Microbiome-Metabolome Analyses Reveal Compound Risks from Multiple-Generation Cocoon Accumulation in Honeybee Combs

Area of Science:

• Ecology
• Microbiology
• Environmental Science

Background:

• Accumulation of cocoons in old honey bee (Apis mellifera) combs creates a microenvironment for preimaginal development.
• This accumulation can lead to enrichment of harmful microorganisms and chemical substances, threatening colony health.

Purpose of the Study:

• To investigate colony health risks from multi-generational cocoon accumulation in Apis mellifera combs.
• To analyze shifts in microbial diversity and identify specific pathogens and chemical contaminants.

Main Methods:

• Combined microbiome and metabolomics analyses.
• Assessed microbial diversity indices (Simpson, Sobs, Ace, Chao, Shannon, Pielou_e, Faith_pd).
• Identified and quantified microbial pathogens and pesticide residues.

Main Results:

• Significant shifts in bacterial and fungal diversity were observed with increasing brood generations.
• Pathogens like Melissococcus (42.70%) and Wallemia (13.52%) were enriched.
• 685 differential metabolites, including pesticides (cyanazine, pymetrozine), were identified, correlating positively with pathogen abundance.

Conclusions:

• Old comb cocoons exhibit aggravated microecological imbalance and chemical pollution.
• Comb age is a critical factor in honey bee colony health management.
• Findings provide guidance for sustainable beekeeping practices.