Problem SE1

Scientists want to measure the diffusion ability into the surrounding environment of the genetically modified predator insect Typhlodromus vorax. It attacks the larvae of Eotetranychus octomaculatus, a defoliator that likes apple trees very much. For environmental safety, the GMO has been made sterile. 1,000 individuals of the species T. vorax are released in an experimental garden . In the following two months the expansion radii of the GMO in the garden are monitored and recorded:

Day	1	4	8	13	20	35	45	60
Radius (metres)	5	12	16	21	26	34	39	45

Estimate the diffusion coefficient of T. vorax assuming that mortality during the two months is negligible and that scientist cannot find 5% of the population outside the expansion radius.