黑带食蚜蝇体色变异的研究

通过对黑带食蚜蝇Episyrphus balteatus(De Geer)体色变异的研究,发现黑带食蚜蝇存在深色型和浅色型2种基本形式,体色变异具有明显的季节性,深色型个体出现在温度较低的秋季及早春,浅色型个体发生在温度较高的春夏季节;在腹部色斑方面,深色型和浅色型个体中均存在变异,可划分为8种类型,腹部色斑的变异在浅色型个体中较为丰富,腹部不同体节背板上色斑的变异程度不同;黑带食蚜蝇在体型大小方面同样存在差异,这些变异的多态性可能是食蚜蝇系统学研究中异名产生的一个重要原因。因此,食蚜蝇类群的个体体色变异在系统学研究中是一个必须特别注意的问题。     

影响麦长管蚜体色变化的主导因素

研究麦长管蚜Macrosiphum avenae(Fabricius)体色变化生态主导因素,田间红色麦长管蚜种群对不同抗蚜性寄主的反应和自然条件下,不同体色麦长管蚜的生殖力以及后代种群体色变化情况。结果显示:在实验温度范围内,麦长管蚜种群中红体色蚜虫所占比例随温度升高而增加,在28,29,30,31℃时,红体色蚜虫所占比例分别为6.66%,38.30%,70.60%和65.24%。麦长管蚜体色变化过程中,温度起到重要的作用,而与光周期和寄主营养的关系甚微。红体色麦长管蚜在不同抗蚜性的品种上其种群消长情况存在差异。田间红绿体色麦长管蚜经2代观测,平均蚜量比值分别为9.96和15.85,生殖力差异不显著。在小麦抽穗期到乳熟期红体色麦长管蚜个体比例随着田间条件的改变逐代升高(分别由第1代的17.55%和14.70%增至第2代的29.80%和42.2%)。     

棉蚜体色变化的生态遗传学研究

调查了不同寄主上棉蚜刀Aphis gossypll自受精卵孵化出的自然种群、室内混合饲养以及单个饲养蚜虫的体色变化。结果表明：不论是自然还是实验种群,是群体还是个体饲养,不论寄主、栽培条件、生育期营养相同与否,棉蚜体色在世代内稳定不变,即出生时是什么颜色保持终生不变;在世代间则随温度升高体色渐变为黄色,温度降低体色逐渐转绿。伏蚜由苗蚜而来。X²检验证实：棉蚜体色变化与营养、寄主种类、光照、光质、栽培条件等无关,仅与温度密切相关,属于同一基因型在不同环境条件下的反应规范。但在太槿上还发现有个别深黄色棉蚜,从卵孵化到迁飞体色不随温度变化,表明棉蚜体色变化中还存在遗传多态现象。胚胎学观察与染色体校型分析结果证实了上述结论与观点。     

不同地理种群和红色及绿色麦长管蚜遗传多样性分析

麦长管蚜Sitobion avenae(Fabricius)体色变异(红色和绿色)是一种常见的生物学现象,揭示其体色的转换机制对该类害虫的防控和测报具有潜在意义。本文利用微卫星标记技术,对麦长管蚜种群进行聚类分析和分子方差分析,从群体遗传学角度研究了不同地理种群和不同色型之间遗传多样性差异。研究结果表明,麦长管蚜的遗传分化主要以种群内的变异为主,种群间的变异占总变异的比例很小。此外,研究发现,红、绿体色间的遗传分化并不显著,且存在频繁的基因交流。这说明不同区域的不同体色麦长管蚜种群各自之间具有相似的遗传背景。     

棉蚜(Aphis gossypii)种群寄主分化和季节分化的微卫星引物PCR研究

通过对棉蚜群体进行室外观察、室内培养和分子遗传标记的DNA多态性分析（用3个微卫星序列为引物进行PCR）等研究,结果表明：1、冬寄主（木槿、石榴和花椒）上棉蚜种群分化较小（种群相似笥指数在0.833-0.917之间）,而冬寄主种群和夏寄主（棉花和南瓜）种群之间有较大的分化（种群相似性指数在0.589-0.756之间）。2、棉蚜自然种群是由体色不变的生物型（干母为黄色,其后代始终为黄色）和体色可变型生物型（干母为绿色,其后代有绿色和黄色两种体色）组成的混合种群。3、黄色小型蚜（伏蚜）来源于混合类群,但主要来自绿色干母多代选择分化的黄色后代,也有小部分可能来处在干母黄色的体色不变型。     

