中国多斑按蚊类群小记（双翅目：蚊科）

多斑按蚊Anopheles maculatus(Theobald)(s.l.)广布于我国北纬34°以南地区,过去都视作单一蚊种。根据近年的研究,它实际是包含若干亲缘种的种团。为此,我们检视了本单位收藏的标名为多斑按蚊的标本,发现有本种团的以下5种,多斑按蚊(s.s.)伪威氏按蚊pseudowillmori、塞沃按蚊sawadwonaporni、达罗毗按蚊dravidicus和威氏按蚊willmori,后两种为我国的新记录。 本文附有上述5种雌蚊的检索表。     

Effects of salinity on the larvae of some Afrotropical anopheline mosquitoes

ABSTRACT. Laboratory experiments showed that the larvae of some freshwater-breeding Afrotropical anopheline species exhibit various degrees of tolerance to 25% sea-water. At 24^oC, survival rates from egg to fourth instar larva were significantly less in salt-water than in freshwater for four species: 39.5% versus 55.4% for Anopheles tenebrosus Dönitz, 31.9% versus 86.2% for An. mousinhoi De Meillon & Pereira, 3.5% versus 67.9% for An. pharoensis Theobald and 3.9% versus 41.9% for An. quadriannulatus (Theobald). Conversely, An. merus Dönitz showed a significantly better survival rate of 46.4% in 25% sea-water compared with 15.5% in freshwater. Simulated winter conditions did not significantly change these differential survival rates of An. merus. Effects of salinity on the anal papillae of third instar larvae are discussed.     

Engorgement response of anopheline mosquitoes to blood fractions and artificial solutions

ABSTRACT. Anopheles stephensi Liston, Anopheles freeborni Aitken, Anopheles gambiae Giles and Anopheles dirus (Peyton & Harrison) fed equally well on whole blood, red blood cells, platelet-rich plasma and platelet-poor plasma. Similar feeding ability on 0.15 M NaCl containing 10^-2 M NaHCO₃ was shown by the first three species, but An. dirus required an addition of albumin. The need for ATP as a phagostimulant could not be demonstrated in any of these species.     

DNA probes for species identification of mosquitoes in the Anopheles gambiae complex

Abstract. Identification of species within the Anopheles gambiae Giles species complex is essential for the correct evaluation of malaria vector ecology studies and control programmes. The development of DNA probes to distinguish species of the An.gambiae complex is described. Genomic libraries were prepared for four members of the An.gambiae complex. These were screened using radiolabeled DNA from different species of An. gambiae sensu lato and a number of clones selected on the basis of their species specificity. These clones could be divided into two groups, each containing homologous sequences. Sequences homologous to group 1 inserts are highly reiterated in the genomes of Anopheles arabiensis Patton and Anopheles merus Dönitz, present in low copy number in Anopheles melas Theobald, but were not detected in Anopheles gambiae sensu stricto. Studies on the organization of this sequence in the genome of An.arabiensis show that homologous sequences are male specific and interspersed within the chromatin. Sequences homologous to group 2 inserts are highly repeated in the genomes of An.merus and An.melas, but present in low copy number in An.gambiae s.s. and An.arabiensis. Group 2 homologous sequences are not sex-specific in the species tested and appear to be tandemly repeated. When used as hybridization probes, these sequences provide a sensitive means for the identification of species within the Anopheles gambiae complex.     

越冬中华按蚊生理生态的研究

中华按蚊 Anopheles sinensis以成蚊越冬.在上海、无锡从11月至3月上旬当气温超过10℃时,于畜棚可诱捕到新饱血蚊.卵巢发育观察表明,71.5%为发育蚊,吸血蚊生殖营养协调.另外还捕到个别经产蚊(1.3%).采自户外草堆等处的越冬蚊人工喂血与卵巢发育观察表明,64%为滞育蚊,35%为静止的发育蚊.滞育蚊出现于11月份,持续2个月,到2月底及3月上旬滞育开始解除.本研究结果表明,中华按蚊在上海、无锡是以深滞育(3%)、浅滞育(41%)与静止(56%)的生理状态越冬.     

Anopheles (Anopheles) neomaculipalpus: a new malaria vector in the Amazon basin?

Abstract. Anopheles (Anopheles) neomaculipalpus Curry (Diptera: Culicidae) collected by human landing catches and light traps in southern Venezuela were assayed by enzyme-linked immunosorbent assay (ELISA) for detection of Plasmodium circumsporozoite (CS) protein. A total of 356 An. neomaculipalpus were collected, of which three (0.84%) were positive for P. vivax, two for the variant 247 and one for the variant 210. The overall sporozoite rate in An. neomaculipalpus was similar to that for the principal vector An. (Nyssorhynchus) darlingi Root (0.82%) and higher than in An. (Nys.) marajoara Galvão & Damasceno (0.27%). This is the first report of An. neomaculipalpus naturally infected with Plasmodium parasites in Venezuela.     

