动物的婚配制度

婚配制度是动物种群个体为获得配偶普遍采取的一种行为策略。一般分为单配制、一雄多雌制、一雌多雄制和混交制。作为动物的一种进化稳定对策,婚配制度又具有一定的可塑性,有时可以逆转,有时又是兼性的。配偶外交配主要存在于单配制物种中特别是单配制鸟类中。其发现表明通过观察个体间联系来确定的“社会性婚配制度”和通过个体实际上的交配对象来描述的“遗传性婚配制度”有可能存在差异。婚配制度影响有害动物的不育控制,在存在繁殖性竞争的情况下,对单配制和一雄多雌制而言,不育效果最佳。     

雌性根田鼠的亲属识别与配偶选择

在Y字型选择箱中进行3种不同熟悉处理的配偶选择实验以检验动情雌性根田鼠配偶选择时的亲属识别和近交回避。（1）动情雌鼠在熟悉雄性同胞和陌生非同胞之间嗅添频次和时间、及自我修饰时间的差异非常显著（P＜0.01),所作的脊柱前凸反应时间也有显著差异（P＜0.05),这些行为均多针对于陌生非同胞雄性。结果提示动情雌性根田鼠在熟知雄性同胞身份的条件下对陌生非亲属雄性的气味更感兴趣,在择偶中与非亲属雄性交配来实现近交回避。（2）动情雌鼠对陌生雄性非同胞的嗅添频次和时间及所作的脊柱前凸反应时间显著大于陌生同胞雄性（P＜0.05),而针对陌生雄性非同胞自我修饰时间非常显著地大于针对陌生雄性同胞（P＜0.01)。这说明动情雌性根田鼠在择偶时可以识别断奶后分离不熟悉的雄性亲属,而在交配行为上偏向于非亲属雄性。（3）动情雌鼠在熟悉雄性同胞和非同胞之间跃添时间差异明显（P＜0.05),嗅添频次的差异更甚（P＜0.01);所作的脊柱前凸反应时间和社交后自我修饰时间差异也非常显著（P＜0.01),这些行为也均都偏向于非同胞雄性;结果提示断奶后继续熟悉可维持动情雌鼠对雄性亲属的嗅觉识别记忆力,在交配行为上主动回避亲属雄性。故认为：断奶后嗅觉识别持久力是发情雌性根田鼠亲属识别的机制,亲属识别是最初发情的雌性根田鼠配偶选择中近交回避的首要途径和机制,熟悉性是维持雌性根田鼠配偶选择实现近交回避的机制和特征。     

东方蜜蜂入侵群体的建立机制

蜜蜂、胡蜂及蚂蚁等是具有高度入侵性的社会性昆虫.理论上,在奠基者群体数量较少时,其单一位点互补性性别决定机制会限制入侵群体的发展.在人类活动影响下,东方蜜蜂已扩散至其自然分布区之外的很多地区,给当地饲养的西方蜜蜂带来很大影响.本文简要介绍了东方蜜蜂的分布、性别决定机制以及近几年来针对澳大利亚东方蜜蜂入侵群体的系列研究结果,从蜂王的交尾行为、工蜂的繁殖行为、平衡选择作用、产雌孤雌生殖等方面分析了东方蜜蜂群体如何在奠基者效应带来的遗传负荷压力下快速发展起来,为揭示相关社会性昆虫入侵群体的建立机制提供了很好的借鉴.     

雌性选择与雄鸟鸣唱的进化

鸣唱是许多鸟类的重要的雄性第二性征之一。雄性鸣唱包含着丰富的信息：物种、领域质量、遗传状态和生理状态。这些信息可被雌性用来判断潜在配偶的素质,而雌性对复杂鸣唱的偏爱反过塑造了鸟类的鸣唱。一般认为雌性选择的调控基因位于决定性别的W染色体上。     

熟悉性对棕色田鼠和根田鼠择偶行为的影响

以两性配对共居至交配或生仔作不同熟悉处理,在Y字型选择箱中分别观察棕色田鼠,根田鼠的择偶行为和配偶识别。结果如下：（1）棕色田鼠雌雄两性均表现出对熟悉异性或配偶的喜好倾向;（2）在根 中,只有雌性表现出对熟悉雄鼠或配偶的选择倾向,雄鼠无明显的选择取向;（3）每种雌性田鼠对2种熟悉性不同的同种雄性的嗅舔时间均有显著差异性,而每种雄性田鼠对2种熟悉性不同的同种雌性的嗅舔时间均无显著差异性。这些结果表明：（1）熟悉性对棕色田鼠择偶行为的影响大于对根田鼠的影响;（2）嗅舔时间差别可反映不同田鼠的配偶识别能力,熟悉性对棕色田鼠配偶识别能力的影响大于对根田鼠的影响;（3）2种田鼠配偶识别的性别差异的一致性,提示这2种田鼠的雌性配偶识别能力均强于雄性田鼠,而雌鼠的配偶识别能力可能取决于雌鼠受酱或分娩刺激的生理状态;（4）棕色田鼠室内所表现的择偶行为的两性熟悉性特征与其单配制有关,根田鼠所表现的择偶行为的雌性熟悉性特征与其一雄多雌制有关。     

