Simulating the effectiveness of clear-cuttings to eradicate the pine wood nematode: R script and videos

This folder contains: - the R script to simulate the dispersal of Monochamus galloprovincialis (European insect vector of the pine wood nematode, Bursaphelenchus xylophilus, from an individual-based model and to assess the effectiveness of clear-cuts of various radius (i.e., removing susceptible host trees within a given distance from a symtomatic tree); - the resulting videos of the simuations, showing the dispersal and nematode transmission in various scenarios and various clear-cut radius. We consider the following scenarios: 1) Scenario 1 (preventive scenario): the clear-cut is done before the insect dispersal. In this case, the clear-cut may affect the insect flight behavior. We consider 2 cases: the insect tends to avoid the clear-cut zone (go out and not enter again in this zone) ("avoidance strategy"), or the clear-cut zone has no effects on the insect flight behavior ("Non-avoidance strategy"). 2) Scenario 2 (curative scenario): the clear-cut is done after the insect dispersal to ensure that all infected trees (even non-symptomatic trees) are removed. In this case, there is no effect on the insect dispersal, and the infected tree initially detected may not be the source of the infected insects. In the videos, dots represent the stops of the insect, lines represent their trajectory and the circle represent the clear-cut zone. Black dots indicate that an insect stopped but not transmitted the pine wood nematode. Red dots indicate that an insect stopped and transmitted the pine wood nematode. Two video series are provided: i) Simulation of the daily dispersal and nematode transmission in case of a clear-cut of 3 km (from day 1 to 120 after the insect emergence at the adult stage), ii) Simulated spread and nematode transmission at the end of dispersal season as a function of an increasing clear-cut radius (from 0 to 40 km). Note that in these simulations, we assume that the insects disperse in a non-fragmented pine forest (i.e., host trees are not scattered in space). This study was conducted in the frame of the FP7 project called "REPHRAME", a working group of ANSES (French Agency for Food, Environmental and Occupational Health & Safety), and the H2020 project called "HOMED" (grant agreement No 771271)