Karyotype Variation in the Aphid Sitobion rosaeiformis (Das) (Homoptera: Aphididae).

Abstract

Aphids tend to show karyotype variations because of the presence of holocentric chromo somes and thelytokous mode of reproduction . Structural heterozygosity and variation in chromosome number within species have been reported in some aphid species (Blackman 1971, Chattopadhay et al. 1982, Brown and Blackman 1988 , Blackman et al. 1990). These studies indicate that there is association between karyotypes and host plant in aphids . In this paper, karyotype variation in the aphid Sitobion rosaeiformis (Das) collected from Rosa sp. and Rubus ellipticus is reported. Materials and methodsThe populations of aphid Sitobion rosaeiformis (Das) (Subfamily-Aphidinae; Tribe -Macrosiphini) were collected from two different hosts Rosa sp. and Rubus ellipticus belonging to the family Rosaceae (Table 1). The collections were sent to CAB International Institute of Entomology, London for authentication and will be deposited in the Natural History Museum (BMNH) collection. Apterous, viviparous female aphids were taken and chromosome squash preparations were made from young embryos dissected from these aphids. Fresh material was used in this study . Embryos were given pretreatment in 0.7% sodium citrate solution for 30min and then fixed in a fresh mixture of 1:3 acetic ethanol. After 25min embryos were transferred to a drop of 50% acetic acid on a glass slide. A coverslip was gently put on the material and it was then squashed, first by tapping and then by applying thumb pressure. Coverslips were dislodged off the slides with a sudden jerk. The slides and coverslips were dried and stained with 2% Giemsa stain at pH 6.8.

Karyotypic Studies on Aphids from Himachal Pradesh (North-western Himalayas), India.

“…and 2n=18 in S. rosaeiformis and S. miscanthi. Gautam and Dutta (1994) reported karyotype variation in S. rosaeiformis with 2n=14 and 18. Blackman (1980) has earlier reported 2n=16 in S. wikstroemiae and S. ptericolons and 2n=18 in S. nigronectarium.…”

“…At present, over 4000 species of aphids have been reported the world over and chromosomes of about 20% of these species have been reported by different workers (see Gautam et al 1993). In a very recent study on the chromosomes of aphids from North-western Himalayas, Dutta and Gautam (1993) reported the chromosomes of 52 aphid species.…”

The karyotype studies of some aphid species (Aphidoidea: Hemiptera) from Niğde province in Türkiye

“…Blackman (1980) presented chromosome numbers of 180 aphid species, and pointed out that diploid chromosome numbers of them range from 6 [Sarucallis kahawaluokalani (Kirkaldy, 1907)] to 72 [Amphorophora (Amphorophora) sensoriata Mason, 1923)]. Dutta & Gautam (1994) provided information about the chromosomal compositions of 52 aphid species belonging to 34 genera and 21 of them were reported for the first time. The sex diagnosis and karyotype of Cavariella aegopodii (Scopoli, 1763) and Tuberolachnus salignus (Gmelin, 1790) were detected in different localities of India in a study by Dhatwalia & Gautam (2009).…”