角管库蚊在我国的发现

角管库蚊Culex(Cx.)hutchinsoni Barraud,1924属尖音库蚊类群(Cx.pipiens group)。成蚊外表与致倦库蚊Cx.(Cx.)quirquefasciatus Say,1823非常近似,仅中胸盾鳞带红棕色,侧板上部白鳞簇上下有暗斑或纵条,但两者雄蚊尾器和幼虫形态明显不同。本种雄蚊载肛突有发达的基腹突。此外,两者雌蚊的食窦甲的形态也不相同。角管库蚊幼虫的形态极为特殊(图),即呼吸管背面近末端有一角状突起。这是在蚊类幼虫极为罕见的特征。图角管库蚁Cx.hutchmsoni幼虫昆端本种库蚊于1981年8月采自云南西双版纳景洪县。幼虫孳生在电站积水(海拔900米)。角管库蚊在…     

中国库蚊属四新纪录

在整理云南蚊类标本过程中,发观库蚊属(Culex)4种新纪录,分别隶属于库状蚊亚属(Culiciomyia)1种、簇角蚊亚属(Lophoceraomyia)2种和库蚊亚属(Culex)1种。一、佛氏库蚊Culex(Cui.)fragilis Ludlow,1903检视标本:云南,勐腊。1985,Ⅷ,10—4,14,4L,采自木槽积水。鉴别特征:腹节背板全暗。雄蚊抱肢端节齿脊自亚端部伸达亚基部。幼虫头毛5,6—C从亚基部各分出5—7芒支。前胸毛1—3P均不分支。呼吸管较短,自基部向端部渐变细。呼吸管毛1—S3对,每分2—3支。本种幼虫特征突出,不难与我国已知的库状蚊相区别。本种在国外分布于泰国、菲律宾、印…     

一个链霉菌新种及其灭蚊效果

对具有灭蚊效果的链霉菌N0．7180进行了形态、培养特征和生理生化特性的研究,认为与已知的近似种都不相同,是一个新种,定名为灭蚊链霉菌(Streptomyces culicidicus Yan et al. n.sp.),它的培养物对中华按蚊、致乏库蚊、二带喙库蚊、三带喙库蚊、褐尾库蚊、骚扰阿蚊等幼虫有显著的毒杀效果。     

济南市蚊类调查报告

1.本文报告了济南市蚊虫种类,孳生地,栖息场所,幼虫发现季节,尖音库蚊淡色变种成虫、幼虫及白纹伊蚊幼虫的密度调查结果。 2.过去在济南曾有人作过蚊类的初步观察,而此次调查较为普遍。共采获蚊类标本3属11种。其中吉浦伊蚊、拟态库蚊、二带喙库蚊、褐尾库蚊4种为济南市新发现之蚊种。其中褐尾库蚊在山东省为首次发现。 3.3属蚊虫中以尖音库蚊淡色变种为最普遍,其与居民之关系亦最为密切;次之为白纹伊蚊与中华按蚊。 4.尖音库蚊淡色变种之幼虫从5月上旬开始出现,到8月中旬达最高峯,9、10月份渐少,到11月下旬绝迹。白纹伊蚊之幼虫,8月上旬密度最高,9月中旬绝迹。各种蚊幼 之密度随雨量之增减而消长。     

我国12种蚊幼虫上颚形态和鉴别特征的研究

本文对8种库蚊和按蚊、伊蚊、阿蚊及杵蚊各属代表种的4龄幼虫上颚进行扫描电镜观察.概述了上颚的外部形态,并提出了各蚊种的鉴别特征.指出幼虫上颚具有显著的种间差异,具有重要的分类学意义,讨论了上颚的结构与功能的关系.通过对上颚结构和取食方式的比较研究,从生物学角度,提出蚊科进化关系.     

库蚊属一新种(海南库蚊)的记述

库蚊属泰蚊亚属(Subgenus Thaiomyia)系 Bram 于1966年建立。至今,仅发现产于泰国山地竹林中的模式种无梳库蚊[Culex(Thaiomyia)dispectus Bram,1966]一种。 1974年6月,陆宝麟、许荣满、李蓓思等同志,曾在海南岛吊罗山树洞采得一批库蚊幼虫并育出两性成蚊,随后将标本惠赠我院,复提出建设性的鉴别意见。经研究,其雌蚊及雄尾器颇似库状蚊亚属(Subgenus Culiciomyia),但其雄须长节腹面无特殊的枪锋状鳞     

