• T Manoharan

      Articles written in Proceedings – Animal Sciences

    • Toxic and sublethal effects of endosulfan onBarhus stigma (Pisces: Cyprinidae)

      T Manoharan G N Subbiah

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      Toxicity and the effect of sub-lethal concentrations of endosulfan on a fresh water fishBarbus stigma had been studied. Endosulfan proved to be lethal toB. stigma at a concentration of 0·01 ppm and above. The LC50 was 0·0043 ppm and the sub-lethal concentration was 0·003 ppm and below. At sub-lethal concentrations the fish exhibited erratic swimming activity and at lethal concentrations it lost the sense of balance. The rate of feeding was reduced by 5·94% to 9·02% and assimilation by 6·44 to 9·60% in different sub-lethal concentrations. Growth (weight) retarded from 11·6mg/day in the control fish to. 7·3, 6·0 and 5·1 mg/day in the endosulfan treated fishes. Respiratory rate of the pesticide treated fish also dropped by 10 to 16·6%. Due to. the over all effect of the toxicity, the fish,B. stigma comparatively showed a poor nutritive value by displaying a drop of nearly 35% in the organic constituents.

    • Influence of food plants on the food utilization and chemical composition ofHenosepilachna septima (Coleoptera: coccinellidae)

      G Ganga J Sulochana Chetty R Senthamil Selvi T Manoharan

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      Influence of three food plants,viz Memordica charantia, Luffa acutangula, andTrichosanthus anguina on the food utilization and chemical composition ofHenosepilachna septima has been studied. The rate of conversion and conversion efficiencies were higher inT. anguina fed beetles. The rate of conversion was positively correlated with the protein content of the food plants. The organic constituents ofH. septima specially protein and lipid increased when fed on the different food plants. Greater increase of all the organic constituents occurred when the insect was fed on the nutrient richT. anguina than when fed on other food plants.

    • Effect of food quality on fecundity ofMylabris pustulata (Coleoptera: Meloidae)

      T Manoharan S Chockalingam K P S Jeyachandran

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      Observations on the fecundity ofMylabris pustulata maintained on two different food plantsIpomoea cornea andIpomoea tuberosa, with males and females reared separately on the flowers of these two host plants are discussed.Mylabris pustulata reared onIpomoea cornea laid 144±30·80 eggs while that onIpomoea tuberosa only 93±38·87 eggs. The chemical composition of the flowers ofI. cornea andI. tuberosa revealed that protein concentration is greater inIpomoea cornea (4·88%) thanIpomoea tuberosa (4·64%). The quantity of food ingested is also greater when reared onIpomoea cornea (1055 mg). In the light of these observations it is presumed that the food rich in protein concentrations is among the principal factors influencing fecundity.

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