Blackfly Fauna Research Articles

ブユの生態に関する研究 (5) : 千葉県のブユ相

A fauna and distribution of blackflies (Simuliidae : Diptera) in Chiba Prefecture were investigated by collection of larvae and pupae. A total of 2,855 larvae and 652 pupae was collected from 54 sites. One genus, including eleven species were found, of which Shimulium subcostatum, S. mie, S. konoi, S. takahasii, S. japonicum and S. suzukii were newly recorded. The predominant species was S. bidentatum, followed by S. japonicum, S. uchidai, S. aokii, S. takahasii and S. nikkoense.

Karyotypical features and taxonomic position of the genus Eusimulium (Diptera: Simuliidae)

The world fauna of black flies contains more than 1000 species classified into 59 genera (Rubzov, 1974). Four hundred species referable to 25 genera are found in the Soviet Union. These are small and morphologically uniform flies, therefore the species diagnostics is very difficult. Valuable information may be derived from the analysis of polytene chromosomes. We have applied this method to the family Simuliidae. During the last few years we have analyzed the chromosomes of about 100 species from different genera, collected in various geographic regions of the USSR, using the aceto-orcein squash technique. Intraspecific, intrageneric and intergeneric analysis were carried out (Chubareva, 1974, 1977a, b, c, d, 1978a, b) in which the main chomosome markers, banding sequences and types of rearrangements were compared. From the available data one can conclude that the Simuliidae is karyologically a very homogeneous group. The majority of species studied have 2n = 6; the only species found so far with 2n = 4 are Cnephia lapponica (Petrova, 1972) and members of the genus Eusimulium ('aureum group', Dunbar, 1958; Simonenko, 1966; Chubareva & Shcherbakov, 1963). This pattern shows that the chromosome number alone is insufficient to characterize the taxonomic affiliations and that much attention in karyological analysis should be given to structural peculiarities of polytene chromosomes. The diploid number of 4, characterizing all Eusimulium species, separates this from other genera of the family, and has attracted special attention of cytogeneticists (Dunbar, 1968, 1959; Chubareva & Shcherbakov, 1963; Simonenko, 1966). It should be mentioned that at this stage species of the genus Eusimulium are morphologically distinguishable neither in the adult nor in the larval stage, hence the karyological analysis greatly facilitates taxonomic diagnostics. This paper deals with karyotypic characteristics of the species in the genus Eusimulium Roub., and the position of the latter in the family. FormedyEusimulium was considered a large genus consisting of 5 species groups (montiun~ alpinum, latipes, angustitarse and aureum). Recently, due to research of Crosskey (1969) and Rubzov (1974), it was reclassified into four distinct genera, the old generic name being retained for the species of the aureum group in the fauna of the USSR. The six genera have been placed in the tribe Eusimuliini by Rubzov (1974). All of these have been studied karyologically by us (Table i).

The Influence of a Lake on the Distribution of Blackfly Species (Diptera: Simuliidae) along a River

Three species, Metacnephia tredecimatum Edw., Schoenbaueria annulitarsis Zett. and Simulium truncatum Lundstr. dominate the blackfly fauna of Tjulan at its outlet from lake Stora Tjultrask, Swedish Lapland. Benthic density of the larval assemblage decreases during July and there are changes in composition of the species both with time, and with distance along the river from the lake. Thus Sch. annulitarsis dominates the immediate lake-outlet, and extends into the lake, while M. tredecimatum and S. truncatum dominate in the region of the river where larvae are most numerous. Because M. tredecimatum is temporally well-separated in development from S. truncatum it contributes a decreasing percentage of the total blackfly fauna with time while the latter thus contributes a higher percentage. For all species pupation is later at increasing distance from the lake. The assemblage of species extends for c. 500 m after which typical river species begin to appear. It is proposed that the lake-outlet species withstand high population densities so that they can ingest particulate material egested by larvae upstream, this being considered to be an optimal food source.

Four New Species of Prosimulium (Diptera: Simuliidae) from Western United States

During recent years intensive studies have been carried out on the black-fly fauna of Utah and of Wyoming by the senior author and junior author respectively. As a result of these investigations a number of new black-fly specieswere collected, four of which are described below.The following descriptions and measurements were made from alcohol-preserved specimens, hut where available, pinned, dried specimens were also used in preparation of the descriptions. Most of the drawings were made from slide mounts with the aid of a Ray-O-Scope microprojection apparatus; the others were made from cleared spechens retained in glycerin and were drawn with the aid of a squared-grid ocular in a stereoscopic microscope.

Observations on Mating, Feeding, and Oviposition of Some Utah Species of Black Flies (Diptera: Simuliidae)

The literature contains numerous references to observations and investigations on various aspects of the biology of many species of black flies. During recent studies on the blackfly fauna of Utah, observations were made on mating, feeding, and oviposition of several species of black flies for which such data are fragmentary or completely lacking.

三重県におけるブユの分布に関する研究 (第 I 報) : 三滝川上流のブユ相について(第 11 回大会講演要旨)

三重県におけるブユの分布に関する研究 (第 I 報) : 三滝川上流のブユ相について(第 11 回大会講演要旨)