NOTES ON CULISETA (CULICELLA) ATRA (LEE) (DIPTERA: CULICIDAE) IN WESTERN AUSTRALIA

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Adults of Culiseta (Culicella) atra (Lee) are redescribed; the larva is described for the first time and the pupa is figured. The relationships and origin of C. atra are discussed.     

蚊幼虫体表微细结构的扫描电镜观察及分类学研究

本文用扫描电镜观察、比较了14种库蚊和6种其他蚊属的幼虫颅壳、呼吸管及尾节的体表微细结构,发现在颅壳上的微棘排列成多角形,在呼吸管和尾节上的微棘则排列成直线.这些微棘在不同区域排列有变化,但在固定的区域却很稳定,具有种内稳定性和种间差异,可以作为分类特征.本文共对20种蚊幼虫的体表微棘图式进行了描述,并以组为单位,对同组内各近似种的微棘图式进行比较和小结,提出它们的区别特征,用于鉴别近似种;根据体表图式,对库蚊个别种类的分类位置提出了不同的看法,讨论了体表微棘的起源及其分类的意义.     

LARVAL AND PUPIL BEHAVIOUR IN CULISETA LONGIAREOLATA (MACQUART, 1838) (CULICIDAE,DIPTERA)

SUMMARY

Six larval and two pupal activities could be distinguished. The larval activities are medium filter-feeding (MFF), surface filter-feeding (SFF), browsing and gnawing (BRG), swimming (SS), surface hanging (HA) and grooming (GR). The pupal activities are limited to surface hanging (HA) and swimming (SS). The percentage value of each activity from eclosion to emergence of the adults was established by means of a six-channel manual recorder. In larvae HA is the predominant activity, shows an inverse relation with all other activities, and attains peak percentage values prior to each ecdysis. BRG is the most important method of feeding, and is followed by MFF and then by SFF in order of importance. SS accounts for a low percentage value. Initially it is depth-independent in first stage larvae, but later becomes depth-dependent. In pupae the HA percentage values are high, since the pupal stage is a period of quiescence. The SS percentage values are very low and could have been escape reactions to extraneous stimuli. No circadian rhythm could be detected in any of the activities.     

白纹伊蚊卵滞育的实验观察

对两个地理品系的白纹伊蚊卵期滞育的实验观察表明:白纹伊蚊宜兴品系(约北纬31°N)不仅亲代受短光照作用后可诱导卵期发生滞育,而且卵期仍具有光照敏感性;海南岛品系(约北纬18°N)中,光期变化不能诱导卵期滞育.宜兴品系卵滞育率随亲代光期缩短而增高的现象只发生在一定范围内(约L:D=9:15到L:D=15:9).卵滞育还受卵期低温、干燥以及孵化时水中溶解氧的影响.卵进入深度滞育是多种环境因素作用的结果.     

SIGNIFICANCE OF PASSIVE MIGRATION IN EVOLUTION OF INSECTICIDE RESISTANCE IN THE MOSQUITO CULEX PIPIENS (DIPTERA: CULICIDAE)

In order to determine the combined effects of migration and gene flow on evolution of insecticide resistance in the mosquito Culex pipiens, four samples were collected in China, among which two were collected along the railway from Beijing to Guangzhou. Bioassay data showed that the resistance levels of the four populations to dichlorvos were high and to parathion moderate as compared with the susceptible strain and there was no significant difference among the four populations to the same organophosphate (OP) insecticide. Starch electrophoresis was done to identify the frequency of known overproduced esterases and to analyze genetic diversity among various populations by electrophoretic polymorphism of five presumably neutral loci. The results indicated that the gene flow between populations existed and the number of effective migrants (Nm) was related to collection geography (Nm from 1.67 to 40.07). In contrast with lower genetic differentiation between two nearby populations (between GZ and ZS, ZZ and SQ) and higher genetic differentiation between two distant populations (between GZ and ZZ), there was a significant and inconsistent difference in the distribution of resistance alleles, A2‐B2 when explained only with active migration. This divergent situation could be straightened out when considering passive migration (such as railway transport) which increased the spread of A2‐B2 along the railway, i.e., in GZ and ZZ. The resistance alleles, A2‐B2, dispersing to around areas by active migration suffered from the limitation of gene flow and the speed of invasion.     