我国六种库蚊分类地位的商榷

近年来,结合《中国蚊科志》库蚊属的编写工作,查看了某些新种的模式标本,发现下列六种的分类地位有待商榷,分别讨论于下: 1.从江库蚊Culex(Moch.)chungkiangensis Chang and chang 昆虫学报17(3):347-51 从江库蚊是张培轩和张思淼同志根据贵州从江的雄蚊标本与Brug(1932)对叶片库蚊(C.foliatus)的原描述有差异而记述的新种。叶片库蚊原是根据印尼爪哇的标本作为C.castrensis的一个变种记述的。Edwards(1934)根据Jackson采自香港的标本,曾指出Brug的原插图不正确,认为其雄蚊尾器抱肢基节亚端叶有一个大叶片,     

1954年长沙市蚊虫初步调查报告

一.1954年3—10月,在长沙市初步调查蚊虫,共採得蚊种9属26种。其中有按蚊属1种、拟三翅蚊属1种、Uraunotaenia属2种、Orthopodomyia属1种、番蚊属1-种、曼蚊属1种、阿蚊属土种、蚊属3种及库蚊属15种(其中2种未定名)。所採得的9属26种蚊虫中,有树竹拟三翅蚊、Uranotaenia bimaculata、Orthopodo-myia anopheloides及罗宗番蚊4种,在湖南尚系首次报告。 二.长沙市蚊种的分佈,郊區有25种、中心區有13种。较为常见者有致乏库蚊、三 带喙库蚊、中华按蚊、白纹伊蚊貪食库蚊及骚扰阿蚊六种。 三.”长沙市各种成蚊的停歇处,主要是山陵、住宅、郊野及猪、牛栏。 四.在长沙市所发现的蚊虫中,只发现17种幼虫。各蚊种幼虫孳生地的范围是有差别的。致乏库蚊及贫食库蚊范围最广;Uranotaenia bimaculata、othopodomyiaanopheloides、黑足伊蚊的幼虫,只在树洞渍水中发现。 五.各蚊种幼虫间共生情况,已在文中讨论。 六.在调查的过程中,发现黑足伊蚊在傍晚时吸吮人血。 七.将湖南省已肢知蚊虫编为俭索表,以便有关工作人员之参考。     

中国库蚊属一新记录种

巨端库蚊Culex(Eumelanomyia)macrostytus Sirivanakarn et Ramalingan,1976 1981年7月,作者等在云南省耿马和瑞丽县森林中清凉水井内,采判幼虫20余条,并育出雌、雄成蚊备5只。该蚊为小型棕黄色蚊虫,雄蚊尾器亚端叶的形状与柬埔寨库蚊[Culex(Eum.) richi Klein,1970]相似,但后者的亚端叶后毛组最后一根为锯齿叶片状,而本种的则是有柄的械状。另外,在前毛组的形状、抱肢端节以及阳茎等均有明显差别。 园外分布:马来西亚。     

中华按蚊的幼虫绿色和幼虫褐色品系

蚊虫的幼虫体色突变品系已在淡色按蚊(Anopheles albimanus)、斯氏按蚊(An.stephensi)、致倦库蚊(Culex quinquefasciatus)和三带喙库蚊(Culex tritaeniorhychus)等许多蚊种中被分离出来。这些遗传变异品系的发现对研究蚊虫的变异性和遗传性及蚊虫和蚊媒疾病的防治有着重要的价值。在中华按蚊(Anopheles sinensis)种内至今未见关于体色遗传变异类型的报道。作者于1987—1988年在上海中华按蚊种群中,成功地分离出幼虫绿色和幼虫褐色两个品系,现报道如下。     

Scanning Electron Microscopic Studies of Epicuticular Patterns in Mosquito Larvae (Diptera, Culicidae) and Their Use as Taxonomic Characters

The development of integumental patterns on the head capsule in larval instar I-IV of Aedes (Ochlerotatus) cantons (Meigen) was studied by SEM. A comparison of several areas on the head capsule was made. Polygonal patterns of small protuberances (vesicles) were found on the entire head capsule. Arrangements vary between different areas, but within each area they are constant from the II instar throughout larval development. A comparison with five other Aedes spp. in the IV instar shows species specificity of the vesicle patterns at two areas. There the arrangement varies between rhombic and irregular pentagonal shape with sizes from 28 to 42 μm, and from round knobs to more elongated ridges (each from 2.8 μm to 11.2 μm). Treatment with different fixatives was studied. A comparison between saddle and siphon patterns of the six species is made. The possible origin of the vesicles as well as their taxonomic significance is briefly discussed. Species specific patterns exist and improve the possibility of identifying closely similar larvae. Possibly the method when further developed may serve to distinguish species groups.     

