Abstract: Changes in the levels of haemolymph cations of 5th instar larvae of Pure Mysore, NB₄D₂ and CSR₂ fed on M-5, S-36 and V-1 mulberry varieties were investigated. The larval haemolymph showed low Na⁺ and very high K⁺ and Mg²⁺ concentrations and moderately high Ca²⁺ like the mulberry leaf. The haemolymph cation levels increased significantly during the active feeding period of the larva. A negative correlation existed between the levels of cations in haemolymph and excreta. The haemolymph cation levels were held by controlled excretion of the cations. The rates of elimination of cations were lower during feeding stages than during non feeding stages. The haemolymph cation levels of bivoltine races were about 30% higher than the multivoltine PM. The impact of race was significantly more than that of mulberry variety or ontogeny in upward changes in haemolymph cations.

Key words: Bombyx mori, mulberry leaf, nutrition, haemolymph, cation level