Genetics of the polycross

Summary Seeds from polycrosses with Norway spruce, in which the same sixteen male parents were crossed to a number of female parents in each of two years, were analysed electrophoretically to detect departures from male gamete frequencies expected assuming equal male fertilities, and to detect heterogeneity among female parents in male gamete frequencies in seeds. The data were also used to estimate the fertilities of the polycross trees used as male parents. Significant departures from male gamete frequencies expected assuming equal male fertilities were found in the seed pooled from all crosses. Male fertilities estimated from male gamete frequencies in seed from all crosses also departed significantly from expectation. The results are discussed with respect to assumptions made when estimating general combining abilities and expected response to selection in polycrosses.     

布氏田鼠雄性的优势地位

在实验条件下对雄性成年布氏田鼠（Microtus brandti）相遇后的优势地位及生理指标的研究结果表明：布氏田鼠雄性之间存在严格的等级关系;优势雄鼠生理指标中睾丸重量和血清睾酮激素含量高于从属雄鼠,而血清中皮质醇激素的含量低于从属雄鼠。优势雄鼠的探究、攻击和修饰等行为频次显著高于从属雄鼠,而从属雄鼠在跳跃频次上多于优势雄鼠。随着观察时间的延长,不论优势个体还是从属个体,其探究频次都呈现明显的下降趋势,其他行为的频次则没有显著差异。相关性检验说明,除攻击行为可以作为判断区分雄鼠等级的依据之外,修饰行为也可以作为判断的依据。     

紫稻细胞质雄性不育系叶片全蛋白双向电泳分析

通过对几种不育系叶片全蛋白双向电泳图谱分析证明;紫稻不育系具有不同于野败型,红莲型和马协型不育系的蛋白图谱,说明其可能是一种新的细胞质质源,同时,紫稻不育系与保持系蛋白图谱之间在三叶期和分蘖期时差异均不明显,但各材料本身蛋白图谱在两个不同时期之间差异很大,不育系与保持系图谱表现出的蛋白质（多肽）的差异,可能与不育系雄性不育有关。     

桔梗雄性不育花药的发育解剖学研究

通过田间观察和石蜡切片法对桔梗不育和可育花药的形态及其解剖结构进行了比较研究,结果表明:桔梗可育和不育花器形态、花药长度无明显差异,而开花后,可育花药饱满、有光泽、有花粉粒散出,不育花药皱瘪、无光泽、无花粉粒散出;不育花药绒毡层提前退化解体,导致小孢子发育异常。     

Female preference of the gobiid fish Eviota abax in relation to elongation of the first dorsal spine in males

The significance of elongation of the first and second spines of the first dorsal fin in male Eviota abax (Gobiidae) was examined in relation to female preference. Reproductive behavior occurred in three phases: male approach to female home, male leading female to nest, and male entering nest. During each phase, the female either accompanied the male or departed. The ratio of positive female mating responses to males before the elongated male dorsal spines were clipped and thereafter was compared in an aquarium. Females preferred male elongated spines in the first phase of courtship, but not in the second phase . Because females may be more exposed to predators during the second phase, owing to conspicuous male courtship, their greater receptivity to elongated dorsal spines in the first phase may decrease predation pressures during subsequent phases of courtship. Electronic Publication     

Microanatomy and Development of the Dwarf Male of Symbion pandora (Phylum Cycliophora): New Insights from Ultrastructural Investigation Based on Serial Section Electron Microscopy

