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。     

Male fertility and sex ratio at birth in red deer

Efforts to test sex ratio theory have focused mostly on females. However, when males possess traits that could enhance the reproductive success of sons, males would also benefit from the manipulation of the offspring sex ratio. We tested the prediction that more-fertile red deer males produce more sons. Our findings reveal that male fertility is positively related to the proportion of male offspring. We also show that there is a positive correlation between the percentage of morphologically normal spermatozoa (a main determinant of male fertility) and the proportion of male offspring. Thus, males may contribute significantly to biases in sex ratio at birth among mammals, creating the potential for conflicts of interest between males and females.     

Androgens prevent normally occurring cell death in a sexually dimorphic spinal nucleus

The spinal nucleus of the bulbocavernosus (SNB) contains many more motoneurons in adult male rats than in females. Androgens establish this sex difference during a critical perinatal period, which coincides with normally occurring cell death in the SNB region. Sex differences in SNB motoneuron number arise primarily because motoneuron loss is greater in females than in males during the early postnatal period. Perinatal androgen treatment in females attenuates cell death in the SNB region, reducing motoneuron loss to levels typical of males. The results suggest that steroid hormones determine sex differences in neuron number by regulating normally occurring cell death and that the timing of this cell death may therefore define critical periods for steroid effects on neuron number.     

Aggression in adult mice: modification by neonatal injections of gonadal hormones

Incidence of spontaneous aggression in adult male mice given a single injection of estradiol benzoate (0.4 milligram) when they were 3 days old was less than that of controls injected with oil. Aggressiveness was increased among adult females injected with either estradiol or testosterone propionate (1 milligram) at the same age. The increased aggressiveness noted among females given androgen was further documented during subsequent mating tests, when these females often attacked, wounded, and, in one case, killed naive males.     

Behavioral patterns of captive alpine musk deer: sex-specific behavior comparisons

The aim of this study was to document the behavior of captive alpine musk deer and to determine if daily behavior patterns varied between females and males. From August 2002 to January 2003, focal sampling was used to observe 32 adult captive alpine musk deer (13 female and 19 male) at Xinglongshan Musk Deer Farm (XMDF), Xinglongshan National Nature Reserve, Gansu Province. Results indicated similar behavior patterns for males and females, with only two out of 12 recorded behaviors showing significant sex differences. In comparison to females, males rested for a longer duration and exhibited tail pasting more frequently. This study also provided the first recording of tail pasting by female musk deer.     

烟蚜茧蜂Aphidins gifuensis Ashmead生物学研究Ⅱ．成虫生物学及越冬

烟蚜茧蜂在有雌雄两性存在的情况下，营两性生殖。未交配过的雌虫只生殖雄性后代。雌雄配对均可在２４ｈ内完成交配，交配过的雄蜂可再次支配，而雌蜂无此情况。雌蜂对蚜虫是否已被寄生并无分辨力，导致过寄生现象出现。过寄生程度随寄生的密度增大而减轻，反之则加重。雌蜂产卵对Ⅲ龄若蚜有明显的选择性。雌蜂１次仅产１粒卵，卵的孵化率高达９８％．成蜂寿命随温度升高而逐渐缩短，但饲喂以清水、蚜虫蜜露、１０％蜂蜜水均可使成蜂寿命延长。成蜂性比亦随温度和季节的不同而变异。兼性滞育。田间调查已发现其重寄生蜂７种。     

Extreme reversed sexual dichromatism in a bird without sex role reversal

Brilliant plumage is typical of male birds, reflecting differential enhancement of male traits when females are the limiting sex. Brighter females are thought to evolve exclusively in response to sex role reversal. The striking reversed plumage dichromatism of Eclectus roratus parrots does not fit this pattern. We quantify plumage color in this species and show that very different selection pressures are acting on males and females. Male plumage reflects a compromise between the conflicting requirements for camouflage from predators while foraging and conspicuousness during display. Females are liberated from the need for camouflage but compete for rare nest hollows.     