中国西北管蚜蝇属三新种记述(双翅目:食蚜蝇科)(英文)

本文记述了中国西北地区青海和甘肃两省的管蚜蝇属 Ｅｒｉｓｔａｌｉｓ Ｌａｔｒｅｉｌｌｅ三新种。平端管蚜蝇 Ｅ．（Ｅｏｓｅｒｉｓｔａｌｉｓ）ｆｌａｔｉｐａｒａｍｅｒｕｓ　ｓｐ．ｎｏｖ．,近似扁叶管蚜蝇 Ｅ．（Ｅｏｓｅｒｉｓｔａｌｉｓ） ｐｒａｔｏｒｕｍ　Ｍｅｉｇｅｎ,但第二腹节背板黄色斑不占据整个侧缘,第一和第二背板被黄色毛,阳茎侧叶大,阳茎内突不膨大可与之区别。刀茎管蚜蝇 Ｅ．（Ｅｏｓｅｒｉｓｔａｌｉｓ） ｇｌａｄｉｐａｒａｍｅｒｕｓ　ｓｐ． ｎｏｖ．与棕边管蚜蝇 Ｅ．（Ｅｏｓｅｒｉｓｔａｌｉｓ） ａｒｂｕｓｔｏｒｕｍ　（Ｌｉｎｎ）相似,但额具黄毛,侧尾叶宽大于长,上叶端部不具叶状的侧叶。本种亦与 Ｅ．（Ｅｏｓｅｒｉｓｔａｌｉｓ） ｒｕｐｉｕｍ　　Ｆａｂ．,相似,但本种体形小,阳茎侧叶基部宽．阳茎内尖细可与之区别。黑颜管蚜蝇Ｅ．（Ｅｏｓｅｒｉｓｔａｌｉｓ）ｎｉｇｒｉｃｅｐｓｓｐ． ｎｏｖ．近似灰被管蚜蝇 Ｅ．（Ｅｏｓｅｒｉｓｔａｌｉｓ） ｃｅｒｅａｌｉｓ Ｆａｂ,但腹部第三背板不具黄色斑纹,同时雄性外生殖器也与后者不同。模式标本保存于华南农业大学植物保护系昆虫标本室。     

蚜虫社会行为学概述

社会性昆虫是指在种群生命活动过程中有职能分工的一类昆虫,为大家所熟悉的例子有蜜蜂、蚂蚁等类群。以种群为单位生存的蚜虫,在有些类群中也发现了社会性昆虫所具有的某些行为特征,种群内产生了不同程度的形态变异和社会职能分工。（1）有些种类产生了真正的兵蚜,具有真正的社会性,如扁蚜科（Hormaphididae）的坚蚜亚科（Cerataphidinae）和疫绵蚜科（Pemphigidae）的瘦绵蚜亚科（hahiginae）等;（2）有些种类在形态上虽没有差异,但有些类型的个体具有与真正兵蚜相似的功能,如瘦绵蚜科和扁蚜科的部分种类,这类被称为具有“前社…     

美蓝蚜蝇属二新种记述(双翅目,蚜蝇科)

在整理美蓝蚜蝇属标本时发现2新种：缺纹美蓝蚜蝇Melangyna evittata sp.nov.,秦岭美蓝蚜蝇Melangyna qinlingensis sp.nov.,模式标本保存于陕西理工学院资源生物重点实验室,文中列出中国已知种的检索表。 缺纹美蓝蚜蝇,新种Melangyna evittata sp.nov.（图1 ～3） 雌性 未知。 ♂体长12mm;翅长10mm。 正模♂, 2004-05-05,陕西长安（太兴森林公园） ,霍科科采。 本种近似于Melangyna olsufjevi Violovitsh,但新种颜面暗棕褐色,缺黑色条纹,各足胫节棕褐色,缺亚端暗色环。新种以颜面暗棕褐色,缺暗色条纹命名,取拉丁字e（x）-（失去）和（vittatus）（具条纹的）构成新种名。 讨论新种颜面不具暗色条纹,符合亚属Meligramma特征,但后足基节后腹端角具毛簇,与该亚属特征不符;另一方面,后足基节后腹端角具黑色毛簇,符合亚属Melangyna特征,但颜面无黑色中条,与该亚属特征不符。所以其特征介于亚属Melangyna和Meligramma之间,其分类地位还有待进一步研究。 秦岭美蓝蚜蝇,新种Melangyna qinlingensis sp.nov.（图4 ～11） 雌性 未知。 ♂体长9.5mm;翅长9mm。 正模♂, 2002-07-07,陕西眉县（太白山） ,霍科科采。 本种近似于Melangyna olsufjevi Violovitsh,但新种复眼裸,颜面中条伸达触角基部,宽,小盾片被毛全黑色,足主要黑色,尾器不同。 新种以模式产地命名。     

