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1.
During 5 years of observation in a cat colony where mating tests are routinely conducted, the spontaneous occurrence of distortions of sexual activity in male cats has been recorded. Many of the behavioral patterns encountered have previously been described only in brain-damaged animals when they have been used as an index of "hypersexuality." Identical behavior occurs in normal males as a simple training effect.  相似文献   

2.
Theory on the evolution of ornamental male traits by sexual selection assumes consistency in selection over time. Temporal variation in female choice could dampen sexual selection, but scant information exists on the degree to which individual female preferences are flexible. Here we show that in lark buntings sexual selection on male traits varied dramatically across years and, in some cases, exhibited reversals in the direction of selection for a single trait. We show that these shifts are probably because of flexibility in mate choice by individual females and that they parallel shifts in the male traits that predict female reproductive success in a given year. Plasticity in choice and concomitant reversals in mating patterns across time may weaken the strength of sexual selection and could maintain genetic variation underlying multiple sexual ornaments.  相似文献   

3.
栾多态毛蚜生活周期的研究   总被引:1,自引:0,他引:1  
牛延鹏 《农技服务》2009,26(2):48-49
蚜虫的生活周期十分复杂,可以分为不全周期和全周期。全年孤雌生殖,不发生性蚜世代的,称为不全周期。在1~2年内,一般在一年内有孤雌生殖与两性生殖世代交替的,称为全周期。全周期还可以根据转移情况分为几个类型。了解这些类型,可以对蚜虫的生活习性有一简明概念,有利于进行观察研究和防治。该试验着重对栾多态毛蚜(Periphyllus koelreuteriae)的生活周期进行了详尽研究。栾多态毛蚜生活周期属于全周期类型。它有其自身的特殊性,尤其是越夏小型蚜的出现,更是对不良外界环境的一种适应表现。  相似文献   

4.
对网箱养殖条件下黄鳝性腺指数进行测定并观察性腺组织切片,结果发现:网箱养殖条件下黄鳝在1周年内可以达到雌性性成熟,即网箱养殖条件下雌性黄鳝初次性成熟年龄为1龄;网箱养殖条件下1周年内黄鳝的性腺指数大致呈增长趋势,在6月,性腺发育成熟时,性腺指数达最大值,其值为14.33±2.07;网箱养殖黄鳝在1周年内血清雌二醇质量浓度在6月达到最大值,即(1 233.52±126.07)pg/mL,血清睾酮质量浓度在5月已经达到最大值,即(13.99±1.54)pg/mL。  相似文献   

5.
Transmammary infection of newborn by larval trematodes   总被引:1,自引:0,他引:1  
Newborn cats and mice became infected with Alaria marcianae if they nursed from females that had been experimentally infected with the parasite. All lactating females showed mesocercarial stages in their mammary glands. This may be the first trematode found to undergo transmission through the mammary glands under experimental conditions. Similarities in the behavior of mesocercariae in humans and in the mouse suggest that an infected human female might infect her infant if she elected to nurse it.  相似文献   

6.
The presence of a sex chromatin body similar to that reported in other tissues has been demonstrated in the nuclei of osteoblasts, osteocytes, and periosteal cells from female dogs and cats.  相似文献   

7.
The male of Calopteryx maculata (Beauvois) (Odonata) uses its penis not only to transfer sperm to the female but also to remove sperm deposited in the female's sperm storage organs from previous matings. Apparently, no such sperm removal function has previously been attributed to the intromittent organ of any animal.  相似文献   

8.
本文报道了落叶松绶尺蠖(ZetheniarufescentariaMotschulsky)的生物学特性及生活史。此虫在黑龙江省1年一代,以蛹在枯枝落叶层下越冬,多危害郁闭度较大的落叶松人工林,尤以中龄林受害最重,成虫子5月下旬为羽化始盛期,6月3日左右为羽化盛期,7月13日左右羽化结束。雌雄比为1:1.1。成虫羽化后即交尾,交尾时间一般在23时以后,卵多产在落叶松枝条上,少数产在针叶及树皮缝里。雌蛾平均产卵量为58.6粒。雄虫寿命平均3.9d,雌虫平均寿命5.6d。幼虫共6龄,子8月上旬开始化蛹,8月下旬化蛹结束。  相似文献   