Physiological sex predicts hybrid sterility regardless of genotype

Reproductive isolation between biological species is characterized by Haldane's rule, which states that the heterogametic sex (XY or ZW) suffers the most dysfunctional effects of hybridization. It has been hypothesized that, in addition to X-linked recessive genes, Haldane's rule also reflects the faster evolution of genes related to male reproduction (faster-male evolution). We used sex-reversed hybrid Xenopus to test faster-male evolution by examining the fertility of sex-reversed individuals with the genotype of the inverse phenotypic sex. Hybrid males are sterile and hybrid females are fertile irrespective of their genotypic sex. Gene expression profiles match these adult phenotypes, and our results demonstrate that faster-male evolution is the most likely mechanism producing hybrid male sterility.     

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。     

棉大卷叶野螟雌虫性信息素对雄虫的诱集作用

为生物防治棉大卷叶野螟提供科学依据,研究棉大卷叶螟雌虫性信息素对雄虫的诱集作用,在野外和室内用棉大卷叶野螟雌虫及其性信息素提取物对雄虫进行诱集试验.研究发现:1～7日龄雌成虫及相应日龄雌成虫性信息素提取物随着日龄的增高,对雄蛾的引诱力逐渐降低;随着距离的加大,其诱集作用亦逐渐下降;1～7日龄雌成虫性信息素提取物对雄成虫...     

寄主大小及寄生顺序对蝇蛹佣小蜂寄生策略的影响

寄主大小模型认为寄生蜂后代性比与寄主大小相关,寄生蜂倾向于在大寄主上产出更多雌性后代,在小寄主上产出更多雄性后代。探讨了以家蝇蛹为寄主时,蝇蛹佣小蜂后代产量和性比变化;单次寄生情况下,寄主大小及寄生顺序对寄生蜂后代性比等影响。结果表明,蝇蛹佣小蜂的产卵期为(8.93±3.34) d,单头雌蜂能产雌性后代(34.11±16.34)头和雄性后代(11.04±8.87)头,且雄性百分比为0.24±0.11。随成蜂日龄的增大,寄生蜂产生雄性后代的比率显著增加。蝇蛹佣小蜂在寄生家蝇蛹时,会优先选择寄生个体较大的蛹;在单次寄生的情况下,蝇蛹佣小蜂倾向于在较大的家蝇蛹内产出更多的雌性后代。     

Extended male growth in a fossil hominin species

In primates that are highly sexually dimorphic, males often reach maturity later than females, and young adult males do not show the size, morphology, and coloration of mature males. Here we describe extended male development in a hominin species, Paranthropus robustus. Ranking a large sample of facial remains on the basis of dental wear stages reveals a difference in size and robusticity between young adult and old adult males. Combined with estimates of sexual dimorphism, this pattern suggests that male reproductive strategy focused on monopolizing groups of females, in a manner similar to that of silverback gorillas. However, males appear to have borne a substantial cost in the form of high rates of predation.     

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。     

微尾鼩年龄分布与性比研究

[目的]探究微尾鼩的年龄分布与性比,为进行种群数量预测奠定基础。[方法]将捕获于四川南充市郊的929只微尾鼩(434♂,495♀)分为4个年龄组,分析了12个月的微尾鼩性比、年龄组成及其季节动态。[结果]12月至次年2月为低数量期,种群中以亚成体组(Ⅰ)为主;4～9月为高数量期,雌、雄性都以成体二组(Ⅲ)为主。除亚成体组(Ⅰ)雄性略多于雌性以外,捕获的雌性个体多于雄性(♂/♀为0.88),但经过卡方检验各组性比均符合1∶1的比例。在调查期间,各月的性比♂/♀值在0.64～2.00,9月捕获的雌性个体比雄性多46.67%,差异显著。[结论]微尾鼩越冬个体以亚成体组(Ⅰ)为主,各年龄组性比为1∶1。     

Sex attractant of the grass grub beetle

The sex attractant produced by adult females of the grass grub beetle Costelytra zealandica (White) has been isolated and identified as phenol. Field tests with phenol-water mixtures were attractive to male beetles in particular.     