Cycliophorans have a complex life cycle that involves several sexual and asexual stages. One of the sexual stages is the 40 μm-long dwarf male, which is among the smallest free-living metazoans. Although the dwarf male has a highly complex body plan, this minute organism is composed of a very low number of somatic cells (~50). The developmental processes that give rise to this unique phenotype are largely unknown. Here we use high resolution serial block face—scanning electron microscopy to analyze the anatomy and morphogenesis of three cycliophoran dwarf males at different developmental stages ranging from internal bud to mature male. The anatomical and morphological features of the mature dwarf male stage reported here largely correspond to those reported in earlier studies. Interestingly, the organs that typically characterize the anatomy of the mature dwarf male, e.g., muscles, brain, testis and glands, are already formed in the young male. However, there are striking differences between the mature male and young male stages at the level of cellular architecture. Thus, while the young male stage, like the internal bud stage, possesses approximately 200 nucleated cells, the mature male stage comprises only around 50 nucleated cells; muscle and epidermal cells of the mature male lack nuclei. Moreover, the total body volume of the mature male is only 63% of the body of the young male implying that the maturation of the young male into a mature male involves a marked reduction of internal body volume, mainly by massive nuclei loss. Our comparative analysis of these dwarf male specimens reveals unprecedented insight into the striking morphological and developmental differences that characterize these highly miniaturized male stages both at the level of body organization and at the level of cellular ultrastructure.     

Effects of male age on the mating behavior of both sexes in the sorghum plant bug, Stenotus rubrovittatus (Hemiptera: Miridae)

In the sorghum plant bug Stenotus rubrovittatus (Matsumura) (Hemiptera: Miridae), mating behavior consists of male courtship and female mating receptivity. Previous studies have found that female age is correlated with ovary development and that mature females with developed ovaries are more receptive to male courtship. Thus, we examined whether male age affects the mating behavior of both sexes and male accessory gland development. Unmated males 0–9 days after emergence and 3-day-old virgin females receptive to male courtship were studied. Immediately after emergence, only 20 % of the males courted females (n = 25). At 3 days old, 68 % of the males courted females (n = 25), the most active age. In contrast, more than 75 % of the courted females were receptive to the male courtship regardless of male age. These results indicate that only male courtship behavior is affected by male age, although it is not enhanced in proportion to male age. Male accessory glands developed with male age. However, no clear relationship was detected between male courtship behavior and accessory gland development. In S. rubrovittatus, it is difficult to explain male courtship behavior solely from male age and accessory gland development.     

Interacting effects of predation risk and male and female density on male/female conflicts and mating dynamics of stream water striders

We used a factorial experiment to examine interacting effectsof male density, female density, and sunfish (predation risk)on mating dynamics of the stream water strider (Aquarius remigis).Many of our results corroborated earlier studies on the isolatedeffects of each factor on mating behavior. The effect of eachfactor, however, depended on the other factors. For example,in low density pools, predation risk decreased male generalactivity, male/female harassment rates, mating activity, andmating duration and increased the large male mating advantage.At higher densities, however, water striders apparently enjoyed"safety in numbers" and did not alter their mating dynamicsin response to the presence of predators. Female activity showeda particularly complex response to male density and fish. Whenmales were scarce, fish caused females to reduce their activity.However, when males were abundant, fish increased female activity,probably because fish decreased male activity thus releasingfemales from harassment by males. The three treatment factorsalso had interacting effects on male mating success. In theabsence of fish, when females were scarce, increased male densityresulted in a decrease in mean male mating success; however,when females were abundant, increased male density enhancedmean male mating success. In contrast, in the presence of fish,male density had little effect on male mating success. Manyof the observed mating patterns can be explained by the effectsof ecological and social factors on male/female conflicts; thatis, on male harassment of females and female reluctance to mate.     

Reproductive success of two male morphs in a free-ranging population of Bornean orangutans

The reproductive success of male primates is not always associated with dominance status. For example, even though male orangutans exhibit intra-sexual dimorphism and clear dominance relationships exist among males, previous studies have reported that both morphs are able to sire offspring. The present study aimed to compare the reproductive success of two male morphs, and to determine whether unflanged males sired offspring in a free-ranging population of Bornean orangutans, using 12 microsatellite loci to determine the paternity of eight infants. A single flanged male sired most of the offspring from parous females, and an unflanged male sired a firstborn. This is consistent with our observation that the dominant flanged male showed little interest in nulliparous females, whereas the unflanged males frequently mated with them. This suggests that the dominant flanged male monopolizes the fertilization of parous females and that unflanged males take advantage of any mating opportunities that arise in the absence of the flanged male, even though the conception probability of nulliparous females is relatively low.     

