Male Esterase 6 Catalyzes the Synthesis of a Sex Pheromone in Drosophila melanogaster Females

Esterase 6, a component of the seminal fluid of Drosophila melanogaster males, hydrolyzes cis-vaccenyl acetate, a lipid made only by males, to cis-vaccenyl alcohol. This reaction occurs in the female reproductive tract and is virtually complete within 6 hours after copulation. Both the alcohol and the acetate decrease the number of matings among pairs of virgin flies in which the female is treated topically with these substances. Although females tested 10 minutes after copulation elicit less courtship than virgin females, females tested 6 hours after copulation stimulate even less courtship if they received active esterase 6 in the seminal fluid of their respective mates. Either the alcohol or a derivative appears to be an antiaphrodisiac that decreases courtship elicited by inseminated females and thus reduces the probability of further mating. Thus the activity of the pheromone depends on a final reaction which occurs in the female, using both substrate and enzyme provided by the male.     

蝇蛹金小蜂的交配行为及雄蜂交配次数对雌蜂繁殖的影响

多数昆虫能够进行多次交配,随寄生蜂雄蜂交配次数的增加,雄蜂体内精子减少,雌蜂获得的精子数量减少,产下更多的单倍体卵,发育为雄性后代;一些单寄生性的寄生蜂雌蜂一生仅能够交配1次。描述了蝇蛹金小蜂雌雄蜂的交配行为,探讨了雄蜂交配次数对雌蜂后代产量等的影响以及雌蜂的可交配次数。结果表明,交配过程包括求偶、交尾前期、交尾和交尾后期;雄蜂已交配的次数并不能够显著影响其配偶的寿命、产卵期和后代总数量,但显著影响到其配偶的雌、雄后代数量和性比。随雄蜂交配次数的增加,与之交配的雌蜂的后代雄性百分比显著增大,雌蜂在产卵期内更早地出现较多雄性后代,体内精子不足的现象更加明显。无论已交配的蝇蛹金小蜂雌蜂在产卵期中是否出现精子不足,均不能再次完成交配。     

Inbreeding promotes female promiscuity

The widespread phenomenon of polyandry (mating by females with multiple males) is an evolutionary puzzle, because females can sustain costs from promiscuity, whereas full fertility can be provided by a single male. Using the red flour beetle, Tribolium castaneum, we identify major fitness benefits of polyandry to females under inbreeding, when the risks of fertilization by incompatible male haplotypes are especially high. Fifteen generations after inbred populations had passed through genetic bottlenecks, we recorded increased levels of female promiscuity compared with noninbred controls, most likely due to selection from prospective fitness gains through polyandry. These data illustrate how this common mating pattern can evolve if population genetic bottlenecks increase the risks of fitness depression due to fertilization by sperm carrying genetically incompatible haplotypes.     

Decay of female sexual behavior under parthenogenesis

A laboratory strain of Drosophila mercatorum has existed for 20 years without males and therefore without natural selection operating to maintain the genetic basis of female mating behavior. The females of this strain have recently experienced a genetic impairment of mating capacity. This observation exemplifies the mode of evolution of vestigial characters and supports Muller's theory that random mutation will tend to destroy the genetic basis of a character from which selection has been removed.     

Mating Behavior and Related Morphological Specialization in the Uropodine Mite, Caminella peraphora

Sperm transfer in Caminella peraphora is closely associated with secretion and construction of a female-associated structure, the signet ring. The ventral portion of the ring serves as an external spermatheca early in mating. Although sperm assimilation occurs prior to development of the dorsal ring elements, male participation is instrumental in successful ring completion.     

青蛤的受精细胞学观察

采用常规石蜡切片方法,用苏木精-伊红染色,在光学显微镜下观察青蛤Cyclina sinensis卵子受精和第一次卵裂的过程。青蛤的成熟卵处于第一次成熟分裂中期,此时可以接受精子入卵即受精。在水温23.2℃条件下,精卵混合6 min时精子开始入卵;混合15 min时,受精卵开始排出第一极体;混合21 min时,受精卵开始排出第二极体;雄原核在第二极体释放前形成,第二极体释放后很快形成雌原核,雌、雄原核逐渐在中央靠拢;42 min时,雌、雄原核融合成合子;50 min左右时,受精卵完成第一次卵裂,成为两个细胞。     