秦岭金丝猴的繁殖生物学

通过长期观察并综合有关文献,介绍了秦岭金丝猴（Rhinopithecus roxellana）的婚配制度、性成熟、交配期及交配行为、怀孕和产仔、幼仔的抚育和生长等情况,为了解金丝猴繁殖生物学特点提供参考资料。     

基于睾丸尺寸比较研究中缅树鼩的婚配制度

哺乳动物婚配制度的研究是行为生态学中具有重要意义的领域之一。研究表明,中缅树鼩Tupaia belangeri的婚配制度主要有一雄一雌制和一雄多雌制2种。为了揭示野外环境下中缅树鼩的婚配制度,本文在繁殖季节测定了雄性中缅树鼩的睾丸质量和体质量,再结合一雄一雌制、一雄多雌制和一雌多雄制的60个灵长类物种进行睾丸质量和体质量的比较分析。结果表明:研究对象的睾丸质量均随体质量增加而增大(r=0.31,P<0.05),睾丸质量和体质量在3种婚配类型之间的差异有统计学意义(睾丸质量:F=11.36,P<0.01;体质量:F=4.09,P<0.05)。不同婚配制度的物种的睾丸尺寸存在差异,中缅树鼩可能属于一雄一雌制婚配动物。研究结果还暗示,哺乳动物的睾丸尺寸可以作为预测其婚配制度的一个"可靠因子"。     

雌性延迟发育的蚜虫的性别分配

某些物种的蚜虫中,雌性个体成熟较晚,可以认为是雄性个体的“侄女”。当冬季即将来临,剩余时间就不能满足发育需求时,发育延迟了,发育延迟应当也终止了雌性功能上的投资。然而,最近的证明表明,雌性功能的投资并不停止。这种未预料到的发现可能归因于一种进化限制因素,归因于雄性个体在不同年龄阶段对配偶的竞争,或归因于不能预测导致随机非遗传多型性的最后期限。本文讨论了这三种可能性,最后一种可能性由于暂时性地解释了雌性功能中的连续投资而是一种可取的解释。尽管延缓发育和开始繁殖的最后期限常见于那些生活在严寒地区的、雌性发育迟缓的蚜虫,本文的观点也适合于一个性别成熟较晚的、具有繁殖最后期限的任何一个蚜虫物种。     

黔金丝猴食性及社会结构的初步研究

黔金丝猴(Rhinopithecus brelichi)是我国一级重点保护动物,仅分布于贵州梵净山狭小范围内(杨业勤,2002),被IUCN列为"濒危种"(IUCN, 2007).它自1903年由Thomas命名后,直到1965年才出现一些生态方面的报道(彭鸿绶等,1965),20世纪80年代,Tan(1985)、马世来等(1988)零星报道了一些黔金丝猴生态学方面的工作.     

秦岭川金丝猴一周岁内个体的行为发育

2003年3月至2004年5月在陕西周至国家自然保护区的玉皇庙地区,采用目标动物取样法(Focal ani-mal sampling)对2003年出生的5只金丝猴个体行为发育进行了观察,应用全事件记录法(All-occurrences record-ing)进行数据的收集。结果表明23日龄婴儿首次从母亲怀内爬出在树枝上活动,68日龄开始在树上攀爬跳跃,5月龄主动采食树叶和啃投食区食物,6月龄跟随社群迁移。依据婴幼儿主要行为首次出现时间及其变化,把1周岁内个体发育分为5个时期,即完全依赖期、探索外部世界期、融入社群期、适应生存期和逐步独立期。1周岁内婴幼儿活动和休息的地方是母亲怀里、其它个体怀里、树枝上和地面上。随着发育,婴幼儿在这些地方停留的时间也在变化。1周岁内婴幼儿在母亲怀中的时间与年龄存在明显的负相关,在其它个体怀里的时间与年龄也呈显著负相关。虽然独自在树上的时间与年龄相关性不显著,但在地面上停留的时间与年龄呈正相关。     

A TEST OF THE CRITICAL ASSUMPTION OF THE SENSORY BIAS MODEL FOR THE EVOLUTION OF FEMALE MATING PREFERENCE USING NEURAL NETWORKS