9.
黄鳝精巢发育的周年变化   总被引:3,自引:0,他引:3  
对黄鳝精巢显微和超微结构的观察结果表明 ,其精原细胞可分两种类型 :初级精原细胞和次级精原细胞 ;精子鞭毛轴丝由外周 9组微管和两根中央微管构成 ;间质细胞分布有广泛的滑面内质网和具小管的线粒体。据对10 6尾 (体重为 17~ 32 0 g)黄鳝精巢切片观察 ,黄鳝由雌性完全转变为雄性后 ,精巢已接近发育成熟 ;经 χ2 检验表明 ,其性腺成熟度与体重关系不大 (P >0 0 5 )。性成熟后 ,精巢所处发育阶段 (Ⅰ -Ⅵ期 )主要随不同季节而变化  相似文献   

10.
DNAs of the two mating-type alleles of Neurospora crassa are highly dissimilar   总被引:16,自引:0,他引:16  
The mating-type alleles A and a of Neurospora crassa control mating in the sexual cycle and function in establishing heterokaryon incompatibility in the vegetative cycle. The A and a alleles were cloned, and they were shown to encode both the sexual functions and vegetative incompatibility. The mating-type clones contain nonhomologous DNA segments that are flanked by common DNA sequences. Neurospora crassa and all heterothallic and pseudohomothallic Neurospora species contain a single copy of one mating-type sequence or the other within each haploid genome. The six known self-fertile homothallic isolates contain an A homolog, but only one species also contains a homologous sequences. Homothallism in these species is not due to mating-type switching, as it is in Saccharomyces cerevisiae.  相似文献   

11.
对西农莎能山羊4个年度繁殖的23头间性羊从解剖学、组织学和细胞遗传学三方面研究,发现了各种类型的间性羊,其中性逆转雄性间性及拟雌性假间性属山羊中首次提出的间性类型。它们的性染色体全部是XX型(遗传雌性)。因而间性基因是雄性化基因,使雌性个体向雄性转化。通常所见的异常雄性:短阴茎和性逆转雄性间性(包括小睾丸)是遗传雌性个体。  相似文献   

12.
Animal germ cells differentiate as sperm or eggs, depending on their sex. Somatic signals tell germ cells whether they reside in a male or female body, but how do germ cells interpret those external cues to acquire their own sexual identity? A critical aspect of a germ cell's sexual puzzle is that the sperm/egg decision is closely linked to the cell-cycle decision between mitosis and meiosis. Molecular studies have begun to tease apart the regulators of both decisions, an essential step toward understanding the regulatory logic of this fundamental question of germ cell biology.  相似文献   

13.
研究不同类型杂交蓖麻F2代雌性单株的主穗性别可逆转性、有效分枝数、主穗长度、百粒重对选育效果的影响。试验结果表明:在主穗性别可逆转性和有效分枝数、主穗长度这两个性状上,3个参试材料比CK都极显著性。但在百粒重性状上,CSR8-5×OUC-5的F2代雌性单株比CK不显著,CSR8-5×DH-7的F2代雌性单株还极显著差于CK。通过对不同类型杂交蓖麻F2代雌性单株选育,筛选适应华南地区的综合性状的蓖麻F2代优良雌性单株。  相似文献   

14.
Sexual selection may explain why secondary sexual traits of males are so strongly developed in some species that they seem maladaptive. Female mate choice appears to favor the evolution of conspicuous color patterns in male guppies (Poecilia reticulata) from Trinidad, but color patterns vary strikingly among populations. According to most theory, correlated evolution of female mating preferences and preferred male traits within populations could promote this kind of divergence between populations. But mating preferences could also constrain the evolution of male traits. In some guppy populations, females discriminate among males based on variation in the extent of orange pigment in male color patterns, and populations differ significantly in the degree offemale preferences for orange area. In a comparison ofseven populations, the degree offemale preference based on orange is correlated with the population average orange area. Thus male traits and female preferences appear to be evolving in parallel.  相似文献   

