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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]
  1. Table modified from [33]