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Material from kudu shot on tsetse control was studied for information on breeding and feeding habits. A number of animals was measured and weighed, illustrating that males were bigger than females.
Field observations and stomach contents showed that the species is mainly a browser eating a wide variety of plants.
A marked peak of calving was observed and this coincided with the tall grass season (January-April), when the newly-born young are apparently hidden. Kudu in the area studied may be solitary but are generally associated in small groups of about four, although as many as eleven have been seen together in the study area.  相似文献   

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The effect of three pleasant fine women's fragrances on the mood of women was assessed. The three fragrances had similar hedonic values but different sensory characteristics. The fragrances elicited nonspecific effects on mood. All three fragrances’ impact on mood was influenced by initial mood and lasted up to three hours, i.e., as long as the scent was still noticeable. Trends revealed that all three fragrances decreased negative affect and increased vigor. Also, independent of their hedonic value, the three fragrances elicited specific mood patterns. With the “woody citrus coniferous” scent, respondents experienced higher hostility and tension. The “floral chypre citrus” fragrance decreased anger and confusion. The “floral woody” scent had the lowest Total Mood Disturbance score and lowered depression, tension and confusion.  相似文献   

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范志勤 《生态学报》1982,2(3):285-290
各种环境刺激是通过机体调节动物繁殖的重要因素。近来研究逐步揭示了化学信息在鼠类繁殖中的刺激作用(范志勤,1981;Bronson,1971;Parkes et al.1961;Whitten,1966)。一般将哺乳动物的化学信息分为信号外激素和诱导外激素。前者指经短时间的刺激,经由中枢神经系统,引起受纳动物直接的行为反应的一类外激素;后者通过神经一激素的调节诱导感受动物产生相对持久的生理状况和机能的变化。信号外激素的特点是作用时间短、行为变化快,反应可逆,即在刺激消失后,行为反应亦形消失。那么诱导外激素则表现  相似文献   

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Natural animal populations are adapted to and in equilibrium with their natural environment. Sudden changes in composition of flora or fauna of climax communities may cause serious consequences and even the collapse of the system. This is especially true in Africa where shallow soil and precarious energy cycles are easily upset. With this in mind, it is suggested that serious consideration be given in tsetse-control schemes and land-use plans to the feasibility of game-farming, especially when marginal lands are involved. It would be advantageous in many instances to keep all large and some smaller tracts of marginal lands for wildlife conservation purposes; the large areas as national parks and as a valuable source of government income and prestige, the smaller areas as a permanent animal-protein supply through game-harvesting operations. The advantages of game-farming over domestic livestock-raising are discussed in detail. A schematized tsetse-control plan is also presented as an example of land-use in savannah tsetse belts.  相似文献   

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本文通过考察普通野生稻(Oryza rufipogon)实验种群对不同频度刈割的反应,揭示刈割对该种群的密度、株高、生物量、单枝生物量和有性生殖份额等有明显的抑制作用,对累积株高增长和光合系统份额则有一定的促进作用。刈割频度越大,作用越大。但对后两者的促进是以消耗地下部分的物质和能量为前提的,超过一定频度的刈割不仅可使其有性生殖份额降至零,还可导致种群消亡。提示过频破坏普遍野生稻地上部分是该种部分种群发生地方性绝灭的重要原因之一。  相似文献   

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多巴胺能药物对鲤鱼促性腺激素分泌活动的影响   总被引:7,自引:0,他引:7  
王黎  林浩然 《动物学报》1997,43(1):74-79
研究多巴胺(DA)及其激动剂阿扑吗啡(APO)和拮抗剂Domperidone(DOM)对不同性腺发育时期和不同年龄雌鲤促性腺激素(GtH)分泌活动的影响。结果表明:鲤鱼基础GtH分泌具有明显的季节性变化,表现为血清GtH含量在性腺发育早期较低,性腺成熟期升高,到性腺退化期又降低。DA和APO对GtH分泌的抑制作用及DOM对GtH分泌的刺激作用在不同性腺发育时期为:性腺发育早期〉性腺成熟期〉性腺退化  相似文献   

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Weights of 173 non-pregnant female elephants whose ages were estimated from the degree of molar tooth wear (Laws, 1966) were used to construct a growth curve. This differed from the growth curves described by Laws (1966) and Laws and Parker (1968), and reasons are suggested for this discrepancy.  相似文献   

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Timothy O.  Osborne 《Ibis》1981,123(3):289-297
The Red-necked Falcon in southern Zambia is a year-long resident in its breeding territory. The study was conducted on a floodplain and the adjacent acacia savannah in an undisturbed natural environment. The falcon principally nests in natural depressions on frond bases on the leeward side of Borassus Palms but also utilizes old crow and raptor nests. Incubation averaged 33 days and was undertaken by the female. The young fledged after a 36-day nestling period and remained under parental care for up to three weeks after that. Nesting success averaged 1.3 young per nest or 44% of the eggs laid. The post-juvenal moult commenced when the young were five to six months old and continued for six months. Birds comprised 98% of the diet of the falcons. The adults selected larger prey as the nestlings increased in size. The 69-day incubation and nesting period is up to 14 days longer than in similar-sized falcons.  相似文献   

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Treatment of Nitella antheridia with colchicine results in various sperm abnormalities, depending upon duration of exposure and subsequent recovery. Early effects of treatment include disappearance of spindle fibers and a cessation of ordered cell wall formation in dividing cells. Sperm released from antheridia treated for 24 hr and allowed to recover for 4–5 days possess branched flagella. After a recovery period of 6–10 days the sperm appear normal; however, following longer recovery periods, the sperm exhibit variations in size and number of flagella. Branched flagella contain a variety of microtubule patterns ranging from branches containing a single microtubule to flagella with an excess of microtubules. Spermatids which differentiate in the presence of colchicine lack flagella and a microtubular sheath. Nuclear contents undergo condensation stages; however, the nucleus as a whole does not undergo the orderly elongation and coiling characteristic of untreated Nitella spermatids. Long-term colchicine treatment followed by a recovery period produces atypical microtubules and microtubular aggregations in the spermatid. The results indicate that colchicine affects not only polymerization of microtubule subunits but also factors responsible for their ordered spatial relationships in the cell. The presence of microtubules is a prerequisite for normal morphological changes during spermiogenesis.  相似文献   

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