Identification of hemocytes and study on hemogram of plum fruit moth Grapholita funebrana (Treitschke) (Lep.: Tortricidae)

The hemolymph circulatory system and hemocytes play a direct role in insect’s cellular defense. Changes in the shape, number and type of hemocytes are important indicators of an organism's reaction to infection or stress. In this study, larval hemocytes of Grapholita funebrana Treitsch were examined using light microscopy at 40 magnifications. Hemocytes were identified by Giemsa staining. Five types of hemocytes were identified in larvae of these insects as follows: granulocytes (GRs), plasmatocytes (PLs), oenocytoids (OEs), prohemocytes (PRs) and spherulocytes (SPs). Examination of the percentage of hemocytes in different larval instars of G. funebrana showed that granulocytes and plasmotocytes are the most abundant homocytes in fourth- and fifth-stage larvae. The differential number of hemocytes gradually increased as the larvae developed. Also, hemogram components including larval hemolymph volume and total number of hemocytes were determined. This study showed that volume of hemolymph and similarly the total number of hemocytes have a direct relation with the larval growth and body size. Grapholita funebrana is one of the most serious pests of plum orchards in Iran and immunological studies on this pest are rare. Thus, in the current study, types and number of cellular elements have been taken into consideration.