Mosquitoes: female monogamy induced by male accessory gland substance

Male accessory glands were implanted in virgin females of Aedes aegypti. When exposed to males, females copulated readily but were not inseminated; they remained sterile for life. Extract from one male could sterilize more than 64 females. The active principle may be a protein or peptide. Intraspecific transplant prevented insemination in 12 species, including Aedes, Anopheles, and Culex; interspecific transplant gave partial protection.     

Incidence of sex chromatin in Gallus domesticus

The presence of so-called sex chromatin has been demonstrated in the interphase nuclei of the cells of the domestic chicken (Gallus domesticus). Definite sex dimorphism was observed for the incidence of this nuclear component; the frequency of its occurrence in females was at least ten times that of its occurrence in the males, ranging from 22 percent in the duodenal muscle cells to 52 percent in the epidermal cells of a growing feather.     

Sex Discrimination in Gerris remigis: Role of a Surface Wave Signal

Even when blinded with masks, adult male water striders (Gerris remigis) accurately ascertain the sex of other adult water striders in the laboratory. Freely moving females that were artificially made to play back computer-generated male surface wave and body-contact signals of about 90 waves per second were treated as males by the masked males and as females when no such playbacks were made. Thus, the males can use presence or absence of the male signal as the sole means for sex discrimination.     

Evidence for an antiaphrodisiac in the sweat bee Lasioglossum (Dialictus) zephyrum

Male Lasioglossum (Dialictus) zephyrum in the field are attracted to models impregnated with the odor of virgin females. The number of males responding increases with increasing odor concentration. Once a male has contacted a model, its attractiveness to other males is reduced, suggesting that the male may contribute an antiaphrodisiac cue so that other males avoid mated females.     

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.     

Asymmetries in mating preferences between species: female swordtails prefer heterospecific males

In male swordtails ((Xiphophorus nigrensis)) there are three size classes that derive from allelic variation at the pituitary locus on the Y chromosome. Progeny analysis and preference tests suggest that females prefer to mate with larger males. In the closely related X. pygmaeus, there is no allelic variation at this locus; this species consists of males similar in size only to smaller X. nigrensis males. In addition to being smaller than most X. nigrensis males, these X.pygmaeus males also lack both the swordtail and a major component of the courtship display common in most X. nigrensis males. Usually, female X. pygmaeus prefer to mate with heterospecific males rather than conspecifics, regardless of body size and the presence of a swordtail. However, the smallest X. nigrensis males lack the same courtship component as do the X. pygmaeus males, and in this comparison female X. pygmaeus show no preference. Although sexual selection, through its action on divergence of courtship displays, has been implicated as a factor leading to speciation, in this case sexual selection could lead to the congealing of gene pools between heterospecifics.     

淮南麻黄鸡生长曲线分析与拟合的研究

对淮南麻黄鸡１￣１８０日龄生长曲线进行了分析和非线性曲线拟合研究,结果表明,淮南麻黄鸡公、母鸡在６０日龄前生长曲线基本一致,之后公鸡则明显高于母鸡,且保持较长时间的快速生长状态,Ｌｏｇｉｓｔｉｃ模型和Ｇｏｍｐｅｒｔｚ模型均能很好地拟合淮南麻黄鸡公鸡的生长曲线（Ｒ＾２分别为０．９９８９和０．９９９８）和母鸡的生长曲线（Ｒ＾２分别为０．９９５１和０．９９８１）,但Ｇｏｍｐｅｒｔｚ模型在拟合度和预测体重     

甲基丁香酚挥发物对桔小实蝇成虫的引诱作用

[目的]研究甲基丁香酚对桔小实蝇成虫的引诱效果。[方法]利用Y型嗅觉仪测试了不同生理状态下(性成熟与性未成熟)桔小实蝇两性成虫在不同时间内(5、10、15、20、30、40、50和60 min)对不同剂量甲基丁香酚(0.001、0.010、0.1000、1.000和10.000 mg)挥发物的反应。[结果]甲基丁香酚对桔小实蝇对性成熟雄虫有显著引诱作用,但对性成熟雌虫及雄虫、性未成熟雄虫均无引诱作用。测试剂量为0.001 g时性成熟雄虫在10 min时即对甲基丁香酚产生显著反应;在测试剂量达到0.01 g以上时,性成熟雄虫均在5min时即产生显著反应。[结论]甲基丁香酚仅对性成熟雄虫有引诱作用,对性未成熟雄虫、未成熟雌虫、成熟雌虫无引诱作用。     

