Chromosomes of Syrphidae

This report describes the karyotypes of fourteen species of the tribe Chrysotoxini (Diptera, Syrphidae) with the single genus Chrysotoxum. The species are listed in the Table on p. 240. All have 2n=10 chromosomes, usually consisting of short apparently telocentric sex chromosomes plus two subtelocentric and two submetacentric pairs of autosomes.     

Chromosomes of Syrphidae

In this report the karyotypes of 54 species of the tribe Milesiini and of four species of the tribe Myoleptini are described in detail with illustrations and idiograms. These species belong in the genera Lejota, Myolepta, Blera, Calliprobola, Criorhina, Hadromyia, Milesia, Somula, Sphecomyia, Spilomyia, Syritta, Temnostoma, Tropidia and Xylota. Six species have 2n = 8 chromosomes, 35 have 2n = 10 (including Xylota nemorum which has about 20 extra microchromosomes in some specimens), 15 have 2n = 12, one has 2n = 14, and Somula decora has 2n = 10 large chromosomes plus about eight microchromosomes. The mean total complement length (TCL) for 347 complements analysed in these tribes was 53.7 but there is great variation between TCL's of complements analysed even from a single fly. Karyotypes of species of Myolepta in the Myoleptini resemble in certain respects those of species of Tropidia in the Milesiini. Our observations support Currran's transfer of Lejota cyanea to the Milesiini. The 2n = 12 karyotypes of species of Blera, Criorhina, Lejota, Milesia, and to a lesser extent Sphecomyia, have some features in common. Spilomyia species have rather distinct 2n = 10 karyotypes. Certain species in Calliprobola, Syritta and Hadromyia are karyologically similar to some species of the genus Xylota in which species studied fall into fairly distinct karyological groups. These observations provide clear evidence of the accumulation of karyotypic variations in the origin of species in these two tribes.     

Chromosomes of Syrphidae. VI. The tribe Pipizini

The karyotypes of 24 species of the tribe Pipisini (Diptera: Syrphidae) are described and illustrated. Nearly all the species of Neocnemodon, Pipiza and Pipizella have 2n=8 chromosomes consisting of a short telocentric XY pair and three metacentric pairs increasing in relative length from long to very long. Pair II chromosomes in several Pipiza species have high metacentric to low submetacentric arm ratios. One Parapenium species is tentatively reported as having five pairs and another five or six pairs. The karyological evidence favours placing the tribe Pipizini in the subfamily Syrphinae rather than in the subfamily Milesiinae.     

辽宁食蚜蝇科昆虫名录(双翅目:食蚜蝇科)

本文报道了辽宁省食蚜蝇科昆29属53种的名录和分布。     

中国食蚜蝇科昆虫研究进展

食蚜蝇Syrphidae是双翅目昆虫中一类很重要的资源昆虫和天敌昆虫,在控制蚜虫、自然界传粉等方面有很重要的作用,同时也是仿生学等研究的重要实验材料。文章介绍国内食蚜蝇科昆虫最近几年的分类学、生态学、生物学习性及生物防治的研究现状。     

Chromosomes of kinetoplastida

We have compared chromosome-sized DNA molecules (molecular karyotypes) of five genera (nine species) of kinetoplastida after cell lysis and deproteinization of DNA in agarose blocks and size fractionation of the intact DNA molecules by pulsed field gradient (PFG) gel electrophoresis. With the possible exception of Trypanosoma vivax and Crithidia fasciculata, all species have at least 20 chromosomes. There are large differences between species in molecular karyotype and in the chromosomal distribution of the genes for alpha- and beta-tubulin, rRNA and the common mini-exon sequence of kinetoplastid mRNAs. In all cases, the rRNA genes are in DNA that is larger than 500 kb. Whereas T. brucei has approximately 100 mini-chromosomes of 50-150 kb, only few are found in T. equiperdum; T. vivax has no DNA smaller than 2000 kb. As all three species exhibit antigenic variation, small chromosomes with telomeric variant surface glycoprotein genes cannot be vital to the mechanism of antigenic variation. The apparent plasticity of kinetoplastid genome composition makes PFG gel electrophoresis a potentially useful tool for taxonomic studies.     

Flower visiting by hoverflies (Syrphidae)

An account is given of a study of resource-partitioning in hoverflies (Syrphidae) which feed almost exclusively on flowers. Suggestions are made for school project work using hoverflies.     

Chromosomes of Aspidogaster conchicola

Analysis of mitotic and meiotic chromosome spreads of Aspidogaster conchicola (Trematoda: Aspidogastrea) reveals a diploid number of 10 for this species. Haploid sets containing 5 bivalents confirm the diploid number. The karyotype consists of one pair of comparatively long subtelocentric chromosomes and four pairs of shorter acrocentric elements. The results are discussed in comparison with existing data on chromosomes of aspidogastrean species and other related helminth groups.