Immature stages of some aphidophagous syrphid flies of India (Insecta, Diptera, Syrphidae)

Immature stages, viz. egg, larva and puparium, of six species of the economically most important syrphid flies, Scaeva latimaculata (Brunetti), Ischiodon scutellaris (Fabricius), Episyrphus altemans (Macquart), Sphaerophoria Indiana Bigot, Metasyrphus confrater (Wiedemann), and M. latilunulatus (Collin), have been studied. These species are voracious feeders on three aphid species, Lipaphis erysimi (Kaltenbach), Myzus persicae (Sulzer) and Brevicoryne brassicae (L.), which are serious pests of mustard, Brassica campestris L.     

Biology, immature stages and rearing of cocoa-capsids (Miridae: Heteroptera)

Some aspects of the biology of four West African capsid pests of Cocoa, Distantiella theobroma (Distant), Sahlbergella singularis Haglund, Bryocoropsis laticollis Schumacher and Helopeltis corbisieri Schmitz (Miridae: Heteroptera) are briefly summarized. Their immature stages are described and sketched in detail. Keys to distinguish all the larval stages are given and the techniques for rearing them reviewed. The systematics of Bryocorinae is discussed.     

Structure and function of the dorsal abdominal gland and defence mechanism in cocoa-capsids (Miridae: Heteroptera)

An account is given of the structure of the dorsal abdominal gland in Distantiella theobroma, Sahlbergella singularis, Bryocoropsis laticollis and Helopeltis corbisieri. The function is discussed, and defence mechanisms in the four species are described.     

Syncytes during male meiosis resulting in 2n pollen grain formation in Lindelofia longiflora var.falconeri

Lindelofia longiflora (Royle ex Benth.) Baill.var.falconeri (Cl.) Brand (Family:Boraginaceae) is investigated cytologically (n =12) for the first time from the cold deserts of Pangi Valley,Chamba District (Himachal Pradesh) in India.We report the formation of syncytes and 2n pollen grains in the species.During meiosis,the majority of the pollen mother cells (PMCs) exhibited 12 bivalents,equal segregation of chromosomes during anaphases,regular tetrads,and normal-sized pollen grain formation.Occasionally,two proximate PMCs fused during the early stages ofprophase-I and resulted in the formation of syncytes.The frequency of syncytes in the accession is rather low,at 25 out of 1866 (1.33％).Such syncyte PMCs are detectable during meiosis due to their larger size compared to typical PMCs.The syncytes or polyploid cells showed normal 24 bivalents and depicted perfectly regular meiotic course.But the products of such PMCs yield 2n or larger sized pollen grains that are almost double the size of typical normal or n pollen grains.The origin of syncytes as a consequence of the fusion of meiocytes during the early stages of meiosis-I could be attributed to low temperature stress conditions prevailing in the Pangi Valley,where temperature during May and June dip to below freezing,the time the plants enters the reproductive/flowering bud stage.It is possible that such apparently fertile 2n pollen grains originating from syncytes might play a role in the origin of intraspecific polyploids in the species.     

Syncytes during male meiosis resulting in 2n pollen grain formation in Lindelofia longiflora var. falconeri

Abstract Lindelofia longiflora (Royle ex Benth.) Baill. var. falconeri (Cl.) Brand (Family: Boraginaceae) is investigated cytologically (n= 12) for the first time from the cold deserts of Pangi Valley, Chamba District (Himachal Pradesh) in India. We report the formation of syncytes and 2n pollen grains in the species. During meiosis, the majority of the pollen mother cells (PMCs) exhibited 12 bivalents, equal segregation of chromosomes during anaphases, regular tetrads, and normal‐sized pollen grain formation. Occasionally, two proximate PMCs fused during the early stages of prophase‐I and resulted in the formation of syncytes. The frequency of syncytes in the accession is rather low, at 25 out of 1866 (1.33%). Such syncyte PMCs are detectable during meiosis due to their larger size compared to typical PMCs. The syncytes or polyploid cells showed normal 24 bivalents and depicted perfectly regular meiotic course. But the products of such PMCs yield 2n or larger sized pollen grains that are almost double the size of typical normal or n pollen grains. The origin of syncytes as a consequence of the fusion of meiocytes during the early stages of meiosis‐I could be attributed to low temperature stress conditions prevailing in the Pangi Valley, where temperature during May and June dip to below freezing, the time the plants enters the reproductive/flowering bud stage. It is possible that such apparently fertile 2n pollen grains originating from syncytes might play a role in the origin of intraspecific polyploids in the species.     

<Emphasis Type="Italic">LIG1</Emphasis> polymorphisms: the Indian scenario

Elucidation of the genetic diversity and relatedness of the subpopulations of India may provide a unique resource for future analysis of genetic association of several critical community-specific complex diseases. We performed a comprehensive exploration of single nucleotide polymorphisms (SNPs) within the gene DNA ligase 1 (LIG1) among a multiethnic panel of Indian subpopulations representative of the ethnic, linguistic and geographical diversity of India using a two-stage design involving DNA resequencing-based SNP discovery followed by SNP validation using sequenom-based genotyping. Thirty SNPs were identified in LIG1 gene using DNA resequencing including three promoter SNPs and one coding SNP. Following SNP validation, the SNPs rs20580/C19008A and rs3730862/C8804T were found to have the most widespread prevalence with noticeable variations in minor allele frequencies both between the Indian subpopulation groups and also from those reported on other major world populations. Subsequently, SNPs found in Indian subpopulations were analysed using bioinformatics-based approaches and compared with SNP data available on major world populations. Further, we also performed genotype–phenotype association analysis of LIG1 SNPs with publicly available data on LIG1 mRNA expression in HapMap samples. Results showed polymorphisms in LIG1 affect its expression and may therefore change its function. Our results stress upon the uniqueness of the Indian population with respect to the worldwide scenario and suggest that any epidemiological study undertaken on the global population should take this distinctiveness in consideration and avoid making generalized conclusions.