红脂大小蠹雄性配偶选择行为及其对生殖的影响

为研究红脂大小蠹(Dendroctonus valens)雄性能否依据信息素对雌性进行选择,以及这种选择行为对生殖的影响,首先使用Y-型嗅觉仪验证这种选择行为,然后用玻璃夹板技术分析雄性对其选择(P)和未选择(NP)的雌性在求偶和交配行为上的差异,最后用木段接种技术研究雄性与P雌性和NP雌性配对后在坑道构筑、产卵和幼虫发育上的差异。结果表明,雄性对雌性有着显著的基于信息素的选择行为。在求偶和交配行为上,雄性对P雌性更易求偶成功,交配时间更长(P0.05)。当雄性和P雌性配对时,前10 d筑出更长的且更清洁的坑道(P0.05)。20 d时,P雌性后代中孵化幼虫占后代总数量的比例极显著高于NP雌性(P0.001)。30 d时,P雌性的幼虫质量极显著高于NP雌性(P0.001)。以上结果表明,红脂大小蠹存在基于信息素的雄性配偶选择行为,其对生殖产生显著影响。     

Selection, outbreeding depression, and the sex ratio of scale insects

The black pineleaf scale insect has haploid males and diploid females. Ratios of males to females late in development ranged from 0.005 to 0.320 among insect subpopulations that were infesting different host trees. Demes well adapted to an individual ponderosa pine had a higher proportion of males than did demes that were poorly adapted to the host. Ratios of males to females rose in successive annual samples as natural selection increased insect adaptation. Gene flow between demes on different host trees produced predictable changes in the sex ratio.     

Female mate choice in a neotropical frog

Female Physalaemus pustulosus choose their mates and are more likely to choose larger males. There is a significant negative correlation between the size of the male and the fundamental frequency of one of the components of its advertisement call. Playback experiments demonstrate that females are capable of choosing larger males by distinguishing among differences in spectral components of the advertisement call.     

成都白鸡快、慢羽纯系的选育及羽型研究

1982年我室就成都白鸡羽型,快,慢羽纯系的选育、K(慢)、k(快)基因频率及杂种鸡羽速自别雌雄的准确率等进行了研究。按主翼羽和覆主翼羽生长状况,该鸡种初生雏羽型分为:快羽一型,慢羽三型。K(慢),k(快)基因频率分别为0.1602和0.8398。表型鸡经测交,纯繁选育出成都白鸡快,慢羽两个品系。以成都白鸡慢羽母鸡同快羽京白公鸡杂交,其杂种鸡羽速自别雌雄的准确率为99.13%。     

Transmission characteristics of Tomato chlorosis virus (ToCV) by Bemisia tabaci MED and its effects on host preference of vector whitefly

The epidemiology of Tomato chlorosis virus(ToCV) in China is closely associated with its vector whitefly, Bemisia tabaci(Gennadius) MED. However, the transmission characteristics of ToCV by B. tabaci MED remain poorly understood. In this study, we analyzed: 1) the horizontal and vertical transmission of ToCV by B. tabaci MED whiteflies; 2) the acquisition of ToCV by male and female B. tabaci MED whiteflies after different feeding durations; 3) the transmission efficacy of viruliferous male and female B. tabaci MED whiteflies after different inoculation access periods(IAPs); 4) the retention of ToCV by viruliferous male and female B. tabaci MED whiteflies after a 48 h acquisition access period(AAP); and 5) the effects of ToCV on host choice of healthy or ToCV-infected tomato plant of viruliferous and non-viruliferous B. tabaci MED at different time points. Our results showed that: 1) viruliferous males could not transfer ToCV to non-viruliferous females, and vice versa, viruliferous females could not pass on ToCV to non-viruliferous males. ToCV could not be detected in the F1 generation adults; 2) ToCV could be detected within 4.0% of females or males after a 20 min AAP; 3) ToCV could be detected in 33.3% of tomato plants inoculated by 10 viruliferous males or females with IAPs of 20 or 30 min; 4) the maximum retention time in females was 7 and 5 days in males; and 5) non-viruliferous B. tabaci MED did not show a preference for ToCV-infected tomato plants or healthy tomato plants. However, viruliferous B. tabaci MED whiteflies did prefer to settle on healthy tomato plants over ToCV-infected tomato plants. These findings will be helpful to better understand the epidemiology of the recently emerged plant virus, ToCV, in tomato fields in China.     

