HAEMOLYMPH SPECIFIC GRAVITY, SOLUBLE TOTAL PROTEIN AND TOTAL SOLIDS OF PLANT-REARED, NORMAL, AND PARASITIZED DIET-REARED TOBACCO HORNWORM LARVAE

Specific gravity, soluble total protein, and total solids of the haemolymph from fourth and fifth instar larvae and pharate pupae of the tobacco hornworm, Manduca sexta, were determined. Comparisons were made between insects reared on synthetic and natural diets and between parasitized and non-parasitized insects reared on synthetic diet. Values for all three parameters of diet-reared larvae were significantly higher than those for plant-reared larvae, but no differences were observed between their pharate pupae. Values for parasitized insects were more variable, but specific gravity and total solids were significantly lower than, or in some cases equal to, controls, and total soluble protein was significantly greater than in the controls. Excellent correlation between the three parameters was found for diet-reared larvae and less accurate, but useful, correlations were found for plant-reared larvae. There was very poor correlation between soluble protein and specific gravity or total solids in parasitized larvae. © 1969.