Phagocytic haemocytes in unfixed Galleria mellonella larvae

Abstract

Phagocytosis by the haemocytes of unfixed last instar larvae of the greater wax moth, Galleria mellonella (L)., was studied by injecting foreign materials into the haemocoele. Starch granules, sheep erythrocytes, latex particles, Chinese ink, Sarcina lutea, and Staphylococcus epidermidis were readily phagocytized by mitotically dividing cells, plasmatocytes, and adipohaemocytes by forming vacuoles around the material or engulfing it with pseudopodia. Spherule cells and oenocytoids showed no phagocytic ability. Phagocytosis was sometimes associated with the following changes in the haemocyte picture: (a) an increase in the number of circulating adipohaemocytes when larvae were injected with starch, sheep erythrocytes, Sarcina, and Staphylococcus; (b) the change in adipohaemocyte level was inversely proportional to the plasmatocyte level; and (c) an increase in haemolymph volume followed injections of sheep erythrocytes, Chinese ink, Sarcina, and Staphylococcus.