同紫外（UV\|B）辐射时间对两种体色型麦长管蚜后代生物学特征的影响

研究紫外（UV\|B）辐射对红和绿体色型麦长管蚜的生物学特征的影响,探求紫外辐射在蚜虫种下体色分化及遗传中的作用。采用两种不同体色型的麦长管蚜\[Sitobion avenae (Fab.)\]成蚜经过30W紫外线（UV\|B）照射不同时间后,单头饲养在不同小麦品种上,分别测定了各处理F2代麦长管蚜的发育历期、体重差及相对日均体重增长率等生物学参数。结果表明：在1h紫外辐射处理后,在德国品种Astron上,红色型F2代麦长管蚜的生长发育显著加快,而绿色型无显著变化;而在中国品种小偃-22上,两种体色型F2代麦长管蚜均无显著变化;在8h紫外辐射处理后,在两种小麦品种上,两种体色型F2代麦长管蚜的生长发育均显著延缓,且绿色型延缓比例均比红色型大。说明紫外辐射对两种体色型的麦长管蚜生长发育的影响均能遗传到F2代,在Astron 小麦品种上,短时间紫外辐射能够促进红色型麦长管蚜的生长发育;在小偃22和Astron小麦品种上,长时间紫外辐射均能抑制两种体色型麦长管蚜的生长发育,且绿色型比红色型敏感。表明紫外辐射在蚜虫体色遗传中起着重要作用。     

缙云山细枝柃种群性比及空间分布

缙云山细枝柃（Eurya loquaiana）种群包含一些性别变异个体，表现出"亚雌雄异株"的特点。为分析该种群的性别格局，了解柃木属植物性别系统的进化及其适应机制，在缙云山细枝柃分布的不同生境中设置8个20 m×20 m长期观测样地，分析性比变化及其与环境、年龄结构的关系，同时设置1个20 m×60 m样地，分析植株的空间分布格局及性别间在空间上的关联。结果显示：（1）缙云山细枝柃种群总体上性别偏雌，雌雄比为1.43，性别变异株比例达14.42%。（2）各样地中雌雄比和性别变异株比例差异较大，性别变异株比例与干扰强度呈较强正相关而与海拔高度和郁闭度呈较强负相关，显示变异株的出现可能与人为干扰有一定联系；雌雄比与样地中细枝柃平均基径显著正相关，可能随着林龄的增加，雌雄比有增加的趋势。（3）细枝柃个体在空间上整体呈聚集分布，雌株、雄株及性别变异株主要呈随机分布，在部分尺度偏向于聚集分布。（4）雌株和雄株对环境异质性的响应相似，在空间分布上有一定的正相关。上述结果反应了缙云山细枝柃种群的性别格局及其生态适应机制。     

Intestinal myiasis due to Eristalis tenax: report of a new case in Spain

We describe a new case of accidental intestinal myiasis by Eristalis tenax in Spain. Only about 20 cases have been reported worldwide, two of them occurring in Spain. A 51-year-old patient with nonspecific abdominal pain and occasional diarrhoea expelled larvae in her stool. Macroscopic analysis of these larvae revealed morphology compatible with that of Eristalis tenax. The larva analysis showed its autofluorescence as parasitological feature described for the first time.     

How drone flies (Eristalis tenax L., Syrphidae,Diptera) use floral guides to locate food sources

In this study we show how inexperienced syrphid flies, Eristalis tenax, orient on artificial flowers by means of floral guides. To test the effect of floral guides such as line and ring markings on the probability and speed of the location of a potential food source, we exploited the spontaneous proboscis reaction triggered by yellow colour stimuli. We tested whether and how fast the flies, when placed on the edge of a circular dummy flower, found a small central yellow spot and touched it with the proboscis extended. The flies found the central yellow spot more often and faster if guide lines from the margin to the yellow spot were present. The effect of guide lines was dependent on the colour of the dummy flower, and independent of the colour of the guide lines, except for yellow guide lines releasing the proboscis reaction. The effect of guide lines was stronger if the yellow spot was hidden in a 2 mm deep depression and thus not as easily visible to the flies. Ring guides had a significant effect on performance only when the intensity of the central yellow spot was low.     