花曲柳窄吉丁潜在飞行能力初步研究

为了评估花曲柳窄吉丁的飞行潜能,利用昆虫飞行磨系统测定雌雄花曲柳窄吉丁成虫在不同光照时间、交配状态、取食状态和日龄条件下的飞行能力。结果表明:雌虫24 h内最远飞行距离5 500 m,雄虫最远飞行距离1 397 m,雌雄成虫 间飞行距离差异显著;雌虫在24 h光照时间下飞行距离比L/D(昼/夜)=16 h/8 h光照周期下更远;交配雌虫与未交配雌虫在飞行距离上有显著差异,交配后雌虫飞行距离更远,而交配对雄虫飞行能力无显著影响;经取食并休息的雌虫飞行距离显著大于不取食不休息的雌虫;不同日龄未取食的花曲柳窄吉丁雌虫飞行能力存在一定差异,1日龄飞行能力最弱,13日龄最强,从1~2日龄开始飞行距离增加,2~4日龄飞行距离随日龄增加而减少,而在4日龄后飞行距离又随着日龄的增加而增加。说明花曲柳窄吉丁具有较长距离飞行的潜能,这可为该虫的传播扩散和风险评估提供一定依据。      

Co-γ辐射对烟青虫飞翔和繁殖生物学的影响

 为了解杂交稻不育系抽穗不畅问题，以隐性长穗颈温敏核不育水稻长选3S为材料，采用田间调查和人工温度处理方法研究了温度对隐性长穗颈基因（eui）表达的影响。结果表明，长选3S穗颈伸出剑叶叶鞘的长度与始花前9～20 d自然条件下的日均温度呈负相关，其中以始花前12～17 d(花粉母细胞形成至减数分裂期)日均温度负相关性最显著。在eui基因表达对温度最敏感的时期进行4种人工温度处理，22℃、24℃、26℃和28℃。28℃条件下eui基因表达受阻；22～26℃条件下eui基因表达，且穗颈伸出剑叶叶鞘的长度随温度降低而增长。     

Plasma testosterone levels in the male rhesus: influences of sexual and social stimuli

Four adult male rhesus monkeys were provided access individually to a group of receptive females. Each male assumed dominance and engaged in frequent copulations. Plasma testosterone levels increased two- to threefold during this period. Next, each male was subjected to sudden and decisive defeat by a large all-male group, and plasma testosterone fell following this experience. Two males were later reintroduced to the females, and plasma testosterone rose rapidly to the previous elevated levels.     

所罗门群岛海域长鳍金枪鱼繁殖生物学初步研究

根据2012年9-12月所罗门群岛海域采集的307尾长鳍金枪鱼样本,分析其性别比、性腺成熟度和性腺指数等繁殖生物学参数。结果表明：繁殖群体总性别比和性成熟个体性别比均不符合1：1（P〈0．05）,雄性个体比例大于雌性,性别比在产卵期间出现一定波动,但普遍小于1：1。性别比与个体大小密切相关,雄性比例随叉长增长而降低。性成熟度分析表明,产卵期间性成熟个体比例达到70％以上,其中存在大量的产卵后群体,未成熟比例较低。雌性不同性成熟度大小差异明显（P〈0．05）,但雄性并不明显（P〉0．05）。相同性成熟度雄性个体平均叉长均大于雌性,但并没有体现出一致的变化。雌、雄个体初次性成熟叉长分别为84．88cm和85．61cm。性腺指数（Gsi）在各性成熟度和叉长组间存在显著差异（P〈0．05）,雌性GSI大于1．2几乎全部为成熟个体,尤其GSI大于2普遍为即将产卵（V期）和产卵后（Ⅵ期）群体;雄性个体GSI普遍小于2,各叉长组雌性GSI普遍高于雄性,这表明雌性性腺发育较快。而调查期间9月GSI均值明显高于其他3月（P〈0．05）,综合分析认为该海域长鳍金枪鱼9—10月达到产卵高峰期。