Early suppression of immune response in Heliothis virescens larvae by the endophagous parasitoid Toxoneuron nigriceps

Authors

  • R Ferrarese Department of Structural and Functional Biology, University of Insubria, Varese, Italy
  • M Brivio Department of Structural and Functional Biology, University of Insubria, Varese, Italy
  • T Congiu Department of Human Morphology, University of Insubria, Italy
  • P Falabella Dipartimento di Biologia, Difesa e Biotecnologie Agro-Forestali, Università della Basilicata, Potenza, Italy
  • A Grimaldi Department of Structural and Functional Biology, University of Insubria, Varese, Italy
  • M Mastore Department of Structural and Functional Biology, University of Insubria, Varese, Italy
  • G Perletti Department of Structural and Functional Biology, University of Insubria, Busto Arsizio, Italy
  • F Pennacchio Dipartimento di Biologia, Difesa e Biotecnologie Agro-Forestali, Università della Basilicata, Potenza, Italy
  • L Sciacca Department of Structural and Functional Biology, University of Insubria, Varese, Italy
  • G Tettamanti Department of Structural and Functional Biology, University of Insubria, Varese, Italy
  • R Valvassori Department of Structural and Functional Biology, University of Insubria, Varese, Italy
  • M de Eguileor Department of Structural and Functional Biology, University of Insubria, Varese, Italy

Keywords:

insects, parasitoid, immune defenses

Abstract

Toxoneuron nigriceps is an endophagous parasitoid of larval stages of the noctuid moth Heliothis
virescens. As all parasitoids, this wasp avoid host immune reaction by a combination of several passive
and active mechanisms. Secretions injected by ovipositing females, which contain venom, calyx fluid and polydnaviruses, are the most probably factors actively disrupting Heliothis virescens immune system. This paper describes the main alterations of the host immune response observed shortly after oviposition by T. nigriceps. A transient block of prophenoloxidase activity is registered along with changes in hemocyte number, adhesion and structure, which suggest the occurrence of apoptosis. In contrast, the host plasmatocytes appear structurally unaltered, but unable to produce a capsule in vitro.

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Published

2005-04-28

Issue

Vol. 2 No. 1 (2005)

Section

Research Reports