Toxic Factor Produced by a Granulosis Virus in Armyworm Larva: Effect on Apanteles militaris

Area of Science:

• Insect pathology
• Entomology
• Virology

Background:

• The armyworm larva (Spodoptera exempta) is a significant agricultural pest.
• Internal parasitoids, such as Apanteles militaris, are natural enemies of insect pests.
• Viral infections can alter host physiology and immune responses, potentially affecting interactions with natural enemies.

Purpose of the Study:

• To investigate the toxic effects of granulosis virus-infected armyworm hemolymph on the parasitoid Apanteles militaris.
• To determine if the toxicity is associated with viral particles or other hemolymph components.

Main Methods:

• Collection of hemolymph from armyworm larvae infected with granulosis virus.
• Centrifugation of hemolymph to remove virus particles.
• Intrahemocoelic inoculation of treated and untreated hemolymph into parasitoids.
• Observation of parasitoid survival and toxicity symptoms.

Main Results:

• Hemolymph from virus-infected larvae exhibited toxicity towards Apanteles militaris.
• Toxicity remained significant even after centrifugation, indicating the presence of a non-particulate toxic factor.
• The toxic factor is suggested to be proteinaceous in nature.

Conclusions:

• A proteinaceous toxic factor in the hemolymph of granulosis virus-infected armyworm larvae negatively impacts the survival of the parasitoid Apanteles militaris.
• This factor contributes to the complex interactions between host-pathogen and host-parasitoid systems.
• Understanding these interactions is crucial for biological control strategies.