Dispersal variability and associated population-level consequences in tree-killing bark beetles

Area of Science:

• Ecology
• Entomology
• Population Dynamics

Background:

• Insect dispersal is crucial for adapting to environmental changes.
• Individual variation in dispersal timing and distance aids population success via risk spreading.
• Studying complex, spatio-temporal dispersal interactions experimentally is challenging.

Purpose of the Study:

• Investigate the impact of individual beetle physiology (flight capacity) and host environment (susceptibility) on dispersal success.
• Analyze spatial and temporal patterns of dispersal success, host selection, and colonization density.

Main Methods:

• Utilized a local-scaled, individual-based simulation model.
• Simulated dispersal and infestation patterns in a Norway spruce - bark beetle system (Picea abies - Ips typographus).

Main Results:

• Individual variability in flight capacity generally enhances population dispersal success, particularly in resistant or scattered host habitats.
• Scattered host susceptibility is optimal for population spread, balancing success rates and spread.
• Dispersal success decreases with distance; host selectivity increases, and colonization density decreases with distance.

Conclusions:

• Individual-based models are effective for studying bark beetle movement ecology.
• Dispersal variability enhances population adaptability and risk spreading.
• Dispersal variability and environmental heterogeneity are critical factors in tree-killing bark beetle dynamics.