• Volume 98, Issue 2

      March 1989,   pages  77-148

    • Effect of feeding tender and senescent leaf byEupterote mollifera and tender leaf and flower bySpodoptera exigua on food utilization

      M Senthamizhselvan J Muthukrishnan

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      Food consumption and utilization efficiencies ofEupterote mollifera fed on tender leaf were higher than those of counterparts ingesting senescent leaf, while inSpodoptera litura individuals fed on flower showed higher values in comparison to those that consumed tender leaf. Food utilization parameters of these insects depend upon the nutritional quality of the food.

    • Effect of diethylstilbestrol on growth and food conversion of common carp,Cyprinus carpio (Linn.)

      T Nanjundappa T J Varghese

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      Diethylstilbestrol, an estrogen, was administered through diet to fingerlings of common carp,Cyprinus carpio at concentrations of 0, 1, 3 and 5 ppm over a period of 98 days and its effects on growth and food conversion efficiency were evaluated. The experiment was conducted in 12 cement cisterns of 25 m2 area each. Fishes were fed daily at the rate of 5% of body weight. Diethylstilbestrol incorporated diets induced faster growth and better food conversion efficiency as compared to the control. Among the dosages tried, 3 ppm treatment yielded the best growth. The faster growth in diethylstilbestrol treated groups was significantly different (P<0·05) from that of the control.

    • Seasonal changes in the timing of hopping and feeding activities of a tropical bird (Estrilda amandava) under natural photoperiod

      P Subramanian R Subbaraj

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      The timings of onset and end of hopping and feeding activities of the birdEstrilda amandava, were studied under natural light-dark cycles and they are found to keep pace with the timings of sunrise and sunset. The onsets of hopping and feeding occurred at different timings of twilight and they vary over the seasons. The phase angle difference (ψ) of hopping always shows a considerable phase lead relative to feeding which also varies over the seasons and thus suggests that there may be two endogenous oscillators, one responsible for hopping and the other for feeding.

    • Pheromonal and hormonal control of reproduction in the freshwater prawn,Macrobrachium kistnensis

      R Nagabhushanam P R Machale R Sarojini

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      In the freshwater prawnMacrobrachium kistnensis reared with males, the ovarian development occurred normally, whereas it was delayed in the absence of males. Testis and vas deferens extracts when added to the water in which females are being reared brought about normal development of ovary in comparison to those which were reared in boiled water or ‘female water’ alone. Therefore, mature males appear to be producing a pheromone which is necessary for the ovarian development of the female and the source of this might be vas deferens or testis. On the other hand, the central nervous tissue extracts stimulated vitellogenesis in oocytes. In particular, the brain extracts were more effective than those of thoracic ganglion in inducing this response. Thus, in the present study ovarian maturation and vitellogenesis appear to be under the pheromonal and hormonal controls.

    • Consumption and utilization of food in different instars of muga silkwormAntheraea assama Westwood

      A Barah M C Goswami M V Samson

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      An investigation was carried out to find out the nutritional parameters viz. consumption, assimilation and tissue growth etc. of muga silkwormAntheraea assama Westwood (Lepidoptera: Saturniidae) by rearing it indoor on som twigs. During 32 days of its larval life, the total consumption of an individual was 33·925 g of which 21·295 g were assimilated by the insect. About 80·1% of the total consumption took place in the fifth instar alone. The weight of one full grown larva was computed at 13·9304 g. The assimilation and tissue growth were found positively correlated with the consumption as well as with the age of the larva. The approximate digestibility was negatively correlated to the amount of food consumed. Efficiency of conversion of ingested and digested food increased in the first 4 instars and declined in the fifth instar.

    • Osmoregulatory ability ofPenaeus indicus H Milne Edwards in relation to varying salinities

      A D Diwan A Laxminarayana

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      JuvenilePenaeus indicus osmoregulated well between 3–26‰ S for 24 and 48 h duration with isosmotic points ≈S 18‰ and ≈S 14‰ respectively. Adults also showed good osmoregulatory capability between 5–30‰ S with isosmotic points ≈ S 21‰ and ≈S 17‰ for 24 and 48 h duration respectively. A duration of 48 h is essential for prawns to adjust to the new medium. Influence of various neuroendocrine centres on the osmolal concentration of haemolymph was studied. In eyestalk ablated prawns osmolal concentration decreased with time and reached a lowest after 48 h. Eyestalk ablated prawns injected with extracts of eyestalk, brain and thoracic ganglia did not show any decrease in the values with time but remained on par with the values of normal ones.