二化螟雄蛾交配行为与精巢大小的关系

【目的】为了明确二化螟Chilo suppressalis雄蛾交配行为与精巢大小的关系,阐明信息素群集诱杀防治二化螟的有效性。【方法】本研究通过测定和比较不同日龄、交配状态以及性信息素诱捕的二化螟雄蛾精巢体积,建立精巢体积与雄蛾发育及交配状态的相关性。【结果】雄蛾日龄显著影响二化螟的交配,刚羽化(0日龄)雄蛾的交配率较低,1日龄雄蛾的交配率最高,之后随着日龄增加交配率逐渐降低。精巢体积与二化螟雄蛾日龄之间存在显著的负相关性。同一日龄交配的二化螟雄蛾的精巢体积显著大于未交配雄蛾;性诱捕器诱捕雄蛾的精巢体积显著大于未被性诱捕器诱捕雄蛾,与已交配雄蛾的精巢体积相似。交配之后,精巢的发育过程和未交配雄蛾相似。田间性信息素引诱二化螟雄蛾精巢体积小于0-1日龄未交配雄蛾,大于2-6日龄未交配雄蛾。【结论】本研究结果表明,二化螟雄蛾对雌蛾性信息素的反应与其精巢大小存在正相关性;性信息素引诱的二化螟雄蛾具有更强的性信息素反应能力,同时性信息素引诱的大部分雄蛾为未交配状态;交配过程并不影响二化螟雄蛾精巢体积,也不影响精巢发育。二化螟交配能力与精巢大小的关系在理论上解释了性信息素群集诱杀二化螟的防控有效性,并为其他蛾类昆虫的交配研究提供依据。     

Using video playback to study the effect of an audience on male mating behavior in the Sailfin molly (Poecilia latipinna)

Sexual conflict in poeciliid fishes is well-documented, particularly male sexual harassment and its effects on females. For instance, male attempts to force copulations influence female feeding, energy allocation, and preference for shoaling partners. However, there has been little research conducted to determine how the social environment shapes the occurrence and intensity of sexual harassment. In this study we ask whether an audience male influences the sexual behaviors of a focal male, the correlated feeding time reduction of female Poecilia latipinna, and if the size of the audience male (larger or smaller than the focal male) influences these behaviors. We presented a video of a male, either smaller or larger than the focal male, or an empty tank (control) to a female interacting with a male or female partner and measured feeding times and sexual behaviors. We found that male sexual behaviors increased in the presence of an audience male, especially if the audience male was larger than the focal male. Females fed more in the presence of a partner female than in the presence of a male, which was independent of the audience (i.e., video treatment). Focal female aggression towards the partner female increased with the size of the audience male. The present study shows that an audience male has multiple interacting influences on both male and female behavior.     

植物细胞核雄性不育的分子基础

植物细胞核雄性育性相关基因克隆,使我们对细胞核雄性育性的了解不仅局限于遗传分析和细胞学水平,而且对细胞核不育的分子基础,以及细胞核不育的分子机理也有了一定的了解。本文旨在对细胞核雄性不育相关研究的进展情况进行简要综述。 Abstract:With the cloning of nuclear male fertility genes,learning of nuclear male fertility not only limited in genetic analysis and cell biology,but also advanced in molecular basis of male nuclear sterility and postulated in possible mechanisms of nuclear male sterility.The objectives of this paper are to review the related progress of plant nuclear male sterility.     

