-specific patterns of reproductive performance. Effects of recruiting age on lifespan, number of reproductive events and LRS were cohort- and/or sex-specific. Late-recruiting males of the 1989 cohort lived longer but performed as well over the lifetime as early recruits, suggesting the existence of a trade-off between early recruitment and long lifespan. In males of the 1991 cohort and females of both cohorts, recruiting age was apparently unrelated to lifespan, but early recruits reproduced more frequently and fledged more chicks over their lifetime than late recruits. Male boobies may be more likely than females to incur long-term costs of early reproduction, such as early reproductive senescence and diminished lifespan, because they probably invest more heavily than females. In the 1991 cohort, which faced the severe environmental challenge of an El Ni?o event in the first year of life, life-history trade-offs of males may have been masked by effects of individual quality.  相似文献   

13.
1. The energy available for reproduction is usually limited by resource acquisition (i.e. condition). Because condition is known to be strongly affected by environmental factors, reproductive investments also vary across heterogeneous environments. 2. Although the condition dependence of reproductive investment is common to both sexes, reproductive traits may exhibit sexually different responses to environmental fluctuation due to sex‐specific life‐history strategies. However, few direct experimental studies have investigated the condition dependence of reproductive investments in both sexes. 3. We investigated the condition dependence of life‐history and reproductive traits of males and females in the beetle Gnatocerus cornutus Fabricus by manipulating larval and adult diet quality. We found that male and female life‐history traits exhibited similar responses to environmental fluctuations. 4. By contrast, the sexes exhibit different patterns of condition dependence in reproductive traits (i.e. the adult nutritional environment has a strong impact on the female lifetime reproductive success, whereas larval nutritional environment strongly affects the secondary sexual trait in males). 5. This difference in the plasticity of reproductive traits may lead to different selection pressures for each sex, even if both sexes develop and/or live in the same environment.  相似文献   

14.
1. Trade-offs between reproduction and growth are central assumptions of life-history theory, but their implications for sexual size dimorphism (SSD) are poorly understood. 2. Adult male Yarrow's spiny lizards Sceloporus jarrovii average 10% larger than adult females. In a low-altitude (1700 m) population, this SSD develops because males grow more quickly than females during the first year of life, particularly during the first female reproductive season. This study tests the hypothesis that SSD develops because female growth is constrained by energetic costs of reproduction. 3. To test for a growth cost of reproduction, I compared growth rates of free-living females that differed, either naturally or experimentally, in reproductive status. Females that naturally delayed reproduction until their second year grew more quickly than females that reproduced as yearlings, and ovariectomized yearlings grew more quickly and to larger sizes than reproductive controls. 4. To determine whether SSD develops in the absence of this inferred reproductive cost, I also studied a high-altitude (2500 m) population in which all females delay reproduction until their second year. Sex differences in growth trajectories were similar to those observed at low altitude, such that males averaged 10% larger than females even prior to female reproduction. 5. Although female growth may be constrained by reproduction, multiple lines of evidence indicate that this cost is insufficient to explain the full magnitude of SSD in S. jarrovii. First, differences in growth of reproductive and nonreproductive females are not observed until the final month of gestation, by which time SSD is already well developed. Second, the growth benefit accruing from experimental inhibition of reproduction accounts for only 32% of the natural sex difference in body size. Finally, SSD develops well in advance of female reproduction in a high-altitude population with delayed maturation.  相似文献   

15.
Age at first reproduction is an important determinant of individual variation in reproductive success in ungulates, but few studies have examined its relationship with later fitness‐related traits in males. We used a long‐term individual based study of a harvested moose population to quantify the individual reproductive performance and survival of males, as well as to examine the determinants of age at first reproduction and consequences of age at first reproduction on lifetime breeding success. The probability that a male successfully reproduced at the age of two was negatively related to the mean age of adult males in the population, but the relationship weakened with increasing population size. Large antlers and large body mass relative to other males in the population increased the number of calves sired at their first successful mating season. In addition, those that successfully reproduced as two year‐olds were more likely to sire calves the next year, making them more productive at a given age compared to those that first reproduced at the age of three or older. We emphasize the importance for males to start reproducing as soon as possible in a harvested population to gain lifetime fitness benefits, as surviving the hunt is a major determinant of reproductive success in this population. We found no costs of early reproduction in males, hence leading to high individual heterogeneity in male reproductive performance. The apparent lack of reproductive costs could partly be explained by the age distribution in the population, individual variation in early‐life body mass and antler size, and differences in probabilities of being hunted of successful and unsuccessful males.  相似文献   

16.
The mechanism of senescence is an important subject of current research, but our knowledge of the factors influencing the rate of ageing in naturally occurring populations remains rudimentary. Evolutionary theories of senescence predict that investment in reproduction in early life should come at the cost of reduced somatic maintenance and thus result in earlier or more rapid senescence. We use data on the complete reproductive histories of 431 Common Blackbirds (222 males and 209 females) collected during a 19‐year study of the ecology of an urban population of this species to test the main hypotheses addressing the issue of senescence. On average, the birds in this population survived for 3.7 (± 1.9 sd) years. Reproductive success in females peaked at the age of 4, but in males remained stable until the 5th year of life. We observed declines in reproductive success, indicative of senescence, after the peak years in both sexes. The mechanism of age‐related changes in the reproduction of females confirms the individual improvement and selective disappearance hypotheses. In the case of males, the increase in reproductive performance comes as a consequence of the disappearance of poor reproducers. The parental investment associated with early life fecundity (the first two breeding seasons in males and females) impairs the breeding success of females later on. Contrary to expectations, there was no negative impact of high early life fecundity on either mortality or lifespan. Individuals of both sexes with a high early life fecundity had a higher lifetime reproductive success than those in which early life fecundity was low. Hence, the most profitable strategy is to maximize reproductive effort in the early stages of life. This yields the highest lifetime reproductive success, despite the increased impact of senescence, especially in females. These results are consistent with the disposable soma hypothesis.  相似文献   