NORTHERN RECORDS OF THE GENUS CULISETA FELT IN AUSTRALIA WITH THE DESCRIPTION OF A NEW SPECIES (DIPTERA: CULICIDAE)

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Culiseta arenivaga sp.n., described from females from Fraser Island, Queensland, provides the northernmost record of Culiseta in Australia. C. arenivaga has postspiracular setae and it is compared in text and figures with the other species known from Queensland, C. antipodea Dobrotworsky, and with the other species possessing postspiracular setae, C. littleri (Taylor), C. inconspicua (Lee), and C. atra (Lee), of which the first two are the only species known from New South Wales. Postspiracular setae are reported in C. inconspicua for the first time. C. littleri is recorded from northern New South Wales and geographical variation in this species is discussed. The unusual palmate empodium of C. antipodea females is described and figured. Relationships within the genus are considered and an austral origin for the genus is suggested.     

被动迁移在抗性进化中的作用

为了明确迁移和基因交流在杀虫剂抗性基因进化中的作用,我们从四个不同的地区采集有机磷抗性的库蚊野生种群,利用淀粉电泳鉴定了各种群中存在的已知过量产生酯酶的分布频率,并通过5个假定的中性位点的电泳多态性分析了种群间的遗传多样性。结果表明种群间的基因交流是存在的,遗传分化与地理位置存在一定关系,而抗性等位基因A2一B2的分布却与种群间的遗传分化不一致。对这种差异的解释是：被动迁移(铁路运输等)加速了抗性基因的交流,而当抗性基因以自然迁飞的方式向周围地区扩散时,却是一个相对缓慢的过程。     

伊蚊属博蚊亚属一新种及一新记录：双翅目：蚊科

本文记述采自云南省西双版纳景洪县竹穴积水伊蚊１新种,根据其成蚊特征,命名为褐盾伊蚊Ａｅｄｅｓ（Ｂｏｔｈａｅｌｌａ）ｂｒｏｗｎｓｃｕｔｕｍｕｓｓｐ．ｎｏｖ。模式标本保存于云南省疟疾防治研究所。     

STRUCTURE OF THE EGG-SHELL OF CULEX PIPIENS AND MANSONIA AFRICANA (CULICIDAE, DIPTERA)

Eggs of Culex pipiens L. are laid in rafts on the surface of still or slow moving water, whereas those of Mansonia africana (Theobold) are deposited beneath tho surface of the water on the undersides of floating leaves (Laurence & Smith 1958; Laurence 1959). The eggs of both species are surrounded by air, those of Culex pipiens are in direct contact with the external atmosphere, whereas those of Mansonia africana are partially surrounded by a bubble of air trapped between them. The anterior onds of the eggs of Mansonia africana project through the bubble of air into the surrounding water. This bubble of air is only found around living eggs and disappears if tho eggs die and shortly before they hatch. Iyengar (1935) has shown that the eggs of Ficalba minima Theo. although often deposited on the same leaf as those of Mansonioides , are laid above the water line and resemble in structure those of Culex and Coquillettidia . The structure of the egg-shell of both Culez pipiens and Mansonia africana is described and discussed.     

中国大劣按蚊复合体生物分类的研究(英文)

大劣按蚊（广义）是东南亚和我国南方的高效传疟媒介,其复合体不同成员种的传疟作用尚未清楚阐明,探索近缘种的正确鉴别为蚊虫生物分类的重要基础。本文报道对我国大劣按蚊复合体（Anophelesdiruscomplex）生物分类的研究结果,应用染色体核型、卵的扫描结构、核糖体DNA间隔2区序列及PCR鉴别检测等方法,确认该复合体A种分布于海南省,D种分布于云南省。文内并对蚊虫生物分类的发展方向及其对疟疾防治的重要性作了讨论。     

EFFECTS OF ELEVATED ATMOSPHERIC CO(2) ON WATER CHEMISTRY AND MOSQUITO (DIPTERA: CULICIDAE) GROWTH UNDER COMPETITIVE CONDITIONS IN CONTAINER HABITATS

We investigated the direct and indirect effects of elevated atmospheric CO(2) on freshwater container habitats and their larval mosquito occupants. We predicted that a doubling of atmospheric CO(2) would (1) alter the chemical properties of water in this system, (2) slow degradation of leaf litter, and (3) decrease larval growth of Aedes albopictus (Skuse) mosquitoes raised on that litter under competitive conditions. Effects of elevated CO(2) on water quality parameters were not detected, but the presence of leaf litter significantly reduced pH and dissolved oxygen relative to water-filled containers without litter. Degradation rates of oak leaf litter from plants grown under elevated CO(2) atmospheres did not differ from breakdown rates of litter from ambient CO(2) conditions. Litter from plants grown in an elevated CO(2) atmospheres did not influence mosquito population growth, but mosquito production decreased significantly with increasing larval density. Differences among mosquito density treatments influenced survivorship most strongly among male Ae. albopictus and time to emergence most strongly among females, suggesting fundamental sex-determined differences in response to competition. Results of this and other studies indicate that direct and indirect effects of doubled atmospheric CO(2) are minimal in artificial containers with freshwater.