Volume 99, Issue 1
January 1990, pages 1-89
pp 1-17 January 1990
Fine structure of the regional differentiation of the ductus ejaculatorius simplex (EJ1, EJ2, EJ3) along with the role of their secretions in sperm activation and motility in two Noctuid species,Heliothis armigera (Hübner) andSpodoptera litura (Fabricius) (Lepidoptera). I. Fine structure and function of simplex 1 (EJ1)
The common unpaired ejaculatory duct or simplex of male reproductive tract ofHeliothis armigera andSpodoptera litura, on the basis of morphology and anatomy, are broadly distinguished into EJ1, EJ2 and EJ3 regions. The proximal region (EJ1) of common duct to the ductus ejaculatorius duplex characteristically contains transparent elastic gelatinous secretion which is capable of sperm activationin vitro. The immotile spermatozoa within the duplex are induced-in vitro activated by diluting the same to 0·15 M in HEPES-KOH buffer, maintaining pH at 7. The activation is facilitated by the addition on 10mg/ml bovine serum albumin and activation is triggered by an addition of a small fraction of activator substance taken from EJ2. EJ1 of both species exhibit only a single layered epithelium. Merocrine and apocrine are the mode of secretion occurring inHeliothis armigera while merocrine is the only mode of secretion occurring in EJ1 ofSpodoptera litura.
pp 19-38 January 1990
Fine structure of the regional differentiation of the ductus ejaculatorius simplex (EJ1, EJ2, EJ3) along with the role of their secretions in sperm activation and motility in two Noctuid species,Heliothis armigera (Hübner) andSpodoptera litura (Fabricius) (Lepidoptera). II. Fine structure and function of simplex 2 (EJ2)
The mid region (EJ2) of common ejaculatory duct is characterised by secreting intensity varying white viscous secretion together with a small segment of the milky white viscous secretion. The milky white segment possesses as the optimum amount of activator, high molecular weight protein between 30,000 and 60,000 capable of disaggregating eupyrene sperm bundles besides possessing the activating substance.
pp 39-52 January 1990
The antibiotic effects of 3 phenolic substances viz. resorcinol, gallic acid and phloroglucinol on the cotton bollwormHeliothis armigera Hubner were evaluated with particular reference to the feeding regimes, survival and pupation. Some of the characteristic antibiotic effects observed for resorcinol and phloroglucinol include reduction in consumption index and approximate digestability, increased efficiency of conversion of ingested food and efficiency of conversion of digested food, extended larval duration and high mortality. However, there was no alteration in the various food utilization efficiencies in the case of gallic acid treated individuals. The defensive response of the larvae to these toxic substances seems to be excessive defaecation. Frass analysis through thin-layer chromatography and ultraviolet characterisation indicated the presence of the ingested antibiotics, opening further avenues of investigation on the possible role of these antibiotics present in the frass in biological control.
pp 53-56 January 1990
The effect of exposure to dimethoate, an organophosphorus insecticide, on the activity of soluble and membrane-bound fractions of acetylecholinesterases from the brain of the Indian razor-fish,Notopterus notopterus was studied. The fishes were exposed to a concentration of 2 ppm of the insecticide for a period of 4 weeks. The two fractions of the enzyme exhibited a reduced efficiency, as indicated byVmax/Km ratios. The exposure to the insecticide resulted in 96·25% reduction in VmJKm for the membrane-bound fraction and 68·7% reduction in the corresponding value for the soluble enzyme as compared to those of the control set of fishes.
pp 57-66 January 1990
Biochemical analysis of 4 rice varieties and a weed showed that the total free amino acid content was greater in the susceptible variety TN 1 than in Ptb 2, Ptb 7 and Ptb 18 which are resistant to both the species of green leafhoppers. However, the weed Leersia hexandra the most suitable host ofNephotettix nigropictus, had the lowest amount of free amino acids. No apparent differences were observed in relation to sucrose, glucose and fructose content in the test varieties. Total phenol content was the highest inLeersia hexandra followed by resistant varieties, while it was the lowest in the susceptible rice variety.
Bioassay of plant extracts in various organic solvents showed that the chloroform and acetone extracts of the resistant variety Ptb 18 were phagodeterrents to either species of green leafhoppers, while the extract of the susceptible variety with the same solvent was phagostimulant. Of the various chemicals bioassayed, sucrose (5%) among the sugars tested, was found to be highly stimulatory for feeding. Among amino acids, serine, alanine and glutamine were feeding stimulatory in nature. On the other hand, most of the amino acid derivatives, all organic acids and phenolic compounds tested exhibited phagodeterrency.
pp 67-72 January 1990
Studies on polyacrylamide gel electrophoresis were undertaken for analysing haemoglobins and eye lens proteins in 6 Indian rodent genera from chaemotaxonomic point of view. The report reveals a distinct segregation ofRattus andBandicota fromMus and other two murine genera. Revisionary studies of the entire subfamily Murinae for reconsidering the taxonomic placement ofRattus andBandicota in the subfamily has been suggested.
pp 73-78 January 1990
Earthworm density and diversity have been studied in a sandy loam site and a clay loam site, each comprising of 50 locations, at Madras.Lampito mauritii is the dominant species in the sandy loam while it isOctochaetona serrata in the clay loam. The indices of dominance, diversity and dissimilarity have been estimated and discussed in relation to the distribution of earthworms.
pp 79-89 January 1990
One-hectare plots were sampled for bird species diversity in the Uttara Kannada district. These plots represented well-preserved evergreen/semievergreen forests, secondary/moist deciduous forests showing different levels of degradation by man and plantations of teak, eucalypts and betelnut. It was found that the betelnut plantation and the evergreen/semievergreen forests had the least bird species diversity ofH′ = 2.58 and 2.61 respectively. The eucalypt and teak plantations hadH′ = 2.69 and 2-92 respectively. In the secondary/moist deciduous forests it ranged from 2.80–3.39. Despite the apparent increase in diversity in the man-modified vegetation types, it was found that there was a gradual displacement of the bird species composition from what was typical to the evergreen forests to those of more urban and scrubby habitats in these man-modified vegetation types. This was particularly so in the eucalypt plantation.