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Trees wanted--dead or alive! Host selection and population dynamics in tree-killing bark beetles
Kyrre L Kausrud1, Jean-Claude Grégoire, Olav Skarpaas
1Department of Biology, Centre for Ecological and Evolutionary Synthesis, University of Oslo, Oslo, Norway.
Plos One
|June 8, 2011
Summary
Bark beetles can overcome tree defenses through risky mass attacks. This behavior, influenced by population density and environmental changes, can lead to spontaneous forest epidemics.
Area of Science:
- Ecology
- Forestry
- Entomology
Background:
- Bark beetles (Coleoptera: Curculionidae, Scolytinae) typically infest weakened trees.
- High beetle populations can lead to mass attacks on healthy trees, overwhelming defenses and causing tree mortality.
Purpose of the Study:
- Investigate the adaptive conditions for conspecifics engaging in risky mass attacks on living trees.
- Understand the drivers of bark beetle outbreak dynamics and tree-killing behavior.
Main Methods:
- Modeling individual host selection strategies.
- Analyzing the emergence of aggressive behavior and its heritability.
- Comparing model predictions with empirical observations of bark beetle populations.
Main Results:
- Individual host selection can deviate from ideal free distribution, promoting tree-killing behavior.
- Aggressiveness traits may exhibit cyclical heritability, mirroring natural population variability.
- Bark beetle population dynamics can spontaneously shift between endemic and epidemic states.
Conclusions:
- Understanding individual bark beetle behavior is key to predicting outbreak dynamics.
- Environmental changes, such as climate and forest structure, can influence beetle epidemics.
- Factors influencing epidemic occurrence and self-limitation were identified.
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