Assortative Mating

Abstract

Theories of mate selection and the effects of assortative mating are reviewed, including differences in the basic theoretical orientations of the social and biological sciences with respect to human evolution and assortative mating. Topics discussed include evolution in parallel and interaction, terminology of nonrandom mate selection, theories of mate choice, social stratification and class endogamy, and suggestions for future research.     

Female Fitness Optimum at Intermediate Mating Rates under Traumatic Mating

Traumatic mating behaviors often bear signatures of sexual conflict and are then typically considered a male strategy to circumvent female choice mechanisms. In an extravagant mating ritual, the hermaphroditic sea slug Siphopteron quadrispinosum pierces the integument of their mating partners with a syringe-like penile stylet that injects prostate fluids. Traumatic injection is followed by the insertion of a spiny penis into the partner's gonopore to transfer sperm. Despite traumatic mating, field mating rates exceed those required for female fertilization insurance, possibly because costs imposed on females are balanced by direct or indirect benefits of multiple sperm receipt. To test this idea, we exposed animals to a relevant range of mating opportunity regimes and assessed the effects on mating behavior and proxies of female fitness. We find penis intromission duration to decrease with mating rates, and a female fecundity maximum at intermediate mating rates. The latter finding indicates that benefits beyond fertilization insurance can make higher mating rates also beneficial from a female perspective in this traumatically mating species.     

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。     

Mating Type Interaction in Closterium peracerosum-strigosum-littorale: Mating Induced Protoplast Release

Mating type interaction between heterothallic strains of Closteriumperacerosum-strigosum- littorale was studied during the conjugationprocess. When vegetative cells of opposite mating types weremixed under the nitrogen depleted mating conditions, the formationof conjugation-papilla and the release of the protoplast withinthe distended papilla from the gametangial cell were shown inboth the paired and unpaired cells. The protoplasts of pairedcells fused to form zygotes, while those of unpaired cells broke.When cells were mixed at a ratio of around 5 to 3 (mating typeplus to mating type minus), sexual activation occurred at thehighest frequency. Mixing at a ratio of 1 to 3, however, inducedthe highest frequency of disrupted cells. Mating type plus cellswere found to be broken specifically when direct contact withmating type minus cells was prevented. This disruption seemedto be mediated by a factor secreted from mating type minus cells. (Received March 20, 1981; Accepted August 18, 1981)     

The Syngens of Paramecium bursaria: New Mating Types and Intersyngenic Mating Reactions

SYNOPSIS. Three syngens of Paramecium bursaria have been identified amongst stocks collected in Scotland. These syngens probably correspond to the previously-described syngens 4, 5 and 6; they have been so named. In all 3 syngens 8 mating types have been found. An extensive series of intersyngenic mating reactions has been discovered between stocks of syngens 4 and 5, and between stocks of syngen 2 and syngens 4 and 5.     

Mating system of Microcebus murinus

Microcebus murinus, a small nocturnal lemur from Madagascar, has retained features of ancient primates. Based on these ancestral traits, its social organization has often been used as a model for early primate social systems. In captivity it breeds polygynously, i.e., one male mates with several females, while females usually copulate only with the dominant male. The present project tested whether or not sexual size dimorphism, spatial distribution, and relative testis size of M. murinus correspond with predictions of the sexual selection theory concerning polygynous mating systems. The study was combined with a mark‐recapture study and radio tracking of 12 animals in 1993 in a dry deciduous forest of western Madagascar at the end of the dry season. Large overlapping home ranges in males, lack of sexual size dimorphism, and relatively large testes suggest a multi‐male mating system, i.e., one that is promiscuous rather than polygynous. Am. J. Primatol. 48:127–133, 1999. © 1999 Wiley‐Liss, Inc.     

