A Comparison of Hemocytes in Phasmatodea and Blattodea Species

The aim of this study was to characterize and quantify hemocyte types in the Indian stick insect Carausius morosus (Phasmatidae) and in the tropical cockroaches Blaberus craniifer and Archimandrita tessellata (Blaberidae) cultivated in an insectary. Plasmatocytes, prohemocytes, granulocytes, coagulocytes and spherulocytes were found in the cockroaches. Of the mentioned cells, the Indian stick insect lacks spherulocytes. C. morosus had the lowest total hemocyte count (THC) and B. craniifer had the highest THC. However, the number of plasmatocytes was high in all the insects, but was more pronounced in C. morosus. In cockroaches, as expected, the differential hemocyte count (DHC) was similar, and contained a high number of spherulocytes. The number of coagulocytes was relatively low in all species. Our results contribute to insect hemocyte data and confirm the need for further intensive research into the function of hemocytes and into evolutionary ecology.