Spatial and temporal population differences in male density and condition in the American rubyspot, Hetaerina americana (Insecta: Calopterygidae)

Increased resource availability should favor higher animal density. It may also affect sex ratio, the male condition, and mating competition over access to females, although the direction of these variables is not straightforward to predict. Using a non-experimental approach, we carried out preliminary research using the territorial American rubyspot (Hetaerina americana) by comparing two spatially separated populations and the same population in two different seasons (each comparison with varying population densities). We first compared the sex ratio by counting males (using two categories, territorial and non-territorial) and females; relative foraging time (as an indicator of how much feeding resources each site provides); wing spot size (a sexual ornament), body size and immune melanization response (these two variables were used to assess male condition); and fighting time and contest number (to assess competition). For the seasonal comparison we used a third population in which we only compared male spot size and two indicators of condition and immune response, phenoloxidase (PO) and nitric oxide (NO) activity. The high-density population had higher values of non-territorial males (but similar sex ratio), relative foraging time, contest time and number, wing spot (but similar body size) and melanization response than the low-density population. According to season, at high density, males had higher values of wing spots, PO, and NO. Our results suggest that in a population where animals have more dietary resources, males reach a better condition despite the competition being more intense.     

Ultrastructural variation tune wing coloration of a moth Asota caricae Fabricius, 1775

Butterflies and moths develop highly ordered coloration in their wing for signal transmission. We have investigated the ultrastructural arrangement of wing coloration of a moth Asota caricae, applying light, optical polarized, and scanning electron microscopy, and spectrophotometry. The forewing of the moth is brown in color with a white spot at the center. The hindwing is golden yellow in color with many black patches in it. The ventral part of the forewing and dorsal hindwing share the similar color pattern. The ventral part of the hindwing has dull coloration in comparison to the dorsal one although the pattern remains same. The spectrometry analysis reveals various patterns of absorbance and reflectance spectra for various colors. The peak observed for various colors remain same although the intensity of peak changes. Bright colors possess highly ordered structures whereas irregular structures are found in dull colored scales. The color variation observed due to dorsal and ventral part of the wing is due to the minute difference observed in terms of ultrastructural arrangement revealed by scanning electron microscope. The color pattern of A. caricae is due to variation of microstructures present within the scale.     

Variation and seasonal changes in hoverfly species: interactions between temperature, age and genotype

Eristalis tenax L. and E. intricarius L. are two hoverflies which vary considerably in colour pattern. Whilst much of the phenotypic variation in both species is due to genetic variation at major gene loci, there are interactions with pupal temperature and with age of adult. Low pupal temperatures produce, on average, darker abdominal patterns in E. tenax , although the effect is hard to pick out in natural populations. Changes of pattern with age convert a bimodal autumn population to a unimodal post-hibernation population in the following spring. Hair colour is also made darker by cold treatment. Pupal treatments have a strong effect on hair colouration in E. intricarius. High temperatures inhibit the production of black hairs on the thorax, but not all the genotypes are equally sensitive to temperature. Seasonal fluctuations in colour pattern frequencies are detectable in E. intricarius. In three Eristalis species that have been studied so far, the interactions between genotype, age and temperature operate in quite different ways. The temperature responses may be relevant to theories of thermal melanism, although the colour pattern polymorphisms are, more obviously, examples of Batesian mimicry.     

Geographic variation in plasticity in Eristalis arbustorum

To study the evolution of phenotypic plasticity in the field, six populations of the hoverfly Eristalis arbustorum were sampled along two parallel North-South transects over a maximum daily temperature gradient. Three populations were sampled per transect. Egg batches were collected and the offspring were reared in a split family set up over three different pupal temperature regimes in the laboratory to produce population reaction norms of colour pattern, pupal development time, wing length and thorax length. Wing length and colour pattern were corrected for body size. All four characters showed plasticity in response to rearing temperature and significant differences in height, slope and shape of the reaction norms were found. Only male colour pattern showed variation in reaction norms along the North-South gradient. Most other characters showed variation in reaction norms from West to East. The two populations lying in the middle of the transects were frequendy different from the others. Within the populations, significant genotype-environment interactions were frequently found for wing length and colour pattern, indicating that genetic variation for plasticity was present. The results suggest that the populations may have evolved plastic responses to suit local environmental conditions.     

