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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]