Effect of sublethal treatments with the insect growth regulator, Altozar, ZR-512, on blood constituents of Bombyx mori L. in relation to silk yield

Abstract

SummaryConcentrations of larval blood protein and blood lipid and density of blood in relation to the silk yield of Bombyx mori L. were estimated under the action of sublethal treatments (to give 0·0% kill of larvae) with the insect growth regulator Altozar, ZR-512.Results indicated that there was an inverse correlation between Altozar dosage and both weights of larvae and of the resulting cocoons, larval blood-protein and blood-lipid concentrations and density of blood. The decline in these attributes compared with the controls may indicate that a considerable proportion of the inhibitory effect of the growth regulator compound occurred during the development from larva to pupa.Considering the relationship between larval blood-protein or blood-lipid concentrations and wet weight of the resulting cocoons under the sublethal dosages of Altozar used, the present results confirm our findings concerning the strong relationship between the larval protein content and silk formation. There was a positive increase in the mean wet weight of the resulting cocoons as the protein and lipid concentrations increased.These experiments suggest that the sole source for the synthesis of silk protein is the protein present in the haemlymph of silkworms and dependent on the larval diet.