Haemocyte variations in 35 species of grasshoppers and locusts

Abstract

Introduction: Grasshoppers and locusts are widely distributed worldwide, causing significant losses in agriculture. The origin and functions of their haemocytes are not entirely understood. Objectives: Insect haemocytes arbitrate cellular defence and participate in humoral defences. Due to their importance, the haemocytes of 35 species of grasshoppers and locusts from China were morphologically examined in this study. We aim to highlight a simple method for the morphological examination of insect haemocytes. Methods: The haemocytes were observed, counted and compared under a light microscope after Wright-Giemsa staining. Results: High complexity in form and shape were observed in the haemocytes. These include prohaemocytes, plasmatocytes, granulocytes, vermicytes, podocytes and megakaryocytes. No clear relationship was seen between the haemocyte type and their phylogenetic relationship among the three families examined. The high abundance of plasmatocytes and granulocytes suggests their importance in the immunity of grasshoppers and locusts. The minor haemocyte populations including prohaemocytes, vermicytes and podocytes may not be always present in individuals. Conclusion: All examined species shared similarities in their haemocyte types. Wright-Giemsa staining is a simple and efficient method for evaluating haemocytes.