烟蚜茧蜂的交配行为研究

[目的]明确烟蚜茧蜂的交配行为,探讨雌蜂传递的线索对引发雄蜂交配行为的作用,为烟蚜茧蜂的规模化繁殖和应用提供理论基础.[方法]在室内显微镜下和温室繁蜂棚内直接观察烟蚜茧蜂的交配行为,设死亡处女雌蜂(n=19)、碾碎的雌蜂腹部(n=15)、接触过处女雌蜂的滤纸(n=15)、仅提供雌蜂视觉线索(n=20)和空白对照(n=20)5个不同的试验处理,观察雌蜂传递的嗅觉和视觉线索对引发雄蜂求偶行为的作用.[结果]雄蜂交配行为包括接近、求偶、爬背、敲打触角、交配试探、插入、交配、分离,处女雌蜂交配行为包括逃跑和拒绝交配或接受交配、交配、休息.雄蜂与处女雌蜂的交配过程可划分为搜寻和求偶、交配前期、交配和交配后期4个阶段,且试图交配的雄蜂求偶成功后一般能够与处女雌蜂完成整个交配过程.雄蜂会试图与交配过的雌蜂、死亡的雌蜂发生交配行为,但仅出现交配前期.接触过活体处女雌蜂的滤纸和压碎的雌蜂腹部能够引发雄蜂强烈的振翅反应,而密闭在透明容器中的处女雌蜂不能引发雄蜂的振翅反应.[结论]烟蚜茧蜂的交配行为由—系列固定行为组成,雌蜂传递的嗅觉线索是引发雄蜂求偶行为发生的关键因素,雌蜂腹部是短程雌性性信息素产生的来源.     

棉大卷叶野螟繁殖特性研究

在实验室温度为25±2℃、光周期为L13：D11（光照时间为06：00～19：00）的条件下,初步研究了棉大卷叶野螟的繁殖特性。结果表明,雌、雄虫的平均交配前期分别为3．96±0．16d和3．56±0．16d;雌虫的平均产卵前期为4．00±1．52d;熄灯后40min,交配发生概率逐渐升高,交配高峰发生在20：00～22：00之间;雌成虫在熄灯后约30min开始产卵,产卵高峰发生在20：00～22：00之间。     

克氏原螯虾交配行为的研究

本文以对比行为实验方法研究了克氏原螯虾的交配行为。结果表明，克氏原螯虾交配过程可分为交配前期和交配期。在交配前期．雄虾表现出特有的交配前期行为；交配期包括钳夹、翻转、横跨、交尾和分离五个阶段。雌虾被雄虾钳住后表现顺从行为；而在对照组中的雌虾被同性钳住后却不表现顺从行为。雄虾之间的接触导致进攻行为。交配时雄虾横跨的步足均为右第5步足；雌虾在交配前勿需生殖蜕皮，交配的成败与雄虾接近雌虾的行为方式有关。且螯足较大的雄性个体交配成功率明显较高。     

克氏原螯虾交配行为的研究

本文以对比行为实验方法研究了克氏原螯虾的交配行为。结果表明，克氏原螯虾交配过程可分为交配前期和交配期。在交配前期．雄虾表现出特有的交配前期行为；交配期包括钳夹、翻转、横跨、交尾和分离五个阶段。雌虾被雄虾钳住后表现顺从行为；而在对照组中的雌虾被同性钳住后却不表现顺从行为。雄虾之间的接触导致进攻行为。交配时雄虾横跨的步足均为右第5步足；雌虾在交配前勿需生殖蜕皮，交配的成败与雄虾接近雌虾的行为方式有关。且螯足较大的雄性个体交配成功率明显较高。     

沙柳木蠹蛾性行为的生物学特性

沙柳木蠹蛾(Holcocerus arenicola staudinger)是为害沙柳(Salix psammophila)根部的一种钻蛀性害虫。通过对沙柳木蠹蛾羽化行为、性比和寿命的调查,对各日龄雌蛾求偶和交尾发生时间的统计分析,明确了沙柳木蠹蛾性行为的动态节律。结果表明:沙柳木蠹蛾在19:00～21:00羽化最为集中;雌雄性比平均为0.66∶1;成虫平均寿命4.8±2.2d,其中雌蛾的寿命稍高于雄蛾。雌蛾在进入暗期1～2h内求偶行为明显,最大求偶百分率出现在羽化后的第二晚。1日龄成虫的交配高峰在暗周期的前2h,而2～4日龄成虫的交配高峰是在暗期的1h内;交配持续的平均时间为38.41±11.42min。随着蛾龄的增大,雌虫的求偶和交配行为发生的时间提前。沙柳木蠹蛾的性活动高峰出现在羽化后连续3个暗周期的前半段,可作为利用性信息素防治沙柳木蠹蛾最佳时段的参考依据。     