Courtship Disruptions and Male Mating Strategies: Examples from Female-Defense Mating Systems

Males frequently interrupt the copulation attempts of other males, and these courtship disruptions may limit the extent to which a few males are able to monopolize mating access to females. Males actively defend sexually receptive females in many species in which females form dense aggregations during the breeding season. Across and within such species there is considerable variation in the mating tactics adopted by males, with males in some cases defending groups of females and in other cases sequentially consorting with individual females. Colonial blackbirds have been central to studying this mating system, and we develop a conceptual model for how courtship disruption may account for variation in male mating tactics in this group. Our model assumes that the frequency of disruptions increases with greater colony size. As a consequence, successful copulations are less likely to occur at large colonies than at small colonies, and males are expected to switch from defending multiple females at the colony to consorting individual females away from it. Results from two species of blackbird support the basic assumptions of this model. In one species, the Montezuma oropendola, disruptions occur rarely and males defend groups of females, whereas in the other species, the yellow-rumped cacique, disruptions are frequent and males defend single females. Moreover, consistent with a key prediction, within each species, males associated with small colonies remain at the colony and defend groups of females, whereas males spend little time defending groups of females at large colonies and rarely attempt copulations there. This model has the potential to explain variation in male mating strategies and female monopolization for other taxa in which females form breeding aggregations.     

Mating behaviour of Ctenomyces serratus

Nineteen isolates of Ctenomyces serratus including three pairs of tester strains were crossed in all possible combinations on diluted Pablum cereal agar with added salts, oatmeal salts agar-Medium E, and soil and hair medium. Out of 190 crosses, 18 were fertile and the remaining 172 were sterile. Of the 19 isolates, seven were– mating type, 11 were + mating type, and one (UAMH 1959) was non-fertile with the other isolates. The high degree of non-fertile crosses among the 19 isolates shows that the use of mating reactions for the identification of conidial isolates of C. serratus may not be a practical tool. unless a large number of isolates belonging to both the mating types are employed. The production of exudate droplets in the fertile crosses seemed to be correlated with the degree of mating response. Ascocarp morphology corresponded closely to that of a cleistothecium, because of the completely closed nature. Ascospores were quite alike in their size, but they differed in shape, depending on their orientation.     

Mating Patterns of Plasmodium falciparum

Recent empirical data have enabled a more informed debate over the extent of clonality in Plasmodium falciparum populations. Oocyst heterozygosity data reveal that the mating structure of malaria populations varies according to the transmission intensity. This finding provides a more detailed picture of the malaria mating structure than previous conclusions, which were based on indirect measures of population mating structure, ie. linkage disequilibrium analyses. In this article, Ric Paul and Karen Day discuss aspects of the genetic structure of malaria populations as evidenced by oocyst heterozygosity and linkage disequilibrium data. They address the difficulties of performing genetic analyses of malaria parasite population structure inherent in parasite sampling, why two identical parasites are rarely observed in the field and how features of the epidemiology determine parasite population structure.     

衣藻有性生殖的分子机制

衣藻作为分子生物学研究的模式材料,被广泛用于植物光合作用、鞭毛组装与功能、细胞周期与节律、细胞信号传导与光感受、细胞识别等重要生物学过程的研究,而且衣藻有性生殖的分子机制与人类某些疾病的发生机制存在联系.该文对国内外近年来有关莱茵衣藻在有性生殖过程中凝集素的动态分布,包括鞭毛粘连、补充、传递、脱粘连、凝集素合成的正调节,以及与性凝集素行为有关的基因研究进展进行综述,以阐明衣藻有性生殖的分子机制,为人类的疾病研究提供参考.     

大猿叶虫交配行为的观察

大猿叶虫Colaphellus bowringi Baly是十字花科上的重要害虫,一生能多次交配。本试验在25℃,光周期L∶D=12∶12条件下观察了大猿叶虫成虫连续7d的交配行为。结果表明:(1)每日平均交配(5.67±0.26)次,最高可达11次,不同日龄间的交配次数存在显著差异。(2)平均每日用于交配的时间为(238±10)min,占总时间的33.5%,最长可达493min,占总时间的68.5%,不同日龄间的交配时间有极显著差异。(3)交配持续时间最短8min,最长达289min,平均为(48±2)min;同一日内,随着交配次数增加,交配持续时间逐渐缩短;不同日龄间的交配持续时间存在显著差异。(4)相邻两次交配之间的间隔时间最短5min,最长300min,平均交配间隔(75±3)min;交配间隔时间随日龄的增加而明显延长。     

Mating types inPichia membranaefaciens

Mating types have been found in a strain ofPichia membranaefaciens. The implication of this finding for the classification of some heterothallic species provisionally placed in the genusEndomycopsis is considered.