New Permian Insects Discovered in Kansas and Oklahoma

In addition to the viviparous fish Mollienesia formosa, two other species of poeciliids have recently been found to produce only female offspring. The young of these females, however, unlike those of M. formosa, inherit characteristics from any one of the several species of males used in experimental matings.     

"Sex-ratio" condition: unusual mechanisms in bark beetles

Although males and females occur in similar frequency in the broods of most scolytid beetles, certain individuals of several species produce offspring highly aberrant in the ratio of sexes-all or mostly female. In some instances this condition reflects gynogenesis (parthenogenesis stimulated by mating); in others, a maternally transmitted factor.     

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.     

长春市一新外来入侵物种--白蜡虫的生物学特性与种群控制研究

首次报道了白蜡虫在长春市的分布。经观察,白蜡虫在长春市1年发生1代,以受精雌虫在水蜡树枝上越冬。4月中旬雌虫开始活动,5月上旬至5月下旬为卵期,6月上旬卵开始孵化。初孵若虫经1周后在水蜡树叶片上固定取食。2龄若虫在枝条上为害,至8月下旬羽化成虫。雌虫经交尾后越冬。对2龄若虫进行化学防治试验表明,以体积分数为3%顺式氯氰菊酯1:3 000~7 000倍液和40%毒死蜱1:800~1 000倍液进行喷雾防治,防治效果均可达到99%。     

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).     

Developmental plasticity in sexual roles of butterfly species drives mutual sexual ornamentation

Current explanations for why sexual ornaments are found in both sexes include genetic correlation, same sex competition, and mutual mate choice. In this study, we report developmental plasticity in mating behavior as induced by temperature during development in the butterfly Bicyclus anynana. Males and females reciprocally change their sexual roles depending on their larval rearing temperatures. This switch is correlated with a change in mating benefits to females and costs to males. The discrete seasonal environments, wet season and dry season, are known to produce the two developmental forms and as a consequence impose alternating, symmetrical patterns of sexual selection, one season on male ornaments, the following season on female ornaments. Thus, reciprocal selection through time may result in mutual sexual ornamentation.     

Neural mechanisms for the coordination of duet singing in wrens

Plain-tailed wrens (Pheugopedius euophrys) cooperate to produce a duet song in which males and females rapidly alternate singing syllables. We examined how sensory information from each wren is used to coordinate singing between individuals for the production of this cooperative behavior. Previous findings in nonduetting songbird species suggest that premotor circuits should encode each bird's own contribution to the duet. In contrast, we find that both male and female wrens encode the combined cooperative output of the pair of birds. Further, behavior and neurophysiology show that both sexes coordinate the timing of their singing based on feedback from the partner and suggest that females may lead the duet.     

Copulatory vocalizations of chacma baboons (Papio ursinus), gibbons (Hylobates hoolock), and humans

The copulatory vocalizations of female baboons (Papio ursinus) are more complex than those of female gibbons (Hylobates hoolock) or human females. Adult males of all these species begin calling later than the female, but subordinate baboon males do not call. Copulatory vocalizations may serve to mutually stimulate the mating partners or to incite male competition.     

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.     

Mate Selection and Behavioral Thermoregulation in Fowler's Toads

Male Fowler's toads produce mating calls that are affected by the body size and temperature of the caller. Females are able to discriminate between variations in these calls and select the largest available males. By thermoregulation, males are able to alter their calls to make them more attractive to females.     

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.     

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.     

Haploid females in the parasitic wasp Nasonia vitripennis

The insect order of Hymenoptera (ants, bees, sawflies, and wasps) consists almost entirely of haplodiploid species. Under haplodiploidy, males develop from unfertilized eggs and are haploid, whereas females develop from fertilized eggs and are diploid. Although diploid males commonly occur, haploid females have never been reported. In analyzing the phenomenon of gynandromorphism in the parasitoid wasp Nasonia vitripennis, we found a line that generates complete phenotypic females from unfertilized eggs. These females have ovaries, can lay eggs, and are haploid, as shown by cytological and flow cytometric analyses. The data show that diploidy is not necessary for female development.     

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。     

Male Esterase 6 Catalyzes the Synthesis of a Sex Pheromone in Drosophila melanogaster Females

Esterase 6, a component of the seminal fluid of Drosophila melanogaster males, hydrolyzes cis-vaccenyl acetate, a lipid made only by males, to cis-vaccenyl alcohol. This reaction occurs in the female reproductive tract and is virtually complete within 6 hours after copulation. Both the alcohol and the acetate decrease the number of matings among pairs of virgin flies in which the female is treated topically with these substances. Although females tested 10 minutes after copulation elicit less courtship than virgin females, females tested 6 hours after copulation stimulate even less courtship if they received active esterase 6 in the seminal fluid of their respective mates. Either the alcohol or a derivative appears to be an antiaphrodisiac that decreases courtship elicited by inseminated females and thus reduces the probability of further mating. Thus the activity of the pheromone depends on a final reaction which occurs in the female, using both substrate and enzyme provided by the male.     

Spermatophore web formation in a pseudoscorpion

The male pseudoscorpion Serianus sp. n. deposits spermatophores without mating, but only when females are present. It marks a path to the spermatophore with silken threads produced in an endodermal gland, which is homologous to the rectal pocket in males and females of other species and in the female of the same species.     

酱曲露尾甲飞行速度和持续时间的初步研究

本项研究应用飞行磨联接自动记录飞行的电子计算机,测定酱曲露尾甲的飞行速度和持续时间,其结果是:(1)所测定的甲虫多数只作短时间的反复飞行(1s—30min)。仅26％的雌虫和8％的雄虫飞行持续时间大于30min,最长可达6.3h.(2)雌虫飞行持续时间明显长于雄虫(P<0.05).(3)雌虫的飞行速度为1586±275m/h,雄虫的飞行速度为1195±347m/h.雌虫飞行速度比雄虫快(P<0.05).     

Infantile experience with suckling odors determines adult sexual behavior in male rats

Because infant rats learn about odors that elicit suckling, and because certain chemosensory cues that help elicit mating behavior in adults are similar to those that elicit suckling, an experiment was undertaken to assess the influence of suckling-associated odors experienced during infancy on adult sexual behavior. Rat pups lived with and suckled dams whose nipple and vaginal odors were altered with citral, a lemon scent. The rats were weaned and never exposed again, until testing, to citral or females. At about 100 days of age, the males were paired in mating tests with a normal sexually receptive female or with a sexually receptive female that had been treated perivaginally with citral immediately before testing. The males ejaculated readily when paired with citral-treated females but were slow to achieve ejaculation when paired with normal females. These findings implicate an infantile experience as a determinant of adult sexual behavior in a mammal.     

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。     

Females' choice of "good genotypes" as mates is promoted by an insect mating system

Can animal mating systems result in the choice of mates carrying genotypes that are otherwise favored by natural selection? This question is addressed by studying, in natural populations of Colias butterflies, how the phosphoglucose isomerase (PGI) enzyme genotype of males mating Colias females varies with degree of female mate discrimination. Certain PGI genotypes (as predicted from their biochemical properties) have been found previously to have an advantage in diverse fitness-related properties: flight capacity, survivorship, and overall mating success. It is shown here that males of these same genotypes have even greater advantage in remating older, more discriminating females than they do in mating previously unmated, less discriminating females. Assortative mating is not found and thus cannot explain this effect. The mating system of these insects does, at least in this case, result in active female choice of generally favorable male genotypes as mates.