交配对棉铃虫雌蛾生殖的调控

研究交配对棉铃虫雌蛾生殖的影响，结果表明：（1）有效交配明显刺激卵巢发育与产卵，交配后24h，交配蛾的卵巢与体重比值较同龄处女蛾提高56．6％，交配雌蛾一生产卵量是处女雌蛾的1．8倍，差异极显。大量的卵的产出使交配后雌蛾体重锐减。死亡时只有羽化的45．2％，明显低于处女雌蛾。（2）有效交配极显抑制了雌蛾的求偶，使雌蛾求偶率降低了87．1％。（3）交配使3日龄雌蛾的性信息素在2h后下降91％。（4）已有效交配的雌蛾当晚不再交配，表现出典型的拒绝行为。（5）有效交配雌蛾寿命为10.4d，显短于无效交配的雌蛾（15．6d)。极显短于单头饲养雌蛾（18．9d).     

异色瓢虫的交配及配后的保护行为研究

通过室内试验,对异色瓢虫的交配及配后的保护行为进行了初步研究.结果表明:异色瓢虫完成交配时间为110.89 min,雌雄虫生殖器结合39 min后雄虫的身体开始晃动,完成一次交配雄虫晃动的总时间为75.11min,雄虫晃动的回合数为129.57个,每个晃动回合包括几个至十几个身体左右晃动的单元,晃动持续直至交配结束.交...     

Females' choice of "good genotypes" as mates is promoted by an insect mating system

Can animal mating systems result in the choice of mates carrying genotypes that are otherwise favored by natural selection? This question is addressed by studying, in natural populations of Colias butterflies, how the phosphoglucose isomerase (PGI) enzyme genotype of males mating Colias females varies with degree of female mate discrimination. Certain PGI genotypes (as predicted from their biochemical properties) have been found previously to have an advantage in diverse fitness-related properties: flight capacity, survivorship, and overall mating success. It is shown here that males of these same genotypes have even greater advantage in remating older, more discriminating females than they do in mating previously unmated, less discriminating females. Assortative mating is not found and thus cannot explain this effect. The mating system of these insects does, at least in this case, result in active female choice of generally favorable male genotypes as mates.     

昆虫精子竞争及其避免机制

精子竞争是指来自2个或2个以上雄性个体的精子为争夺对卵的授精权而展开的竞争。精子竞争是雄性相互竞争的最终形式,是行为生态学与进化生物学的热点。阐述了精子竞争的概念,综述了精子层化、精子失能、精子移除和精子冲洗4种昆虫精子竞争的机制以及雄性在形态、生理和行为上3类避免精子竞争的机制,详细讨论了交配次序、交配雄性数量、交配间隔以及隐秘雌性选择4个影响父权偏向的因素。笔者认为围绕精子竞争研究应尽快开展如下工作:开展精液成分的鉴定以及对精子竞争的影响作用研究,开展精子的形态、行为、生理和功能的研究,以及开展精子、雌性生殖道与卵的交互作用关系、父权偏向的精确机制等研究。     

普通大蓟马子代性比对同种成虫气味的响应

为了探究同种成虫的气味对普通大蓟马(Megalurothrips usitatus)交配期间性比调节的影响,设置对照（无气味）、已交配雌虫、未交配雌虫和已交配雄虫等4种气味源,分别处理单对刚羽化成虫24 h,然后用幼嫩豇豆(Vigna unguiculata)豆荚单头饲养被测雌虫,观测每日所产子代的性别和数量,计算子代性比。结果表明：已交配雌虫气味处理的子代雌虫数（22.80头）最少,跟其他处理差异显著。同对照的子代性比（0.31）相比,已交配雌虫和未交配雌虫的气味分别导致子代性比显著提高和降低,子代性比分别为0.48和0.22,而已交配雄虫气味对子代性比无显著影响。4个处理中,仅已交配雌虫气味处理的雌虫在产卵最后1天的日性比达到1.00,即雌虫体内的精子已消耗殆尽。成虫气味源对雌虫产卵天数没有明显影响。实验结果说明,普通大蓟马在交配期间能依靠嗅觉判别周边雌虫的交配状况,然后通过调控雌虫的获精数量,实现对子代性比的自调节。     

