Composition of the Blood of Japanese Beetle (Popillia japonica Newman) Larvae

Abstract

The blood of the Japanese beetle larva has a water content of 91.2% and an osmotic pressure of 12.4 atm. at 0[degree]C. The organic constituents are 3 times as effective osmotically as are the inorganic salts. The blood contains 248 mg. % reducing compounds of which 179 mg. % are not fermentable. It contains 1300 mg. % N, of which 800 mg. % are present in the protein fraction, 500 mg. % in the nonprotein fraction, and 240 mg. % in the amino acid fraction. The avg. concn. of inorganic ions, expressed as mg. % are: chlorides, 67.5; Na, 46.5; K, 37.2; Ca, 31.6; Mg, 47.1; and inorganic phosphates, 15.2. The Na index is low, and the Mg index is high. Contrary to results obtained with other insects with a low Na index, the blood of the Japanese beetle larva also has a low K index.