Diversity of Anopheles species and trophic behavior of putative malaria vectors in two malaria endemic areas of northwestern Thailand

We determined the species diversity, blood‐feeding behavior, and host preference of Anopheles mosquitoes in two malaria endemic areas of Tak (Mae Sot District) and Mae Hong Son (Sop Moei District) Provinces, located along the Thai border with Myanmar, during a consecutive two‐year period. Anopheline mosquitoes were collected using indoor and outdoor human‐landing captures and outdoor cow‐baited collections. Mosquitoes were initially identified using morphological characters, followed by the appropriate multiplex AS‐PCR assay for the identification of sibling species within Anopheles (Cellia) complexes and groups present. Real‐time PCR was performed for parasite‐specific detection in mosquitoes (Plasmodium spp. and Wuchereria bancrofti). A total of 7,129 Anopheles females were captured, 3,939 from Mae Sot and 3,190 from Sop Moei, with 58.6% and 37% of all anophelines identified as An. minimus, respectively. All three malaria vector complexes were detected in both areas. One species within the Minimus Complex (An. minimus) was present along with two related species in the Funestus Group, (An. aconitus, An. varuna), two species within the Dirus Complex (An. dirus, An. baimaii), and four species within the Maculatus Group (An. maculatus, An. sawadwongporni, An. pseudowillmori, and An. dravidicus). The trophic behavior of An. minimus, An. dirus, An. baimaii, An. maculatus, and An. sawadwongporni are described herein. The highest An. minimus densities were detected from February through April of both years. One specimen of An. minimus from Mae Sot was found positive for Plasmodium vivax.     

Larval salinity tolerance of two members of the Anopheles funestus group

The Anopheles funestus group (Diptera: Culicidae) is one of the main species groups involved in malaria transmission in the Afrotropical regions. Basic research into this group has been limited because its members are eurygamic (they tend not to mate in confined spaces), which makes laboratory colonization difficult. Currently, only a few An. funestus Giles colonies are available and no colonies of other members of the group have been established. As information on the larval biology of members of the An. funestus group is limited, the present study aims to determine the effects of different salt concentrations on survival rates of the aquatic stages of two members of the An. funestus group, Anopheles funestus and Anopheles rivulorum Leeson. There were statistically significant negative trends in hatch rate and larval survival rate in An. funestus with increasing salt concentrations, with no larvae surviving to pupae at concentrations that included > 15% seawater. Anopheles rivulorum, by contrast, showed no significant trends in hatch rate or larval survival with increasing salt concentrations. This is the first report on salinity tolerance in An. rivulorum. A basic understanding of these variations in salinity tolerance provides vital information on the biology, ecology and colony rearing of members of the An. funestus group.     

韩国赫坎按蚊复合体3成员种核糖体DNA内转录间隔2区的比较(英文)

本文对韩国中华按蚊、雷氏按蚊和八代按蚊核糖体DNA (rDNA)内转录间隔 2区 (ITS2 )序列进行了比较研究。用PCR扩增的rDNA ITS2片段直接测序 ,每种蚊测定 3个个体 ,结果显示 :韩国中华按蚊、雷氏按蚊和八代按蚊的rDNA ITS2序列长度分别为 4 6 8bp、 4 51bp和 4 53bp ,GC含量分别为 4 4 .87%、 4 6 .2 %和 4 5.7% ,3种按蚊序列差异范围为 12 .16 %— 30 .74 %。研究表明 ,rDNA ITS2序列差异可用于韩国中华按蚊、雷氏按蚊和八代按蚊的分子鉴别。     

Insecticide susceptibility of Anopheles coluzzii and Anopheles gambiae mosquitoes in Ibadan,Southwest Nigeria

