Table 1 Model input parameters for beetles and trees
From: Dispersal variability and associated population-level consequences in tree-killing bark beetles
| Parameter | Values | Unit | Description | References | |
|---|---|---|---|---|---|
| Beetle | Energy level | 10 | abstract unit | Energy supplies at the start of dispersal; chosen randomly for each individual from a Gaussian distribution N (μ, 2), where μ is the used value 10; linearly reduced during flight by a constant consumption value, which is defined by the individual efficiency | [42, 43] |
| Efficiency | 20 | abstract unit | Determines energy consumption per movement step, (consumption = 1/efficiency); chosen randomly for each individual from an exponential distribution Exp (λ), where 1/λ is the used value 20 | [44] | |
| Perceptual range | 15 | meter | Radius in which an individual senses attractiveness; constant for all individuals of a dispersing population | [21, 40] | |
| Moving angle | 45 | degree | Angle of movement to neighbouring trees, related to previous movement (correlated random walk); chosen randomly in every time step for each individual from a defined sector (±45°) | [21, 41] | |
| Starting beetles | 10,000 | − |
Number of beetles starting simultaneously (= flight cohort size) | - | |
| Total beetles | 100,000 | − |
Total number of dispersing individuals (= source size) corresponding to a group of approx. 5 source trees | [43, 82] | |
| Time lag | 10 | time steps | Time lag between subsequent flight cohorts | - | |
| Host | Primary attractiveness | 0 − 9 | abstract unit | Kairomone-induced primary attractiveness, ranging from 0 (no attractiveness) to 9 (highest attractiveness); chosen randomly from a habitat-specific range; inverse to the resistance to beetle attacks | [14, 83] |
| Capacity limit | 5,000 | − | Maximum number of beetles infesting a host | [49] |