17.
The age, growth and reproduction ofRutilus lemmingii (Steindachner, 1866), an endemic cyprinid from the Iberian Peninsula, was studied for over a period of two years in a small seasonal tributary of the Guadalquivir river basin. Approximately 65 % of the total growth in length occured in the first year of life. Males reached a maximum age of 3+ yr (Fork Length, F.L. = 114 mm) and females 4+ yr (F.L. = 144 mm). Both sexes matured during their second year of life (1 +). The overall sex ratio (334 males to 389 females) differed significantly from unity. Somatic condition decreased markedly during the reproductive period of March to May.R. lemmingii is a multiple spawner and releases two batches of eggs per female each year. Mean egg diameter of the first batch was larger than the second one. The regression between fecundity and Fork Length (mm) was: Fec = 0.014 F.L.Z.2.858 Compared with available information, thisR. lemmingii population, located at a lower latitude, is characterized by fast growth, early maturity, high level of reproductive effort, and a short life-span. These life-history characteristices are typical of species in unstable environments, where adult mortality is high, variable or unpredictable.  相似文献   

18.
SUMMARY. Growth increments, moult frequency and growth rates of individuals in a population of the freshwater crayfish Austropotamobius pallipes were followed for a period of 3 years during a mark-recapture study. There was an inverse relationship between body size and the growth increment relative to body size. The absolute increment increased from the juvenile to the young adult stage and thereafter declined with increasing body size.
Differences between the adult male, reproductive female, non-reproductive female and juvenile subpopulations in the size of growth increments are reported and growth increments during the two major moult periods of each year are compared. The effect of the endoparasite Thelohania contejeani and of chela regeneration was to reduce slightly the growth increments.
Instantaneous growth rates declined throughout life in both sexes, but adult males maintained higher growth rates than adult females, particularly in the largest size class studied. The effect of reproduction on growth appeared to be most severe in the smallest breeding females. Males maintained the tendency to moult twice annually to a larger size than females. A simplified construction of the relationship between size and age in the population is presented for each sex. The oldest animals were estimated to be at least 11 years old.  相似文献   

19.
In species with complex life cycles, life history theory predicts that fitness is affected by conditions encountered in previous life history stages. Here, we use a 4‐year pedigree to investigate if time spent in two distinct life history stages has sex‐specific reproductive fitness consequences in anadromous Atlantic salmon (Salmo salar). We determined the amount of years spent in fresh water as juveniles (freshwater age, FW, measured in years), and years spent in the marine environment as adults (sea age, SW, measured in sea winters) on 264 sexually mature adults collected on a river spawning ground. We then estimated reproductive fitness as the number of offspring (reproductive success) and the number of mates (mating success) using genetic parentage analysis (>5,000 offspring). Sea age is significantly and positively correlated with reproductive and mating success of both sexes whereby older and larger individuals gained the highest reproductive fitness benefits (females: 62.2% increase in offspring/SW and 34.8% increase in mate number/SW; males: 201.9% offspring/SW and 60.3% mates/SW). Younger freshwater age was significantly related to older sea age and thus increased reproductive fitness, but only among females (females: ?33.9% offspring/FW and ?32.4% mates/FW). This result implies that females can obtain higher reproductive fitness by transitioning to the marine environment earlier. In contrast, male mating and reproductive success was unaffected by freshwater age and more males returned at a younger age than females despite the reproductive fitness advantage of later sea age maturation. Our results show that the timing of transitions between juvenile and adult phases has a sex‐specific consequence on female reproductive fitness, demonstrating a life history trade‐off between maturation and reproduction in wild Atlantic salmon.  相似文献   

20.
The response of dairy bulls to the urine of cows in various stages of the reproductive cycle was quantified by presenting 200 ml of urine in a stainless steel bowl to the stanchioned bulls for 10 min. Estrous mucus was also presented in the same manner. Sniffs, nose licks and flehmen responses were recorded. Of 15 bulls tested only 7, or 47%, met the criteria of two flehmens in response to estrous urine. Among these bulls, the rate of flehmen was higher to estrous urine 6.1 +/- 1 flehmen/10 min) than to nonestrous urine (3.5 +/- 0.6 flehmen/10 in, paired t = 3.1, P < 0.03). Flehmen duration was also longer in response to estrous urine (6.4 +/- 0.4 sec) than to nonestrous urine (5.7 +/- 0.4 sec, t = 2.65, P < 0.03). There were no significant differences between the sniff frequencies and durations or in the number of licks to estrous and diestrous urine. There were significantly more flehmen responses to estrous urine (7 +/- 1.4 10 min ) than to mucus (2.25 +/- 0.9 10 min , t = 4.75, P < 0.01). The response to water (0.6 +/- 0.3 10 min ) was not different from that to mucus (t = 2.37, P < 0.10). The spontaneous flehmen rate of dairy bulls in their home stalls was 3.2 +/- 0.7 24 h . Although estrous cows did not exhibit flehmen frequently, they did sniff bull urine more frequently (3.6 +/- 0.6 10 min ) than nonestrous cows (1.8 +/- 0.3 10 min , t = 2.4, P < 0.03).  相似文献   

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