Byers, J.A. 1992. Dirichlet tessellation of bark beetle
spatial attack points. Journal of Animal Ecology
(1) Algorithms for Dirichlet tessellation of spatial points are developed and
implemented on personal computer. Up to 3000 tessellations of points in an area
of any rectangular dimensions can be scaled appropriately and viewed on computer
screen or output to laser printer.
(2) The program also calculates Dirichlet cell areas and their coefficient of
variation (CV) as well as the average nearest neighbour distance between points.
(3) Simulations revealed the polynomial relationship between the CV and the
minimum spacing between points. The relationship is used to predict the
percentage of maximum spacing that is exhibited by a population. This value
times the maximum spacing distance possible between objects in an area
(hexagonal arrangement) yields the minimum allowed distance (MAD) that is
characteristic of individuals of some territorial or `inhibitive' species.
(4) The program and relationship were used to analyze the spatial attack
patterns of the bark beetles, Dendroctonus brevicomis LeConte,
Tomicus piniperda (L.), and Pityogenes chalcographus (L.) and determine their
MAD's. All three species exhibited spacing between attack sites, in agreement
with known behavioural mechanisms that are proposed for avoiding intraspecific
competition for food resources.
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