Adaptive head coloration in case-making caddis larvae

SUMMARY. 1. In daylight conditions brown trout preferably attacked head capsules with a contrasting colour pattern compared to those which were more uniformly coloured. This preference was reversed under reduced illumination. It is argued that striped head capsules are cryptic to predators at low light intensities.
2. In caddis larvae contrasting head patterns are found mainly in lentic species, whilst the heads of lotic larvae are usually more uniformly coloured. Lentic species dwell in conditions of more diffuse illumination than lotic one, and each category thus achieves high crypsis with respect to head capsule coloration.
3. Lentic molannid and phryganeid larvae often dwell at considerable depths, and these species also have the most sharply defined head patterns. These species are predatory and, besides being cryptic to larger predators, may also be cryptic to their prey.
4. Intraspecific variation in head capsule coloration in relation to habitat type is also discussed.     

Surface structure,model and mechanism of an insect integument adapted to be damaged easily

Background  

Several sawfly larvae of the Tenthredinidae (Hymenoptera) are called easy bleeders because their whole body integument, except the head capsule, disrupts very easily at a given spot, under a slight mechanical stress at this spot. The exuding haemolymph droplet acts as a feeding deterrent towards invertebrate predators. The present study aimed to describe the cuticle surface, to consider it from a mechanistic point of view, and to discuss potential consequences of the integument surface in the predator-prey relationships.     

A biomechanical analysis of prognathous and orthognathous insect head capsules: evidence for a many‐to‐one mapping of form to function

Insect head shapes are remarkably variable, but the influences of these changes on biomechanical performance are unclear. Among ‘basal’ winged insects, such as dragonflies, mayflies, earwigs and stoneflies, some of the most prominent anatomical changes are the general mouthpart orientation, eye size and the connection of the endoskeleton to the head. Here, we assess these variations as well as differing ridge and sclerite configurations using modern engineering methods including multibody dynamics modelling and finite element analysis in order to quantify and compare the influence of anatomical changes on strain in particular head regions and the whole head. We show that a range of peculiar structures such as the genal/subgenal, epistomal and circumocular areas are consistently highly loaded in all species, despite drastically differing morphologies in species with forward‐projecting (prognathous) and downward‐projecting (orthognathous) mouthparts. Sensitivity analyses show that the presence of eyes has a negligible influence on head capsule strain if a circumocular ridge is present. In contrast, the connection of the dorsal endoskeletal arms to the head capsule especially affects overall head loading in species with downward‐projecting mouthparts. Analysis of the relative strains between species for each head region reveals that concerted changes in head substructures such as the subgenal area, the endoskeleton and the epistomal area lead to a consistent relative loading for the whole head capsule and vulnerable structures such as the eyes. It appears that biting‐chewing loads are managed by a system of strengthening ridges on the head capsule irrespective of the general mouthpart and head orientation. Concerted changes in ridge and endoskeleton configuration might allow for more radical anatomical changes such as the general mouthpart orientation, which could be an explanation for the variability of this trait among insects. In an evolutionary context, many‐to‐one mapping of strain patterns onto a relatively similar overall head loading indeed could have fostered the dynamic diversification processes seen in insects.     

Investigation of the within- and between-sample colour pattern differentiation in Hydropsyche contubernalis (Trichoptera)

The caddisfly Hydropsyche contubernalis (Trichoptera; Hydropsychidae) occurs in rivers and large streams throughout Europe. The aquatic larvae of this species are highly variable in their head capsule colour patterns. This paper describes the differentiation of such a pattern within and between 13 samples from three different West European river basins. The main aim is to investigate whether differences in colour pattern exist between river basins. Because the head capsule colour patterns of H. contubernalis do not have clear detectable morphs, an image analysis technique is presented to quantify the pattern in the form of mean colour curves expressed as grey levels. These curves are described by mathematical spline functions, and the differences between these functions, which formalize the original data set of colour curves, are analysed by multivariate Between-Group Principal Component Analysis. Our results show that distinct head capsule colour patterns occur in the Loire and Rhône, individuals of the Rhône being darker than individuals of the Loire. However these results also suggest that important differences in such a colour pattern can be detected at smaller scales: along the whole length of the Loire; within a 10km stretch of the Doubs, and also within a single site on the Loire (Amboise). Temporal differences at the same site between different H. contubernalis generations were also recorded. The mechanisms responsible for such differentiation patterns are discussed but still remain unclear. The overall statistical procedure detailed in this paper could potentially be used in numerous other fields of evolutionary biology.     

Culex mosquitoes in temporary urban rain pools: seasonal dynamics and relation to environmental variables.

