Caterpillar-parasitoid interactions: species-specific influences on host microbiome composition

Area of Science:

• Insect microbiology
• Host-parasitoid interactions
• Microbial ecology

Background:

• Host-parasitoid interactions can significantly impact insect microbiomes.
• The specific contributions of the host and parasitoid to these microbiome changes are not fully understood.

Purpose of the Study:

• To compare the internal and external microbiomes of parasitized and non-parasitized caterpillars (Pieris brassicae and Pieris rapae).
• To investigate the microbiomes of parasitoid larvae (Cotesia glomerata and Cotesia rubecula).
• To determine how host and parasitoid species influence microbiome composition during parasitism.

Main Methods:

• Comparative analysis of internal and external microbiomes in caterpillars and parasitoid larvae.
• Microbial density assessments and composition analysis.
• Identification of specific microbial species (e.g., Wolbachia, Nosema).

Main Results:

• Bacterial densities were higher in P. brassicae than P. rapae, but not affected by parasitism status.
• Parasitism significantly altered microbiome composition in both caterpillars and parasitoids, with species-specific effects.
• Wolbachia was found in C. glomerata-parasitized hosts and larvae; Nosema was prevalent in parasitized hosts and larvae, irrespective of species.

Conclusions:

• Parasitism profoundly affects host insect microbiomes.
• The impact of parasitism on insect microbiomes is dependent on the specific host and parasitoid species involved.
• Specific microbes like Wolbachia and Nosema can be shared between hosts and their parasitoids.