Heterogeneity in infection outcome: lessons from a bumblebee-trypanosome system

Area of Science:

• Ecology
• Evolutionary Biology
• Immunology

Background:

• Host-parasite interactions are crucial due to shared relevance in human and utilized species.
• Insect host-parasite dynamics exhibit heterogeneity in infection success, load, virulence, and transmission.
• Environmental factors significantly influence infection outcomes, impacting host and parasite evolution.

Purpose of the Study:

• To synthesize research on bumblebee immunity and parasite interactions, focusing on Crithidia.
• To explore sources of heterogeneity in host-parasite systems, applicable to human-relevant contexts.
• To discuss the roles of genotypic variation, environment, and microbiota in modulating host defense.

Main Methods:

• Review and synthesis of existing literature on bumblebee-Crithidia interactions.
• Analysis of evolutionary ecology studies on natural variation in host-parasite systems.
• Examination of factors contributing to heterogeneity in infection outcomes.

Main Results:

• Bumblebee-Crithidia system highlights significant heterogeneity in infection dynamics.
• Genotypic variation in hosts and parasites contributes to varied infection outcomes.
• Environmental factors and host microbiota play critical roles in modulating parasite defense.

Conclusions:

• Comprehending the host-parasite-environment triad is essential for understanding infection dynamics.
• Natural variation studies offer insights into heterogeneity, relevant for broader epidemiological research.
• Microbiota modulation of defense presents a key area for future investigation in insect-parasite interactions.