15.
新疆两种星翅蝗外生殖器的比较研究   总被引:1,自引:0,他引:1  
对意大利蝗、黑腿星翅蝗两种星翅蝗雄性外生殖器、雌性下生殖板进行比较解剖,并描述其形态特征。结果表明,两种星翅蝗雄性外生殖器变化最为明显的部位是阳具基背片的侧板及阳具复合体的色带基支、色带瓣、阳茎端瓣。两种星翅蝗雌性下生殖板变化最为明显的部位是下生殖板的前突基内支及腹产卵瓣腹基瓣片。外生殖器特征在意大利蝗和黑腿星翅蝗存在明显差异,可作为两种蝗虫区别性状。  相似文献   

16.
Heterothallism in biflagellate aquatic fungi: preliminary genetic analysis   总被引:1,自引:0,他引:1  
Genetic analysis of several hundred progeny from crosses of two heterothallic species of Achlya and Dictyuchus provides preliminary information about the life cycle and pattern of sexuality in the biflagellate Phycomycetes. Extensive testing of mycelial progeny indicates a diploid life cycle. Control of sexual expression and mating competence appears to be based on a complex genetic system.  相似文献   

17.
笼养川金丝猴雌性性行为的研究   总被引:12,自引:1,他引:11  
采用全事件抽样法和瞬时扫描技术,对7只5~17岁的雌性金丝猴进行为期348d,共计3745h的观察。结果表明,雌川金丝猴具爬跨行为;邀配行为有两种方式;交配时雌猴或爬伏或四肢站立;交配活动受顺位影响,优先程度可用优先指数衡量;交配后雌性行为多样化。交配频度具有波动性。  相似文献   

18.
Saccharin preference and performance in a Lashley III maze were found to be altered in adult male and female rats that had been exposed to alcohol during gestation. Specifically, the sexual dimorphism normally observed in both behaviors was absent in fetal alcohol-exposed animals. The lack of sexual dimorphism appeared to result from a masculinization of the exposed females and a feminization of the exposed males.  相似文献   

19.
DARPP-32, a dopamine- and adenosine 3',5'-monophosphate (cAMP)-regulated phosphoprotein (32 kilodaltons in size), is an obligate intermediate in progesterone (P)-facilitated sexual receptivity in female rats and mice. The facilitative effect of P on sexual receptivity in female rats was blocked by antisense oligonucleotides to DARPP-32. Homozygous mice carrying a null mutation for the DARPP-32 gene exhibited minimal levels of P-facilitated sexual receptivity when compared to their wild-type littermates. P significantly increased hypothalamic cAMP levels and cAMP-dependent protein kinase activity. These increases were not inhibited by a D1 subclass dopamine receptor antagonist. P also enhanced phosphorylation of DARPP-32 on threonine 34 in the hypothalamus of mice. DARPP-32 activation is thus an obligatory step in progestin receptor regulation of sexual receptivity in rats and mice.  相似文献   

20.
黄曲条跳甲成虫生殖系统的解剖学观察   总被引:1,自引:0,他引:1  
对黄曲条跳甲雌雄成虫生殖系统进行了解剖学观察。结果表明:雌成虫的生殖系统由1对卵巢、1对侧输卵管、中输卵管、交配囊、受精囊、生殖腔和产卵器组成;雄成虫生殖系统由睾丸、1对输精管、1对附腺、射精管和阳茎组成。雌成虫的每个卵巢有卵巢管8-12条,每条卵巢管有卵7-10粒,卵巢内的总卵数在112-240粒。雄成虫腹部和阳茎具有向内弯曲等特点,有利于交配成功。  相似文献   

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