Sexual selection can resolve sex-linked sexual antagonism

Sexual selection is a potent evolutionary force. However, very few models have considered the evolution of female preferences for traits expressed in both sexes. Here we explore how female preferences coevolve with sexually antagonistic traits, which involve alleles that are beneficial to one sex but harmful to the other. We show that with a sexually antagonistic trait on the X chromosome (males XY, females XX), females evolve to prefer mates carrying alleles beneficial to daughters. In contrast, with a Z-linked trait (males ZZ, females ZW), females more often evolve mating preferences for mates carrying alleles beneficial to sons (that is, flashy displays).     

卵巢打点注射质粒pIRES2-EGFP生产转基因兔的研究

本研究以绿色荧光蛋白为报告基因,转染兔卵母细胞,探索建立操作方便、效率高、成本低、可定量生产转基因兔的可行性方法.选择14只成年新西兰雌兔,每侧卵巢内分别打点注射0.25 mL 0.5～0.8 mg/mL的质粒,注射后第3日、第16日和第31日进行人工辅助配种;卵巢注射后第3日、第16日和31日随机各取1只雌兔卵巢做冰冻切片,置荧光显微镜下观察绿色荧光;应用PCR 和 Southern 杂交检测转基因新生仔兔阳性率.结果经荧光显微镜观察,卵巢注射后第3日配种的雌兔卵巢冰冻切片及48 h以后的胚胎呈现绿色荧光;卵巢注射报告基因后第3日配种的雌兔后代阳性率最高,PCR 和 Southern 杂交检测结果分别为72.7 %和45.5 %;第31日配种的后代阳性率最低,分别为36.8 %和15.8 %;第16日配种、第3日配种和第31日配种雌兔的阳性后代数量呈递减趋势.卵巢注射后第3日配种,虽然后代阳性率较高,但是其产仔数最少.实验结果表明,用注射器直接对卵巢打点注射外源基因生产转基因兔的方法操作简便、高效,为日后大规模制备一些大型家畜的转基因后代奠定了基础.     

马铃薯块茎蛾交配行为研究

研究了马铃薯块茎蛾成虫的交配行为,结果表明,成虫羽化当天即可进行交配,交配高峰出现在黑暗后1．0～3．0h,交配活动以羽化后2—4d表现强烈,以4日龄雌虫和3日龄雄成虫的组合效果最佳。雌雄蛾有多次交配习性,雄蛾平均交配3．2次,雌蛾有二次求偶现象。补充营养影响雌蛾起始求偶时间。     

亚洲型舞毒蛾的羽化和生殖行为节律

为了探究亚洲型舞毒蛾(Lymantria dispar asiatica)的羽化和生殖昼夜节律,在自然光周期和温湿度条件下对亚洲型舞毒蛾成虫的羽化、求偶、交配及产卵行为进行了观察,并利用触角电位反应测定了处女雌蛾性信息素的合成量与日龄之间的关系。结果表明:亚洲型舞毒蛾雌蛾在化蛹后11 d,雄蛾在化蛹后12 d分别出现羽化高峰;雌雄蛾的羽化行为均发生在光期前2 h(02:00)至暗期3 h(21:00),雄蛾羽化高峰期为光期6 h(09:00),较雌蛾(11:00)提前2 h。雌蛾羽化约2 h后开始求偶,1日龄雌蛾的求偶率随时间的推移逐渐上升,而其他日龄的雌蛾仅在光周期开始后的1 h内求偶率降至当日最低(75%),其余时间达到或接近100%;2日龄雌蛾体内的性信息素合成量最高,以后逐日下降。成虫羽化当日即可交尾,室内交尾高峰期发生在光期11 h(14:00)左右,次高峰出现在暗期6 h(00:00)。产卵高峰期发生在光期3 h(06:00)左右,次高峰出现在暗期2 h(20:00)。综上可见,亚洲型舞毒蛾成虫的羽化和生殖行为存在明显的昼夜节律。