    • Hydroxysteroid dehydrogenases in the ovary of larva, pupa and adult eri silkworm,Philosamia ricini (Hutt.)—A histochemical study

      H K Hurkadli M A Hooli

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      Histochemical analysis of the various developmental stages ofPhilosamia ricini showed the presence of Δ5-3β-hydroxysteroid dehydrogenase, 17β-hydroxysteroid dehydrogenase, 11β-hydroxysteroid dehydrogenase and glucose-6-phosphate dehydrogenase in the lamellar epithelial cells, precursors of oocytes, nurse cells and follicle epithelial cells of the germarium of larva and pupa, oocyte-nurse cells complex, follicle epithelial cells of immature and mature follicles and intermediate cells of pupa suggesting that these tissues are able to metabolize Δ5-3β-hydroxysteroids, 17β-hydroxysteroids and 11β-hydroxysteroids to corresponding ketosteroids.

    • Sodium coupled nutrient transport in the midgut tissue of the silkworm,Bombyx mori L.

      M V V Subramanyam S K Sarangi

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      Fifth instar larvae ofBombyx mori were administered with additional Na+ ion orally. The concentration of Na+ increased and that of K+ decreased significantly in the haemolymph within 24 h. There was no marked difference in the ionic concentration of the midgut cell while K+ increased in the gut content. The protease activity increased significantly in gut lumen with a resultant increase in amino acid concentration, which showed a decrease in gut tissue and haemolymph. The protein content did not show significant change in gut lumen, while in gut tissue and haemolymph it decreased markedly. The results are discussed in relation to the Na+-linked nutrient transport mechanism in the gut epithelium ofBombyx mori.

    • Caryophylliasis in the catfish,Clarias batrachus L.: some histopathological observations

      Reba Chakravarty Veena Tandon

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      The extent of damage to the intestine caused by the caryophyllid cestodes,Lytocestus indicus, Djombangia penetrans, and by multiple infections comprising several species of caryophyllids in the cat fish,Clarias batrachus L. is studied.Djombangia penetrans produced large nodules in the intestinal wall.Lytocestus indicus, being less deeply penetrative, caused ulceration of the affected tissue, with hyperplasia of the muscularis in severe cases of infection. Pathogenicity due to multiple infections was minimu, apparently limited to denudation of the mucosal folds.

    • Insecticide induced hematological changes in pigeons

      Aditya Mandal Pulak Lahiri

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      Hematological responses of bluerock pigeon (Columba livia Gmelin) were studied after oral administration of chlordane (a cyclodiene) fenitrothion (a phosphothioate) and carbaryl (a carbamate) for one week. Comparable hematological disorders were induced by these insecticides which include reduction in total count of peripheral erythrocytes, hemoglobin content, hematocrit and total cellularity of spleen. Total count of peripheral leucocytes, on the otherhand, increased with marked heterophilia together with lymphopenia and monocytopenia. Both bleeding and clotting time became conspicuously prolonged in the experimental birds. The results indicate potential to use hematological responses for rapid on the spot assay of insecticide toxicity in non-target animals.

    • Ontogeny of aggressive and submissive behaviour in free living rhesus monkeys (Macaca mulatta)

      Rajbir Singh

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      Twenty rhesus monkeys of various age-sex classes were observed by focal animal and one-zero sampling technique for 12 months at Galta hillocks near Jaipur (Rajasthan). Behavioural elements sampled were screech, scream, bark, threat, chase, clasppull, bite, fear grimace, lip-smack and submit. These elements were categorized into aggressive and submissive behaviours by pooling the frequencies of elements. Mean per cent frequencies were derived and analysed by ANOVA, trend analysis, Kruskal Wallis one way ANOVA and Mann-Whitney ‘U’ test. It was found that submissive behaviour among females and aggressive behaviour among males changed with age. The findings have been interpreted on the basis of social conditions and the typical spatial position of the age-sex class within the group space/structure.

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