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Lipid and Water Contents in Silkworm, Bombyx Mori L. Race Bsr-832 During Metamorphosis.

M.A. Qader
Senior Research Officer
BSRTI, Rajshjahi.

M.T. Haque
Senior Reseach Officer
BSRTI, Rajshjahi.

S.U. Ahmed
BSRTI, Rajshjahi.

Abstract/ Executive Summary:

Lipid and water contents during various developmental stages in the silkworm, Bombyx mori L. race BSR-832, were determined and their correlation coefficients were examined. The lipid content decreased gradually from 1st instar (4.49%) to the fourth instar larva (2.71%) and then increased upto the adult stage (Male, 19.51% and Female, 6.05%). Throughout the period of larval to adult stages, the water content decreased from 84.28% to 67.68% with increase in lipid content. The male pupa and male moth contained more lipid (10.79% and 19.51% respectively) than the female pupa and female moth (6.09% and 6.05% respectively) during pupa to adult stage. The lipid content decreased with the age of eggs. Significant negative correlation coefficients were observed between lipid and water contents which varied with the age of the insect.

Keywords: Lipid and water contents in silkworm, Metamorphosis, Various developmental stages.

Location: Bangladesh Sericulture Research and Training Institute

Start Date: 01-01-1982

End Date: 31-12-1984

Program Area: Resource Development and Management

Commodity: Silkworm

Objectives:

To reinvestigate and assess the amount of lipid and water content in the silkworm, Bombyx mori L. race BSR-832 during its various developmental stages.

Methodology:

Eggs, larvae, pupae and moths of different stages of metamorphosis of B. mori L. race BSR-832 were used for this experiment. The experiment was divided into four groups. The first group consisted of 1, 4 and 8 days old eggs; the second consisted of living worms of different instars; the third consisted of pupae with sexual dimorphism of early, middle and late stages; and the fourth group consisted of moths with dimorphism before and after mating for three hours. The worms were starved for 24 hours in order to clear out the gut. Lipid content was estimated by the Folch et al. (1957) method modified by Abasa (1972). The eggs and worms were made morbid by Chloroform vapour and were dried in the oven at HO°C until the sample weignt was constant. Moisture percentage was calculated. The dry eggs and worms were then crushed, shaken well with 20 ml of Chloroform-Methanol mixture (2:1, v/v) in a stoppered conical Hask and kept overnight in a dark place. Next day it was filtered using fat free filter paper and the residue was washed with 15 ml of Chloroform-Methanol mixture (1:1, v/v), and lastly with 10 ml Petroleum Ether (boiling point 60°-80°C). The total filtrate was collected in a porcelain crucible ( 50 C.C ) and kept in an oven at 80°C for three hours. When the filtrate was completely evaporated to dries, the lipid was weighed until constant weight was obtained. The experiment was repeated thrice and lipid content was expressed in per cent.

Source of Information: Bangladesh Journal of Zoology. 16(1), 1988 : 45-49

Article Link (Online Journal):

Funding Source:

1. Government

Budget:

Total Budget (Tk.) :

Achievement/Findings:

The results obtained in the present investigation suggest that lipid contents decreased from egg to at fourth instar larvae indicating utilization of lipid during embryogenesis and early stages of development. Similar results were reported by Nirmierko ct al. (1956) and Gupta & Pathak (1984) in B. mori. According to Gupta & Pathak ( 1984 ) lipid contents decreased gradually from second instar to fourth instar but the present study showed that lipid contents decreased gradually from first instar to fourth instar and then increased in the fifth instar. The results obtained in the present investigation (19.51 % in the male and 5.92% in the female) also conform, with the above findings. Nirmierko et al. (1956) reported that in B. mori the newly emerged male contains 48% and female contains 25% lipid. It may be concluded that with the increase in lipid content water content would decrease significantly during sexual dimorphism and that the male contains more lipid than the female in B. mori L. race BSR-832.

Knowledge Management: Journal