The study was conducted in a park of Buenos Aires City, where a total of 89 rain pools were sampled weekly for mosquito immature stages over a one-year period. The aim of the present paper was to investigate the seasonal dynamics of three Culex species breeding in temporary rain pools and to analyze the relationships of the presence of these species to pool dimensions, pool age, vegetation, and insolation degree. The three species showed differences in their seasonal patterns, Culex dolosus being present during the whole year, Culex pipiens mainly in the summer season, and Culex maxi almost exclusively during the fall. The variable explaining most of the variation among sampling dates in species composition was weekly mean temperature. A significant positive association was detected among mosquito species, as they were recorded together more frequently than expected by chance. The statistical analyses performed revealed significant positive relationships of all three mosquito species to increasing surface area, whereas no relationship to insolation degree was detected in the studied pools. Culex pipiens and Culex dolosus showed positive relationships to increasing vegetation cover, whereas the presence of Culex dolosus was also related to pool age.     

Ultrastructural Effects of a Non-Steroidal Ecdysone Agonist,RH-5992, on the Sixth Instar Larva of the Spruce Budworm,Choristoneura fumiferana

Force feeding of RH-5992 (Tebufenozide), a non-steroidal ecdysone agonist to newly moulted sixth instar larvae of the spruce budworm, Choristoneura fumiferana, (Lepidoptera: Tortricidae) initiates a precocious, incomplete moult. Within 6h post treatment (pt) the larva stops feeding and remains quiescent. Around 12hpt, the head capsule slips partially revealing an untanned new head capsule that appears wrinkled and poorly formed. By 24hrpt, the head capsule slippage is pronounced and there is a mid-dorsal split of the old cuticle in the thoracic region but there is no ecdysis. The larva remains moribund in this state and ultimately dies of starvation and desiccation. The temporal sequence of the external and internal changes of the integument were studied using both scanning and transmission electron microscopy. Within 3hpt, there is hypertrophy of the Golgi complex indicating synthetic activity and soon after, large, putative ecdysial droplets are seen. Within 24h, a new cuticle that lacks the endocuticular lamellae is formed. The formation of the various cuticular components, the degradation of the old cuticle and changes in the organelles of the epidermal cells of the mesothoracic tergite are described. The difference between the natural moult and the one induced by RH-5992 are explained on the basis of molecular events that take place during the moulting cycle. The persistence of this ecdysone agonist in the tissues permits the expression of all the genes that are up-regulated by the presence of the natural hormone but those that are turned on in the absence of the hormone are not expressed.     

Convergent evolution of sexual shape dimorphism in Diptera

Several patterns of sexual shape dimorphism, such as male body elongation, eye stalks, or extensions of the exoskeleton, have evolved repeatedly in the true flies (Diptera). Although these dimorphisms may have evolved in response to sexual selection on male body shape, conserved genetic factors may have contributed to this convergent evolution, resulting in stronger phenotypic convergence than might be expected from functional requirements alone. I compared phenotypic variation in body shape in two distantly related species exhibiting sexually dimorphic body elongation: Prochyliza xanthostoma (Piophilidae) and Telostylinus angusticollis (Neriidae). Although sexual selection appears to act differently on male body shape in these species, they exhibited strikingly similar patterns of sexual dimorphism. Likewise, patterns of within-sex shape variation were similar in the two species, particularly in males: relative elongation of the male head capsule, antenna, and legs was associated with reduced head capsule width and wing length, but was nearly independent of variation in thorax length. However, the two species presented contrasting patterns of static allometry: male sexual traits exhibited elevated allometric slopes in T. angusticollis, but not in P. xanthostoma. These results suggest that a shared pattern of covariation among traits may have channeled the evolution of sexually dimorphic body elongation in these species. Nonetheless, static allometries may have been shaped by species-specific selection pressures or genetic architectures.     

An ultrastructural study of the larval integument of the midge,Chironomus riparius meigen (Diptera: Chironomidae)

Summary The larval integument of the midge, Chironomus riparius Mg., is unusually thin although it conforms with the normal insect pattern. The cuticle of the post-cephalic segments is about 3 m thick and overlies an epidermis which has an irregular basal plasma membrane resulting in spaces occurring between it and the basement membrane. The ventral tubuli have a similar epidermis but the cuticle is somewhat thinner. The anal papillae have the thinnest cuticular covering with a uniquely folded epicuticle of variable thickness, and their epidermis has the characteristics of a transporting epithelium. No evidence of pore canals could be found in the cuticle of any part except the head capsule which has a remarkably smooth epicuticle and a distinct layer which may represent the exocuticle. There are no spaces between the basement membrane and basal plasma membrane of the epidermis in the head. Ultrastructural evidence would suggest that gaseous exchange can occur across most of the post-cephalic integument.The author is indebted to Mrs. L. Rolph and Mr. R.L. Jones for their technical assistance