艾维茵肉仔鸡生长规律的模拟及最大经济效益点的研究

以商品代艾维茵肉鸡为材料，研究了公母鸡０－８周龄体重，饲养费用的变化。首选运用Ｇｏｍｐｅｒｔｚ生长模型对公母肉用仔鸡的生长曲线进行拟合，而后运用技术经济学中的边际平衡原理来确定公母肉用仔鸡的最佳出栏时间。结果表明；公肉用仔鸡的极限体重，拐点时间和拐点体重均大于母鸡，达到增重高峰的时间较晚。     

Reproductive social behavior: cooperative games to replace sexual selection

Theories about sexual selection can be traced back to Darwin in 1871. He proposed that males fertilize as many females as possible with inexpensive sperm, whereas females, with a limited supply of large eggs, select the genetically highest quality males to endow their offspring with superior capabilities. Since its proposal, problems with this narrative have continued to accumulate, and it is our view that sexual selection theory needs to be replaced. We suggest an approach that relies on the exchange of direct ecological benefits among cooperating animals without reference to genetic benefits. This approach can be expressed mathematically in a branch of game theory that pertains to bargaining and side payments.     

Social complexity in chinese coastal neolithic sites

Neolithic cemeteries in Zhejiang, Jiangsu, and Shandong provinces from about 5000 to 2000 B.C. show increases in the mean numbers of burial goods, goods found with males, and tools used as grave goods; separation of burial localities; differentiation of sets of tools found with males and females; a decrease in goods found with children; and common ornaments found with males and females. The distribution of tools seems to reflect a sexual division, with an increase in the prominence of males which may be associated with intensification of cultivation. Emergence of ranking is suggested by very rich graves and ornaments shared by males and females. Chinese theories of cultural evolution are introduced.     

Adaptation in a plant-hummingbird association

Sexual dimorphism in bill morphology and body size of the Caribbean purple-throated carib hummingbird is associated with a reversal in floral dimorphism of its Heliconia food plants. This hummingbird is the sole pollinator of H. caribaea and H. bihai, with flowers of the former corresponding to the short, straight bills of males, the larger sex, and flowers of the latter corresponding to the long, curved bills of females. On St. Lucia, H. bihai compensates for the rarity of H. caribaea by evolving a second color morph with flowers that match the bills of males, whereas on Dominica, H. caribaea evolves a second color morph with flowers that match the bills of females. The nectar rewards of all Heliconia morphs are consistent with each sex's choice of the morph that corresponds to its bill morphology and energy requirements, supporting the hypothesis that feeding preferences have driven their coadaptation.     

青杨脊虎天牛成虫交配行为及化学通讯方式

对青杨脊虎天牛(Xylotrechus rusticus Linnaeus)成虫交配行为的观察和Y型管生测仪的生测研究表明,释放化学信息是引起青杨脊虎天牛成虫交尾的主要通讯方式.利用气相色谱-质谱联用对试虫正己烷提取物的定性检测,进一步证明了雌虫释放短距离性信息素,雄虫接触后释放较长距离挥发性物质的推断.雄虫释放的化学物质通过空气传递给雌虫,而后进行交尾.     

Female moorhens compete for small fat males

Female moorhens in flocks competed with each other to obtain mates. The heaviest females won most of the agonistic encounters, and these females paired with males that had large fat reserves. Fat males tended to be small, possibly because of energetic constraints on birds of large body size. Females paired with fat males initiated more nesting attempts in a season.     

Evidence for ecological causation of sexual dimorphism in a hummingbird

Unambiguous examples of ecological causes of animal sexual dimorphism are rare. Here we present evidence for ecological causation of sexual dimorphism in the bill morphology of a hummingbird, the purple-throated carib. This hummingbird is the sole pollinator of two Heliconia species whose flowers correspond to the bills of either males or females. Each sex feeds most quickly at the flower species approximating its bill dimensions, which supports the hypothesis that floral specialization has driven the evolution of bill dimorphism. Further evidence for ecological causation of sexual dimorphism was provided by a geographic replacement of one Heliconia species by the other and the subsequent development of a floral dimorphism, with one floral morph matching the bills of males and the other of females.