The emergence of insecticide resistance in Anopheles (Diptera: Culicidae) mosquitoes has great implications for malaria control in Nigeria. This study aimed to determine the dynamics of insecticide susceptibility levels and the frequency of knock‐down resistance (kdr) mutations (L1014F) in wild Anopheles coluzzii Coetzee & Wilkerson sp. n. and Anopheles gambiae Giles from the Ojoo and Bodija areas of Ibadan, in southwest Nigeria. Insecticide susceptibility to pyrethroids, organophosphates, carbamates and organochlorines was assessed using World Health Organization (WHO) bioassays. A subset of the mosquitoes exposed to pyrethroids and DDT was used for species and molecular form identification; kdr genotyping was determined using the TaqMan real‐time polymerase chain reaction assay. The mosquitoes were resistant to pyrethroids and DDT but completely susceptible to organophosphates and carbamates. Bodija samples (n = 186) consisted of An. gambiae (91.4%) and An. coluzzii (8.1%) and included one An. coluzzii/An. gambiae hybrid specimen. All mosquitoes screened in Ojoo (n = 26) were An. gambiae. The 1014F kdr mutation was detected at frequencies of 24.5 and 5.8% in Bodija and Ojoo, respectively. No correlation was observed between kdr genotypes and resistance phenotypes. The results indicate that metabolic resistance probably plays an important role in the development of resistance and highlight the need to implement insecticide resistance management strategies.     

Observations on the Anopheles gambiae complex in the Senegal River Basin, West Africa

1. Three sibling species of mosquitoes of the Anopheles gambiae complex are found in the Senegal River Basin: An. melas Theobald, An. gambiae Giles and An. arabiensis Patton. 2. An. melas is restricted to the river delta and environs where saltwater breeding places are present. 3. An. gambiae and An. arabiensis are sympatric in the study area; An. arabiensis predominates in coastal zones where it breeds also during the dry season; An. gambiae predominates in inland areas where breeding is mostly restricted to the rainy season (July-September). 4. An. arabiensis is chromosomally polymorphic all over the study area, with much variation of inversion frequencies, particularly for the 2Ra arrangement. 5. An. gambiae is characterized by a very high frequency of the 2Rb-2La inversion arrangement which is typical of the Savanna chromosomal form.     

Geographical and developmental components of adult size of neotropical Anopheles (Nyssorhynchus)

Abstract.

• 1 Wing lengths were used as indicators of size of host-seeking females of four species of malaria vectors captured at human or animal baits in South America.
• 2 Geographic variation in size was observed among populations of Anopheles aquasalis and A.nuneztovari, but not A.albitarsis or A.triannulatus.
• 3 The frequency distributions of wing lengths in large collections of host-seeking A.aquasalis and A.albitarsis exhibited significant negative skewness, suggesting that the preponderance of biting females approached maximum size.
• 4 Relationships between season or physiological state (parity, blood, eggs) and the sizes of host-seeking females were not generally significant.
• 5 When A.aquasalis, A.albitarsis and A.nuneztovari were reared separately at two larval densities, initial density, but not species, significantly affected wing lengths. Significant species × density interactions may be attributable to species-specific responses to density.
• 6 Compared to other mosquitoes, the sizes of host-seeking Anopheles (Nyssorhynchus) varied little within natural populations. Laboratory studies on the fitness of unnaturally small malaria vectors may bear little relevance to the fitness of host-seeking Anopheles in nature.

     

Efficacy of permethrin-impregnated curtains for malaria vector control

Preliminary results obtained by the use of permethrin-impregnated curtains against the Afrotropical malaria vectors Anopheles gambiae Giles s.l. and An.funestus Giles are reported and discussed. Field trials were carried out in villages near Ouagadougou, Burkina Faso. Houses were provided with curtains made from 100% cotton netting, impregnated with permethrin at the dose of 1 g a.i./m2, to cover the doorway, the window(s) and the space under the eaves. Entomological data collected during the period 1985-86 showed residual permethrin activity for about a year, and almost complete prevention of indoor-resting mosquitoes. Increased exit-rate and mortality-rate of house-entering malaria vectors were also obtained. Utilization of this malaria vector control method in primary health care programmes is advocated.     

Studies of house-entering habits of mosquitoes in The Gambia, West Africa: experiments with prefabricated huts with varied wall apertures

The house-entering behaviour of nocturnal mosquitoes was studied in The Gambia. Mosquitoes were captured as they attacked man in the open and in experimental huts which comprised 1.8 m cube frames with corrugated iron roofs and plywood walls of various heights. Catches of all species were similar in the open and in a roofed, but unwalled, hut frame. The mosquitoes taken in catches in unwalled huts and others with wall heights of 0.6, 1.2 and 1.7 m (giving an 8 cm eaves-level entry slit) fell into two categories. The first group, which included the endophilic species Anopheles gambiae Giles s.l., An. melas Theobald and Mansonia spp. were only slightly affected by increasing wall height, but the second group, including the exophilic mosquitoes Aedes spp., An. pharoensis Theobald, Cx poicilipes (Theobald) and Cx thalassius Theobald showed a very marked progressive exclusion. In comparisons of catches in two huts with 8 cm entry slits at eaves or ground level, large numbers of An. pharoensis found access through the ground level entry but not at eaves level. No consistent difference could be demonstrated for other species. It is concluded that the house-entering behaviour which distinguishes endophagic mosquito species includes at least two distinct responses: flight upwards to eaves level and the passage from outside to indoors. It is also suggested that house entry as a component in host-seeking behaviour and indoor resting are distinct, but not necessarily exclusive, behavioural traits.     