The sensory bias model for the evolution of mating preferences states that mating preferences evolve as correlated responses to selection on nonmating behaviors sharing a common sensory system. The critical assumption is that pleiotropy creates genetic correlations that affect the response to selection. I simulated selection on populations of neural networks to test this. First, I selected for various combinations of foraging and mating preferences. Sensory bias predicts that populations with preferences for like-colored objects (red food and red mates) should evolve more readily than preferences for differently colored objects (red food and blue mates). Here, I found no evidence for sensory bias. The responses to selection on foraging and mating preferences were independent of one another. Second, I selected on foraging preferences alone and asked whether there were correlated responses for increased mating preferences for like-colored mates. Here, I found modest evidence for sensory bias. Selection for a particular foraging preference resulted in increased mating preference for similarly colored mates. However, the correlated responses were small and inconsistent. Selection on foraging preferences alone may affect initial levels of mating preferences, but these correlations did not constrain the joint evolution of foraging and mating preferences in these simulations.     

THE IMPORTANCE OF FEMALE CHOICE,MALE–MALE COMPETITION,AND SIGNAL TRANSMISSION AS CAUSES OF SELECTION ON MALE MATING SIGNALS

Selection on advertisement signals arises from interacting sources including female choice, male–male competition, and the communication channel (i.e., the signaling environment). To identify the contribution of individual sources of selection, we used previously quantified relationships between signal traits and each putative source to predict relationships between signal variation and fitness in Enchenopa binotata treehoppers (Hemiptera: Membracidae). We then measured phenotypic selection on signals and compared predicted and realized relationships between signal traits and mating success. We recorded male signals, then measured lifetime mating success at two population densities in a realistic environment in which sources of selection could interact. We identified which sources best predicted the relationship between signal variation and mating success using a multiple regression approach. All signal traits were under selection in at least one of the two breeding seasons measured, and in some cases selection was variable between years. Female preference was the strongest source of selection shaping male signals. The E. binotata species complex is a model of ecological speciation initiated by host shifts. Signal and preference divergence contribute to behavioral isolation within the complex, and the finding that female mate preferences drive signal evolution suggests that speciation in this group results from both ecological divergence and sexual selection.     

GOOD GENES AND DIRECT SELECTION IN THE EVOLUTION OF MATING PREFERENCES

A model is used to study quantitatively the impact of a good genes process and direct natural selection on the evolution of a mating preference. The expression of a male display trait is proportional to genetic quality, which is determined by the number of deleterious mutations a male carries throughout his genome. Genetic variances and covariances, including the covariance between the preference and male trait that drives the good genes process, are allowed to evolve under an infinitesimal model. Results suggest that the good genes process generates only weak indirect selection on preferences, with an effective selection intensity of a few percent or less. If preferences are subject to direct natural selection of the intensity observed for other characters, the good genes process alone is not expected to exaggerate the male trait by more than a few phenotypic standard deviations, contrary to what is observed in highly sexually selected species. Good genes can, however, cause substantial exaggeration if preference genes are nearly selectively neutral. Alternatively, direct selection on preference genes, acting on mating behavior itself or on the genes' pleiotropic effects, can cause mating preferences and male display traits to be exaggerated by any degree. Direct selection of preference genes may therefore play an important role in species that show extreme sexual selection.     

ORIGIN AND MAINTENANCE OF A FEMALE MATING PREFERENCE

We investigated the role of maintenance and origin of female mating preferences in three species of fish. Poecilia latipinna and P. mexicana are sexual species that hybridized to form the gynogenetic clonal P. formosa, which reproduces asexually but requires sperm to initiate embryogenesis. We demonstrate that all three species display almost identical and statistically indistinguishable preferences for large males. Although processes of good genes, runaway sexual selection, and direct selection could maintain preferences in the sexual species, good genes and runaway sexual selection are unlikely to operate in the asexual species. Furthermore, we found that the most likely direct selection benefit, an increase in fecundity, can also be excluded in the gynogens. We conclude that the most parsimonious explanation for this P. formosa preference is that it was inherited from the parental species and is maintained without forces generated by good genes, runaway selection, or direct selection for increased fecundity. This preference may be maintained because of pleiotropic effects (e.g., sensory bias) or mate searching costs.     