The mating consequences of sexual segregation within inflorescences of flowering plants

Many co-sexual plants segregate female and male function among flowers on an inflorescence through dichogamy or the production of unisexual flowers. Sexual segregation may reduce self-pollination among flowers within inflorescences (geitonogamy), thereby increasing the pollen available for export to other plants. To assess these complementary roles we manipulated the simultaneously hermaphroditic (adichogamous) flowers of Eichhornia paniculata to produce ten-flowered inflorescences with either female above male flowers (female/male inflorescences) or male/female inflorescences, which competed for mating opportunities with five-flowered adichogamous inflorescences. Because of the upward movement of bumble-bees, selfing increased upward in adichogamous inflorescences (overall female selfing rate s+/-s.e.=0.320+/-0.026). Female flowers of male/female inflorescences selfed less than flowers in corresponding positions in adichogamous inflorescences so s fell to 0.135+/-0.027. In contrast, all-female flowers of female/male inflorescences selfed similarly to upper flowers on adichogamous inflorescences, elevating s (0.437+/-0.043). During 1997, male/female inflorescences sired more outcrossed seeds than female/male or adichogamous inflorescences, whereas during 1994 flowers on male/female inflorescences received fewer visits than those of adichogamous inflorescences, reducing their outcross siring success. Hence, sexual segregation limits geitonogamy and enhances outcross siring success when it does not affect pollinator behaviour, illustrating the importance of both female and male function in inflorescence design.     

Effects of putative male pheromones on female ratings of male attractiveness: influence of oral contraceptives and the menstrual cycle

Previous research has revealed that natural and synthetic pheromones can enhance ratings of opposite sex attractiveness. The present study investigated the effects of exposure to male axillary secretions on female ratings of the sexual attractiveness of male stimuli. Thirty-two female undergraduates, half of whom were contraceptive pill users, rated male vignette characters and photographs of male faces on aspects of attractiveness. On two separate study days, corresponding to different phases of their menstrual cycle, stimuli were presented while exposed to male axillary pheromones and under a control condition (no pheromone). The order of testing was balanced with respect to pheromone/control condition and menstrual cycle phase. Pheromone exposure resulted in significantly higher attractiveness ratings of vignette characters and faces. Use of the contraceptive pill or menstrual cycle phase had equivocal effects on some vignette items and neither had any influence on female ratings of male facial attractiveness. The results of this study suggest that exposure to natural male axillary pheromones can significantly enhance female perceptions of various aspects of male attractiveness.     

Time course of androgenic modulation of odor preferences and odor cues in male meadow voles, Microtus pennsylvanicus.

During the breeding season, male meadow voles prefer female over male odors and females prefer male over female odors. Testosterone control of males' odor preferences and production of odors attractive to females differ. A male meadow vole's preference for female versus male odor was still evident 1 week after castration, but not 1 week later. This preference was reinstated in testosterone-treated male voles 2 weeks after the onset of hormone replacement. The attractiveness of male odors to females did not disappear until 3 weeks after castration. The attractiveness of male odors was reinstated 1 week after castrated males were treated with testosterone. The time course for the androgenic modulation of production of odors attractive to females may facilitate breeding. For example, at the end of the breeding season males may emit an odor that is still attractive to females. Similarly, at the beginning of the breeding season males may emit an odor that is attractive to females.     

No evidence for faster male hybrid sterility in population crosses of an intertidal copepod (Tigriopus californicus)

Two different forces are thought to contribute to the rapid accumulation of hybrid male sterility that has been observed in many inter-specific crosses, namely the faster male and the dominance theories. For male heterogametic taxa, both faster male and dominance would work in the same direction to cause the rapid evolution of male sterility; however, for taxa lacking differentiated sex chromosomes only the faster male theory would explain the rapid evolution of male hybrid sterility. It is currently unknown what causes the faster evolution of male sterility, but increased sexual selection on males and the sensitivity of genes involved in male reproduction are two hypotheses that could explain the observation. Here, patterns of hybrid sterility in crosses of genetically divergent copepod populations are examined to test potential mechanisms of faster male evolution. The study species, Tigriopus californicus, lacks differentiated, hemizygous sex chromosomes and appears to have low levels of divergence caused by sexual selection acting upon males. Hybrid sterility does not accumulate more rapidly in males than females in these crosses suggesting that in this taxon male reproductive genes are not inherently more prone to disruption in hybrids.     