Behavioral responses of Anopheles species (Culicidae: Diptera) with varying surface exposure to pyrethroid‐treated netting in an excito‐repellency test system

Indoor Residual Spray (IRS) with insecticides has been a procedure used for decades to protect humans from biting mosquitoes and potential vectors of pathogens. The objective of this study was to determine the responses of three wild‐caught species of malaria vectors exposed to pyrethroids of three different surface coverage percents using an excito‐repellency test box. Each species was exposed to three insecticide‐treated surfaces at varying exposure levels (full coverage, 50%, and 25% of the maximum allowable by the test system) to a single standard field dose of either lambda‐cyhalothrin or alpha‐cypermethrin. Larger numbers of mosquitoes escaped the treated chambers in the direct contact test compared to the spatial repellent chambers in all three different treated surface exposures. No significant differences in the percent of escaped mosquitoes were detected in the 50% and full coverage surface coverage exposures, whereas the 25% coverage produced significantly lower avoidance responses for both compounds. This study found that varying levels of surface exposure with synthetic pyrethroids can impact the behavioral avoidance responses of Anopheles; however, it may also be possible to reduce the amount of coverage to achieve similar avoidance actions. This information may assist policy makers in designing more cost effective strategies involving residual insecticides to control mosquito vectors.     

Spatio‐temporal variations of Anopheles coluzzii and An. gambiae and their Plasmodium infectivity rates in Lobito,Angola

From 2003 to 2007, entomological surveys were conducted in Lobito town (Benguela Province, Angola) to determine which Anopheles species were present and to identify the vectors responsible for malaria transmission in areas where workers of the Sonamet Company live. Two types of surveys were conducted: (1) time and space surveys in the low and upper parts of Lobito during the rainy and dry periods; (2) a two‐year longitudinal study in Sonamet workers' houses provided with long‐lasting insecticide‐treated nets (LLIN), “PermaNet,” along with the neighboring community. Both species, An. coluzzii (M molecular form) and An. gambiae (S molecular form), were collected. Anopheles coluzzii was predominant during the dry season in the low part of Lobito where larvae develop in natural ponds and temporary pools. However, during the rainy season, An. gambiae was found in higher proportions in the upper part of the town where larvae were collected in domestic water tanks built near houses. Anopheles melas and An. listeri were captured in higher numbers during the dry season and in the low part of Lobito where larvae develop in stagnant brackish water pools. The infectivity rates of An. gambiae s.l. varied from 0.90% to 3.41%.     

Malaria in urban and rural Kinshasa: the entomological input

Abstract. Mosquitoes were collected on human bait over a 16-month period (September 1988 to December 1989) in an urban and a rural area of Kinshasa, Zaïre. P.falciparum malaria sporozoite rates were determined by ELISA. In the urban area Culex quinquefasciatus accounts for 96% of the 121 bites/ person/night (b/p/n). The only anopheline is Anopheles gambiae, sensu stricto, with an average of 5.1 b/p/n and a sporozoite rate of 1.86%. The entomological inoculation rate (EIR) averages 0.08 infective b/p/n. Malaria transmission is almost interrupted at the end of the dry season. In the rural area mosquito nuisance is small (20b/p/n), almost entirely due to six species of Anopheles including four vectors of malaria: An.gambiae (13.3 b/p/n), An.funestus (2.4b/p/n), An.nili (0.4b/p/n) and An.brunnipes (0.7b/p/n) with mean sporozoite rates of 7.85%, 6.60%, 6.63% and 0.53% respectively. An.paludis (0.4b/p/n) and An.hancocki (0.2b/p/n) were not found infective. Malaria transmission is intense and perennial: the overall EIR varies monthly between 0.60 and 3.29 infective b/p/n. The specific contributions of An.gambiae, An.funestus and An.nili average 1.07, 0.14 and 0.03 infective b/p/n respectively. Malaria transmission peaks during the rainy season in both study areas. The daily mean survival rates for An.gambiae were 0.91 and 0.78 in the rural and urban area, respectively. All An.gambiae examined belonged to the forest cytotype (Coluzzi et al., 1979). Through its effect on the sporozoite rate, the higher vector survival rate in the rural environment appears to be the major determinant of the greater malaria transmission rate in the rural area as compared to urban Kinshasa.     