EVOLUTION OF MULTIPLE KINDS OF FEMALE SPERM-STORAGE ORGANS IN DROSOPHILA

Females of all species belonging to the family Drosophilidae have two kinds of sperm-storage organs: paired spherical spermathecae and a single elongate tubular seminal receptacle. We examined 113 species belonging to the genus Drosophila and closely allied genera and describe variation in female sperm-storage organ use and morphology. The macroevolutionary pattern of organ dysfunction and morphological divergence suggests that ancestrally both kinds of organs stored sperm. Loss of use of the spermathecae has evolved at least 13 times; evolutionary regain of spermathecal function has rarely if ever occurred. Loss of use of the seminal receptacle has likely occurred only once; in this case, all descendant species possess unusually elaborate spermathecae. Data further indicate that the seminal receptacle is the primary sperm-storage organ in Drosophila. This organ exhibits a pattern of strong correlated evolution with the length of sperm. The evolution of multiple kinds of female sperm-storage organs and the rapidly divergent and correlated evolution of sperm and female reproductive tract morphology are discussed.     

GENETIC CONSTRAINTS ON THE INDEPENDENT EVOLUTION OF MALE AND FEMALE REPRODUCTIVE CHARACTERS IN THE TRISTYLOUS PLANT LYTHRUM SALICARIA

Here we test whether the potential exists for the independent evolution of allocation to male, female, and attractive functions within a flower. We employed half-sib and parent-offspring regression methods in the tristylous plant Lythrum salicaria to determine whether there is additive genetic variation for characters important to male and female reproductive success and whether genetic correlations could constrain the independent evolution of male and female function. Although significance levels were not consistent among morph types or between populations, there were significant narrow-sense heritabilities for several traits including stamen mass, pistil mass, perianth mass, petal length, and calyx length. Traits that might be under strong stabilizing selection to promote specific pollen transfer, such as stamen and style lengths, had little heritable variation. In the majority of cases in which heritable variation was present, there were positive genetic correlations among floral traits. A strong positive genetic correlation appeared between stamen and pistil mass in the short-styled morph from one of the populations studied. This suggests that selection might not be able to act independently on biomass allocation to male and female flower parts. No evidence of negative genetic correlations appeared that would suggest trade-offs and that could augment a selection response towards sexual specialization. The observed positive correlations could be explained if we consider the “functional architecture” that underlies the covariance structure. If there is more covariance generated by pleiotropic loci controlling overall flower size than at loci controlling male versus female allocation, it could result in the observed positive covariance. At the phenotypic level, we did find significant negative partial correlations between male and female traits when flower size was controlled, but these trade-offs were among rather than within morphs.     

MULTIPLE GENETIC MECHANISMS FOR THE EVOLUTION OF SENESCENCE IN DROSOPHILA MELANOGASTER

We present the results of selection experiments designed to distinguish between antagonistic pleiotropy and mutation accumulation, two mechanisms for the evolution of senescence. Reverse selection for early-life fitness was applied to laboratory populations of Drosophila melanogaster that had been previously selected for late-life fitness. These populations also exhibited reduced early-age female fecundity and increased resistance to the stresses of starvation, desiccation, and ethanol, when compared to control populations. Reverse selection was carried out at both uncontrolled, higher larval rearing density and at controlled, lower larval density. In the uncontrolled-density selection lines, early-age female fecundity increased to control-population levels in response to the reintroduction of selection for early-age fitness. Concomitantly, resistance to starvation declined in agreement with previous observations of a negative genetic correlation between these two characters and in accordance with the antagonistic-pleiotropy mechanism. However, resistance to stresses of desiccation and ethanol did not decline in the uncontrolled-density lines during 22 generations of reverse selection for early-life fitness. The latter results provide evidence that mutation accumulation has also played a role in the evolution of senescence in this set of Drosophila populations. No significant response in early-age fecundity or starvation resistance was observed in the controlled-density reverse-selection lines, supporting previous observations that selection on Drosophila life-history characters is critically sensitive to larval rearing density.     

MALE MATE CHOICE AND THE EVOLUTION OF FEMALE PLUMAGE COLORATION IN THE HOUSE FINCH

The house finch (Carpodacus mexicanus) is a sexually dichromatic passerine in which males display colorful plumage and females are generally drab brown. Some females, however, have a subdued version of the same pattern of ornamental coloration seen in males. In previous research, I found that female house finches use male coloration as an important criterion when choosing mates and that the plumage brightness of males is a reliable indicator of male nest attentiveness. Male house finches invest substantially in the care of young and, like females, stand to gain by choosing high-quality mates. I therefore hypothesized that a female's plumage brightness might be correlated with her quality and be the basis for male mate choice. In laboratory mate choice experiments, male house finches showed a significant preference for the most brightly plumaged females presented. Observations of a wild population of house finches, however, suggest that female age is the primary criterion in male choice and that female plumage coloration is a secondary criterion. In addition, yearling females tended to have more brightly colored plumage than older females, and there was no relationship between female plumage coloration and overwinter survival, reproductive success, or condition. These observations fail to support the idea that female plumage coloration is an indicator of individual quality. Male mate choice for brightly plumaged females may have evolved as a correlated response to selection on females to choose brightly colored males.