Sex pheromone of the queen butterfly: biology

Males of the queen butterfly Danaus gilippus berenice, deprived of the two extrusible brushlike "hairpencils" at the rear of their abdomen, are capable of courting females but incapable of seducing them. In normal courtship, an aphrodisiac secretion associated with the hairpencils is transferred by way of tiny cuticular "dust" particles to the antennae of the females. Of the two substances identified from the secretion, one (the ketone) acts as the chemical messenger that induces the females to mate. The only known function of the other compound (the diol) is to serve as a glue that sticks the dust to the female. Males were reared under conditions in which they produced subnormal amounts of ketone and showed reduced seductive capacity. Under certain experimental circumstances, the competence of these males was restored by addition of synthetic ketone.     

Integrating multispectral reflectance and fluorescence imaging for defect detection on apples

This research investigated multispectral imaging to detect various defects on apples. An integrated approach using multispectral imaging in reflectance and fluorescence modes was used to acquire images of three varieties of apples. Eighteen images from a combination of filters ranging from the visible region through the NIR region and from three different imaging modes (reflectance, visible light induced fluorescence, and UV induced fluorescence) were acquired for each apple as a basis for pixel-level classification into normal or disorder tissue. Artificial neural network classification models were developed for two classification schemes, a two-class and a multiple-class. In the two-class scheme, pixels were categorized into normal or disordered tissue, whereas in the multiple-class scheme, pixels were categorized into normal, bitter pit, black rot, decay, soft scald, and superficial scald tissues. A 10-fold cross validation technique was used to assess the performance of the neural network models. The integrated imaging model of reflectance and fluorescence was effective on Honeycrisp variety, whereas single imaging models of reflectance or fluorescence was effective on Redcort and Red Delicious. The technique is promising for accurate recognition of different types of disorder on apple.     

Sperm-female coevolution in Drosophila

Rapid evolution of reproductive traits has been attributed to sexual selection arising from interaction between the sexes. However, little is known about the nature of selection driving the evolution of interacting sex-specific phenotypes. Using populations of Drosophila melanogaster selected for divergent sperm length or female sperm-storage organ length, we experimentally show that male fertilization success is determined by an interaction between sperm and female morphology. In addition, sperm length evolution occurred as a correlated response to selection on the female reproductive tract. Giant sperm tails are the cellular equivalent of the peacock's tail, having evolved because females evolved reproductive tracts that selectively bias paternity in favor of males with longer sperm.     

Progress in studies of sex determination mechanisms and sex control techniques in Cynoglossus semilaevis (half-smooth tongue sole)

The Cynoglossus semilaevis (half-smooth tongue sole) is a marine flatfish of great commercial value for fisheries and aquaculture in China. It has a female heterogametic sex determination system (ZW/ZZ) and environmental factors can induce sex-reversal of females to phenotypic males, suggesting that it is a promising model for the study of sex determination mechanisms. Additionally, females grow much faster than males and it is feasible to improve the aquaculture production through sex control techniques. This paper reviews the progress in research on sex determination mechanisms research in our laboratory. We have completed whole-genome sequencing and revealed the genome organization and sex chromosome evolution of C. semilaevis. A putative male determining gene dmrt1 was identified and DNA methylation was verified as having a crucial role in the sex reversal process. Genetic maps and sex-specific biomarkers have been used in a marker-assisted selection breeding program and for differentiation of the fish sex. Development and improvement of sex control technologies, including artificial gynogenesis and production of breeding fry with high proportion of females, is also reviewed. These research advances have provided insight into the regulation of sex determination and enabled efficient sex management in artificial culturing of C. semilaevis.     

南海鸢乌贼微型群肌肉和性腺组织能量积累及其分配

利用组织能量密度测定技术和残差指标分析方法,分析了南海鸢乌贼微型群个体肌肉组织和性腺组织的能量积累及其分配规律的变化过程。结果显示,微型群个体的肌肉、性腺组织之间的能量密度存在显著性差异;除缠卵腺之外,其它组织的能量密度均随性腺发育变化显著。肌肉组织和性腺组织的组织能量积累均随性腺发育增加显著。同一性腺成熟度等级,肌肉组织的相对组织能量积累较高,性腺组织的相对组织能量积累相对较低。雌性个体性腺组织相对组织能量积累随着性腺发育增长显著,雄性个体性腺组织相对组织能量积累在Ⅰ期~Ⅴ期增长较快,在Ⅵ期~Ⅶ期趋于稳定。肌肉和性腺组织在性腺发育后期的质量特征较发育前期均显著改善,并且肌肉组织能量积累-胴长残差与性腺组织能量积累-胴长残差呈显著的正相关关系,表明性腺发育过程中的肌肉组织与性腺组织之间不存在能量交流。研究表明,南海鸢乌贼微型群个体的生殖能量倾向于外源性投入,肌肉和性腺组织的组织能量密度、组织能量积累和相对组织能量积累存在雌雄差异性。     

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.     

