title: The relative abundance of hemocyte types in a polyphagous moth larva depends on diet.
abstract: Hemocytes are crucial cells of the insect immune system because of their involvement in multiple immune responses including coagulation, phagocytosis and encapsulation. There are various types of hemocytes, each having a particular role in immunity, such that variation in their relative abundance affects the outcome of the immune response. This study aims to characterize these various types of hemocytes in larvae of the grapevine pest insect Eupoecilia ambiguella, and to assess variation in their concentration as a function of larval diet and immune challenge. Four types of hemocytes were found in the hemolymph of 5th instar larvae: granulocytes, oenocytoids, plasmatocytes and spherulocytes. We found that the total concentration of hemocytes and the concentration of each hemocyte type varied among diets and in response to the immune challenge. Irrespective of the diet, the concentration of granulocytes increased following a bacterial immune challenge, while the concentration of plasmatocytes and spherulocytes differentially varied between larval diets. The concentration of oenocytoids did not vary among diets before the immune challenge but varied between larval diets in response to the challenge. These results suggest that the resistance of insect larvae to different natural enemies critically depends on the effect of larval diet on the larvae's investment into the different types of hemocytes.
authors.affiliation: Johannes Gutenberg-Universität Mainz, Institut für Zoologie, Abt. Evolutionsbiologie, Johannes-von-Müller-Weg 6, 55128 Mainz, Germany. Electronic address: fanny.vogelweith@gmail.com.
authors.forename: Fanny
authors.initials: F
authors.lastname: Vogelweith
authors.affiliation: Université Bourgogne-Franche Comté, Équipe Écologie Évolutive, UMR 6282 Biogéosciences, 6 Bd Gabriel, F-21000 Dijon, France.
authors.forename: Yannick
authors.initials: Y
authors.lastname: Moret
authors.affiliation: Centre d'Etudes Biologiques de Chizé, UMR 7372, CNRS - Université de la Rochelle, 79360 Beauvoir-sur-Niort, France.
authors.forename: Karine
authors.initials: K
authors.lastname: Monceau
authors.affiliation: INRA, UMR 1065 Save ISVV, B.P.81, F-33883 Villenave d'Ornon Cedex, France; Université de Bordeaux, Bordeaux Sciences Agro, INRA, UMR 1065 Save ISVV, B.P.81, F-33883 Villenave d'Ornon Cedex, France.
authors.forename: Denis
authors.initials: D
authors.lastname: Thiéry
authors.affiliation: Université Bourgogne-Franche Comté, Équipe Écologie Évolutive, UMR 6282 Biogéosciences, 6 Bd Gabriel, F-21000 Dijon, France.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Moreau
mesh_terms: D000821:Animal Feed; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D006098:Granulocytes / Q000166:cytology; D006434:Hemocytes / Q000145:classification / Q000166:cytology* / Q000276:immunology; D007814:Larva / Q000166:cytology / Q000502:physiology; D009036:Moths / Q000166:cytology* / Q000276:immunology / Q000502:physiology; D027843:Vitis
keywords: Ecological immunity; Eupoecilia ambiguella; Grape varieties; Hemocyte differentiation; Lepidoptera; Tortricidae