Metabolic and microbial changes in light-vented bulbul during recent northward range expansion

Area of Science:

• Zoology
• Microbiology
• Ecology

Background:

• Endotherms expanding into cold climates often show physiological acclimation to maintain body temperature.
• Gut microbes are crucial for host functions like digestion and thermogenesis.
• The light-vented bulbul (Pycnonotus sinensis) has recently expanded its range northward into Palearctic areas.

Purpose of the Study:

• To investigate seasonal changes in resting metabolic rate (RMR) and gut microbiota in local and newly colonized populations of the light-vented bulbul.
• To understand the relationship between gut microbial communities and host metabolic thermogenesis during northward expansion.

Main Methods:

• Collected data on resting metabolic rate (RMR) and gut microbiota composition across different latitudes and seasons.
• Analyzed correlations between RMR, body mass, and microbial community structure (alpha diversity, dominant phyla, core microbiota).

Main Results:

• Mass-adjusted RMR and body mass increased with latitude in both seasons.
• Gut microbiota composition varied with northern cold environments, showing decreased alpha diversity in northern populations.
• Significant differences in dominant bacterial phyla were observed seasonally and geographically.
• More microbial genera correlated with mass-adjusted RMR in winter (71) than in the breeding season (23).

Conclusions:

• Gut microbiota composition and diversity in the light-vented bulbul are linked to host thermogenesis.
• Microbial adaptations play a role in the species' successful northward expansion and survival in colder climates.