Essential role of Fkbp6 in male fertility and homologous chromosome pairing in meiosis

Meiosis is a critical stage of gametogenesis in which alignment and synapsis of chromosomal pairs occur, allowing for the recombination of maternal and paternal genomes. Here we show that FK506 binding protein (Fkbp6) localizes to meiotic chromosome cores and regions of homologous chromosome synapsis. Targeted inactivation of Fkbp6 in mice results in aspermic males and the absence of normal pachytene spermatocytes. Moreover, we identified the deletion of Fkbp6 exon 8 as the causative mutation in spontaneously male sterile as/as mutant rats. Loss of Fkbp6 results in abnormal pairing and misalignments between homologous chromosomes, nonhomologous partner switches, and autosynapsis of X chromosome cores in meiotic spermatocytes. Fertility and meiosis are normal in Fkbp6 mutant females. Thus, Fkbp6 is a component of the synaptonemal complex essential for sex-specific fertility and for the fidelity of homologous chromosome pairing in meiosis.     

Competition Among Courting Male Moths: Male-to-Male Inhibitory Pheromone

The behavioral function of a pheromone released by males of the army-worm moth Pseudaletia unipuncta was investigated both in laboratory wind-tunnel experiments and in experiments with moth-baited traps in the field. Such male moth scents have been thought to act at close range as sexual stimulants for females of the same species. However, the only obvious effect of the P. unipuncta male pheromone was upon other males, decreasing their tendency to approach sexually receptive, pheromone-releasing females and to exhibit copulatory behavior when near those females. The adaptive significance of the male pheromone may be related to the increased reproductive efficiency that results if multiple males are prevented from competing for a single female.     

Evolutionary ecology of the prezygotic stage

The life cycles of sexually reproducing animals and flowering plants begin with male and female gametes and their fusion to form a zygote. Selection at this earliest stage is crucial for offspring quality and raises similar evolutionary issues, yet zoology and botany use dissimilar approaches. There are striking parallels in the role of prezygotic competition for sexual selection on males, cryptic female choice, sexual conflict, and against selfish genetic elements and genetic incompatibility. In both groups, understanding the evolution of sex-specific and reproductive traits will require an appreciation of the effects of prezygotic competition on fitness.     

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).     

美国白蛾触角感器超微结构

为研究美国白蛾(Hyphantria cunea)触角感器与其嗅觉感受机制的关系,借助扫描电镜观察了其触角感器类型及其分布。结果显示:美国白蛾雌蛾触角为锯齿状,雄蛾触角为双栉齿状,也称羽毛状;在雌雄触角上共发现10种类型感器,即长毛形感器Ⅰ(ST-Ⅰ)、短毛形感器Ⅱ(ST-Ⅱ)、刺形感器(SCH)、锥形感器(SB)、栓锥形感器(SST)、具缘毛腔锥形感器Ⅰ(SCO-Ⅰ)、无缘毛腔锥形感器Ⅱ(SCO-Ⅱ)、鳞形感器(SSQ)、B hm氏鬃毛(BB),以及一种新型感器——舌形感器(SL)。毛形感器数量最多,且雄蛾多于雌蛾。雌雄蛾同类感器中除SCO-I雌雄差异不显著外,其余感器类型长度雌雄均差异显著,其中,雌蛾SST及SCO-Ⅱ长度均显著大于雄蛾,ST-Ⅰ、ST-Ⅱ、SCH、SB及SSQ长度均为雄蛾显著大于雌蛾。SL仅分布于雄蛾羽状分支腹面,SSQ位于雌雄触角纵轴及分支背面,BB位于雌雄触角柄节两侧,其余感器均分布于雌雄触角腹面。     

Evolution and development of sex differences in cooperative behavior in meerkats

In cooperatively breeding birds, where helpers of both sexes assist with the provisioning and upbringing of offspring who are not their own, males tend to contribute more than females to rearing young. This sex difference has been attributed to paternity uncertainty, but could also occur because males contribute more where they are likely to remain and breed in their group of origin. In contrast to most birds, female meerkats (Suricata suricatta) are more likely to breed in their natal group than males. We show that female meerkat helpers contribute more to rearing young than males and that female helpers feed female pups more frequently than males. Our results suggest that sex differences in cooperative behavior are generated by sex differences in philopatry and occur because females derive greater direct benefits than males from raising recruits to their natal group. These findings support the view that direct, mutualistic benefits are important in the evolution of specialized cooperative behavior.     

Female-Female Pairing in Western Gulls (Larus occidentalis) in Southern California

Pairs of females that remain together from one year to the next are associated with the presence of supernormal clutches in western gull nests. Intervals between laying of eggs in supernormal clutches are less than those found in normal clutches, a result indicating both females in a pair contribute to the clutch. Most eggs in supernormal clutches are infertile. The pairs of females occupy territories that are not shared with a resident male. In three homosexual pairs one of the females exhibited behaviors normally ascribed only to males.     