Aggressive Behavior and Courtship Rejection in Brightly and Plainly Colored Female Keeled Earless Lizards (Holbrookia propinqua)

Relationships between bright secondary sexual coloration and behavior were studied in female Holbrookia propinqua, which develop striking orange and yellow colors during the breeding season. In tethered introduction studies, brightly colored females performed aggressive courtship rejection behaviors toward conspecific males; plainly colored females were not aggressive toward males, but attempted to avoid them. Responses of females of the two color patterns toward conspecific females of both color phases were not detectably different. Experimental introductions of lizards with coloration modified by paint showed that females of both color patterns recognize any other lizard bearing the bright female colors as female, regardless of actual sex. Both the orange and yellow components were shown to contribute to sex recognition. The yellow component alone allowed accurate sex identification, but only half the females responded to males painted with only the orange female component as if they were females. Because females did not behave differently toward other females on the basis of coloration, the hypothesis that bright coloration evolved as an adaptive signal between females is rejected. The dark ventrolateral stripes of male and plainly colored females did not appear to affect intraspecific social responses by females.     

Melanin pigmentation gives rise to black spots on the wings of the silkworm Bombyx mori

Several mutants of the silkworm Bombyx mori show body color variation at the larval and adult stages. The Wild wing spot (Ws) mutant exhibits a phenotype in which the moth has a spot on the apex of the forewing. In this study, we investigated this trait to elucidate the molecular mechanism underlying the color pattern. Microscopy of the black spot of Ws mutants showed that the pigment emerges in the scales of the wing, and accumulation of the pigment becomes strong just before eclosion. We next examined the relationship between the black spot of the Ws mutant and melanin. The spectrophotometry using alkaline extracts from the black spot in the wing showed the highest absorption intensity at 405 nm, which is the absorbance wavelength of melanin. Moreover, inhibition assays for enzymes implicated in melanin synthesis using 3-iodo-l-tyrosine (a tyrosine hydroxylase inhibitor) and L-α-methyl-DOPA (a dopa decarboxylase inhibitor) revealed that treatment with each inhibitor disrupted the pigmentation of the wing of the Ws mutant. On the basis of these results, we analyzed the expression pattern of five genes involved in melanin formation, and found that the expression levels of yellow and laccase2 were increased just before pigmentation, whereas those of DDC, tan, and TH were increased when the apex of the wing turned black. These results showed that melanin pigmentation gives rise to the black spot on the wing.     

Temporal patterns of genetic and phenotypic variation in the epidemiologically important drone fly, Eristalis tenax

Eristalis tenax L. (Diptera: Syrphidae) is commonly known as the drone fly (adult) or rat‐tailed maggot (immature). Both adults and immature stages are identified as potential mechanical vectors of mycobacterial pathogens, and early‐stage maggots cause accidental myiasis. We compared four samples from Mount Fru?ka Gora, Serbia, with the aim of obtaining insights into the temporal variations and sexual dimorphism in the species. This integrative approach was based on allozyme loci, morphometric wing parameters (shape and size) and abdominal colour patterns. Consistent sexual dimorphism was observed, indicating that male specimens had lighter abdomens and smaller and narrower wings than females. The distribution of genetic diversity at polymorphic loci indicated genetic divergence among collection dates. Landmark‐based geometric morphometrics revealed, contrary to the lack of divergence in wing size, significant wing shape variation throughout the year. In addition, temporal changes in the frequencies of the abdominal patterns observed are likely to relate to the biology of the species and ecological factors in the locality. Hence, the present study expands our knowledge of the genetic diversity and phenotypic plasticity of E. tenax. The quantification of such variability represents a step towards the evaluation of the adaptive potential of this species of medical and epidemiological importance.     

Male mate searching behavior in the black chafer Holotrichia loochooana loochooana (Sawada) (Coleoptera: Scarabaeidae): response to pheromone lures of various colors and intensities

In order to understand the visual orientation mechanisms of the male black chafer Holotrichia loochooana loochooana to females, we examined male behavioral response to colored objects (lures) when female sex pheromone was present. In the field, males landed more frequently on darker lures than on lighter ones of the same color. Among lures of different colors but with the same brightness, males preferred landing on black, blue, or red ones to green or grey ones. The reflectance intensities of preferred lures were weaker than those of green and grey in the range of 540–580 nm. This range is considered to affect choice by males. When females perch on the leaf edges of the food plant to adopt a calling posture, the dominant background color is that of the leaves (i.e., green). This means that the landing target forms a silhouette (dark spot) which is prominent against a background of green leaves, providing maximum visual acuity for mating.