Field trial of the effectiveness of indoor-spraying with pirimiphos-methyl emulsion for malaria control in a tribal area of Phulbani district, Orissa State, India

A field trial of malaria vector control was conducted in Phulbani district, Orissa, during 1984 and 1985. Indoor-spraying of pirimiphos-methyl emulsion formulation was undertaken at an application rate of 2 g/m2 in two sections (population 14,692) of Nuagaon Primary Health Centre. Houses in two adjacent sections (population 21,450) were sprayed with DDT a water dispersible powder (wdp) formulation at 1 g/m2 for comparison purposes. Operational problems in this area come from the tendency of tribal people to re-plaster over wdp applications. Pre-spray malariological indices in the trial area were 38% slide positivity rate, 37% slide falciparum rate and 12.1% annual parasite incidence. Densities of Anopheles annularis Van der Wulp, An. culicifacies Giles, An. fluviatilis Theobald and other potential malaria vectors were reduced in the pirimiphos-methyl trial area 2-35-fold more than in the area sprayed with DDT. Malariological indices were reduced by 65-68% in the pirimiphos-methyl sprayed area compared with only 26-35% reduction in the DDT sprayed area. Spraymen and villagers experienced no adverse side-effects from residual house-spraying with pirimiphos-methyl emulsion and it is concluded that this organophosphate product has advantages for malaria vector control, especially in operationally difficult situations.     

Biting activity and host preference of the malaria vectors Anopheles maculatus and Anopheles sawadwongporni (Diptera: Culicidae) in Thailand

Adult mosquitoes in the Anopheles maculatus group were surveyed from different regions of Thailand and five different species were morphologically identified, including Anopheles maculatus, Anopheles sawadwongporni, Anopheles notanandai, Anopheles dravidicus, and Anopheles willmori. Blood‐feeding activity and host preference of two species, Anopheles maculatus and Anopheles sawadwongporni, were observed during a one‐year period at Pu Teuy Village, Sai Yok District, Kanchanaburi Province, west‐central Thailand. Both species were more prevalent during the wetter period of the year and each had a greater predilection to feed on cattle than humans. Primary feeding activity occurred between 20:00‐23:00 and a smaller peak at 01:00‐03:00. Findings are discussed relative to the importance of these two vectors for malaria transmission in Pu Teuy.     

Abundance, biting behaviour and parous rate of anopheline mosquito species in relation to malaria incidence in gold-mining areas of southern Venezuela

Abstract A longitudinal entomological and epidemiological study was conducted in five localities of southern Venezuela between January 1999 and April 2000 to determine the abundance, biting behaviour and parity of anopheline mosquitoes (Diptera: Culicidae) in relation to climate variables and malaria incidence. A total of 3685 female anopheline mosquitoes, representing six species, were collected. The most abundant species were Anopheles marajoara Galvão & Damasceno (60.7%) and Anopheles darlingi Root (35.1%), which together represented 95.8% of the total anophelines collected. Abundance and species distribution varied by locality. Malaria prevalence varied from 12.5 to 21.4 cases per 1000 population. Transmission occurred throughout the year; the annual parasite index (API) for the study period was 813.0 cases per 1000 population, with a range of 71.6?2492 per 1000 population, depending on locality. Plasmodium vivax (Grassi & Feletti) (Coccidia: Plasmodiidae) accounted for 78.6% of cases, Plasmodium falciparum (Welch) for 21.4% and mixed infections (Pv+Pf) for < 0.1%. Anopheles marajoara and An. darlingi were more abundant during the rainy season (April–September). There was no significant correlation (P > 0.05) between mosquito abundance and rainfall. Correlations between malaria incidence by parasite species and mosquito abundance were not significant (P > 0.05). Monthly parous rates were similar for An. marajoara and An. darlingi throughout the year, with two peaks that coincided with the dry?rainy transition period and the period of less rain. Peaks in the incidence of malaria cases were observed 1 month after major peaks in biting rates of parous anophelines. Anopheles darlingi engages in biting activity throughout the night, with two minor peaks at 23.00–00.00 hours and 03.00–04.00 hours. Anopheles marajoara has a different pattern, with a biting peak at 19.00?21.00 hours and 76.6% of biting occurring before midnight. Although both vectors bite indoors and outdoors, they showed a highly significant (P < 0.01) degree of exophagic behaviour. The present study constitutes the first effort to characterize the bionomics of anophelines in malaria endemic foci in different ecological situations in relation to malaria transmission in southern Venezuela and to provide relevant information to be considered when planning and implementing vector control programmes.