Combining leaf fluorescence and active canopy reflectance sensing technologies to diagnose maize nitrogen status across growth stages

Rapid methods allowing for non-destructive crop monitoring are imperative for accurate in-season nitrogen (N) status assessment and precision N management. The objectives of this paper were to (1) compare the performance of a leaf fluorescence sensor Dualex 4 and an active canopy reflectance sensor Crop Circle ACS-430 for estimating maize (Zea mays L.) N status indicators across growth stages; (2) evaluate the potential of N status prediction across growth stages using the reflectance parameters acquired from the canopy sensor at an early growth stage; and, (3) investigate the prospect of combining the active canopy sensor and leaf fluorescence sensor data to estimate N nutrition index (NNI) indirectly using a general model across growth stages. The results indicated that data from both sensors were closely related to NNI across stages. However, using the direct NNI estimation method, among the tested indices, only the N balance index (NBI) could diagnose N status satisfactorily, based on the Kappa statistics. The effect of growth stages on proximal sensing was reduced by incorporating the information of days after sowing. It was found that the leaf fluorescence sensor performed relatively better in estimating plant N concentration whereas the canopy reflectance sensor performed better in aboveground biomass estimation. Their combination significantly improved the reliability of N diagnosis, including NNI prediction. In addition, the study confirmed that N status can be assessed by predicting aboveground biomass at the later stages using the canopy reflectance measurements at an early stage. Furthermore, the integrated NBI was verified to be a more robust and sensitive N status indicator than the chlorophyll concentration index. It is concluded that combining active canopy sensor data, of an early growth stage (e.g. V8), with leaf fluorescence sensor data, modified using days after sowing, can improve the accuracy of corn N status diagnosis across growth stages.

     

Temporal and spatial changes of chlorophyll fluorescence as a basis for early and precise detection of leaf rust and powdery mildew infections in wheat leaves

Temporal and spatial changes in parameters of fast chlorophyll fluorescence kinetics (ground fluorescence, Fo and maximal fluorescence, Fm) and red/NIR reflectance were assessed with a Pulse-Amplitude-Modulated (PAM)-Imaging system on a daily basis over a period of 2 weeks following inoculation of wheat leaves with powdery mildew and leaf rust. The early detection of these infections by means of fluorescence imaging was possible 2–3 days before visual symptoms or significant changes in normalised-differenced-vegetation index (NDVI) became apparent. The initial infection of both fungi caused an increase in Fo and decrease in photochemical efficiency (Fv/Fm, Fv/Fo). The appearance and development of fungal pustules was accompanied by reduction in Fo and Fm. This resulted mainly from lower absorption of fluorescence exciting light by the leaf mesophyll due to the shielding effect of fungal mycelium, and to lesser extent from the chlorophyll breakdown underneath pustules. Among the evaluated fluorescence parameters, Fv/Fo displayed the most pronounced response to both kinds of infection. Mildew infection influenced chlorophyll fluorescence neither in the direct vicinity of mycelium nor in the apparently healthy leaf regions. Rust infected plants, in contrast, displayed significantly reduced photochemical efficiency Fv/Fm and Fv/Fo in chlorotic tissue around pustules. The same, but less pronounced tendency was found in the apparently healthy regions of rust infected leaves in the last days of the experiment. Dark adaptation of leaves proved to be necessary for accurate detection of both pathogen infections by means of fluorescence imaging. Additional experiments are needed to estimate the potential of this technique for remote sensing under field conditions.     

Pheromone Concentration as a Mechanism for Reproductive Isolation between Two Lepidopterous Species

Pheromone-releasing females of the closely related noctuid moths Trichoplusia ni and Autographa californica attract mainly males of their own species. Sex-pheromone-concentration specificity appears to be an important reproductive isolating mechanism for these two species. Apparently, both species utilize the same pheromone, cis-7-dodecenyl acetate, for mating communication, but T. ni utilizes a higher level than does A. californica. Traps releasing amounts of cis-7-dodecenyl acetate that are highly attractive for males of one of the species catch very few males of the other species.     

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。     

Relative Fecundity and Parental Effort in Communally Nesting Anis, Crotophaga sulcirostris

The contribution of eggs to the communal clutch by females of the group and the genetic contribution by males of the group are significantly skewed. The amount of parental care performed by each bird is correlated with relative egg ownership for both sexes.     

不同性别和交配状态的马铃薯块茎蛾对马铃薯挥发物的触角电位反应

[目的]探明不同性别和交配状态的马铃薯块茎蛾(Phthorimaea operculella)对寄主植物(马铃薯)挥发物的电生理反应的差异,为利用化学生态手段防治马铃薯块茎蛾提供参考.[方法]利用触角电位技术(electroantennogram,EAG),测定未交配雌蛾、交配雌蛾、未交配雄蛾3种不同生理状态的马铃薯块...