Exploring the Niche Concept in a Simple Metaorganism

Area of Science:

• Microbiology
• Ecology
• Evolutionary Biology

Background:

• Organisms and their resident microbial communities (microbiome) form complex ecosystems.
• Microbiome composition significantly impacts host health and fitness, but assembly processes are poorly understood.

Purpose of the Study:

• To investigate microbial community assembly and structure in the simple metaorganism Hydra.
• To apply niche and trait-based approaches to understand microbiome patterns.

Main Methods:

• Utilized niche theory and trait-based approaches.
• Analyzed microbial community structure in Hydra associations.

Main Results:

• Carrying capacities in single associations differed from microbiota densities in communities, indicating a fundamental vs. realized niche discrepancy.
• Two main bacterial colonizers, Curvibacter sp. and Duganella sp., benefited from association with other microbiome members, achieving higher abundances.
• This benefit was not linked to host interaction traits or specific nutrient utilization but likely resulted from inter-bacterial metabolic interactions.

Conclusions:

• Microbial community assembly in Hydra is influenced by inter-species metabolic interactions rather than solely host-related traits.
• The findings highlight the importance of considering metabolic cross-feeding in understanding microbiome dynamics and host-microbe interactions.