A case report of a male rank reversal in a group of wild white-faced capuchins (Cebus capucinus)

During the course of a study of social relationships in wild, white-faced capuchins at Lomas Barbudal, Costa Rice (May 1990–May 1993), the alpha male was deposed by a subordinate male. The rank reversal was preceded by a decline in proximity maintenance by females to the alpha male, and an increase, in the amount of aggression directed toward the alpha male by the beta female and her female coalition partners. At the time of the rank reversal, females switched from giving thegargle vocalization exclusively to the old alpha male to gargling to the new alpha male; however, juveniles were less consistent with regard to which male they gargled to. At the time of the rank reversal, most adult females reduced the time spent in proximity and grooming with the old alpha male, and increased the time spent in proximity and grooming with the new alpha male. In contrast, juveniles' patterns of affiliation with males did not change in a predictable way following the reversal. The social strategies employed by capuchin monkeys during this rank reversal are compared with those of chimpanzees.     

An Ecological Theory of Sexual Dimorphism in Animals

Both male ornamentation and male combat result in increased male mortality. Because population sizes are limited by a carrying capacity, increased age-specific adult male mortality will result in decreased age-specific adult female mortality, as well as decreased juvenile mortality. As intersexual competition is one form of intraspecific competition, through choosing to mate with ornamented and/or combative males, females in polygamous systems reduce intraspecific competition. Because average male fitness must exactly equal average female fitness, male fitness will paradoxically rise with increasing male mortality. This theory also offers new perspectives on peripheral problems to sexual theory, such as mate location, resource guarding, leks, harems, and others.     

生态因子对赣南桉树枝瘿姬小蜂雄成虫比率的影响

桉树枝瘿姬小蜂Leptocybe invasa具有偏雌性的特点,了解桉树枝瘿姬小蜂的性比规律,有利于监测和掌控该蜂的种群动态,便于及时有效防控该蜂.2017年至2019年,采用在桉树Eucalyptus林中悬挂黄色粘虫板的方法,监测、观察桉树枝瘿姬小蜂成虫的发生动态,通过分析该蜂雄成虫比率及其影响因子,以弄清生态因子对...     

Patterns of interventions and the effect of coalitions and sociality on male fitness

In group living animals, especially among primates, there is consistent evidence that high-ranking males gain a higher reproductive output than low-ranking males. Primate studies have shown that male coalitions and sociality can impact male fitness; however, it remains unclear whether males could potentially increase their fitness by preferentially supporting and socializing with females. Here we investigate patterns of male interventions and the effect of coalitions and sociality on male fitness in rhesus macaques (Macaca mulatta) with particular focus on male-female interactions. We combined behavioural observations collected on Cayo Santiago with genetic data analysed for male reproductive output and relatedness. Our results revealed that the ten top-ranking males provided the majority of all male support observed. In contrast to other primates, male rhesus macaques mainly formed all-down coalitions suggesting that coalitions are less likely used to enhance male dominance. Males supporting females during and before their likely conception were not more likely to fertilize those females. We also found no evidence that males preferably support their offspring or other close kin. Interestingly, the most important predictor of male support was sociality, since opponents sharing a higher sociality index with a given male were more likely to be supported. Furthermore, a high sociality index of a given male-female dyad resulted in a higher probability of paternity. Overall, our results strengthen the evidence that sociality affects fitness in male primates, but also suggest that in species in which males queue for dominance, it is less likely that males derive fitness benefits from coalitions.