Long description

This figure comprises three scatter graphs showing the distance from the Mediterranean coast plotted against frequency of the ester1 allele (blue data) and the ester4 allele (red data) in mosquito populations in the south of France for three dates between 1986 and 1996. In each case the vertical axis is labelled frequency of the ester allele and is marked from zero to 1.0 with intervals every 0.20. The horizontal axis is labelled distance from the coast/km and is marked from zero to 50 with intervals every 10 km. A curve is drawn through the numerous data points.

(a) The graph on the left shows the data taken in 1986. At the coast, the frequency of the ester1 allele is just above 0.6 which steadily declines to almost zero by 50 km from the coast. For the ester4 allele, the frequency at the coast is just above zero and slowly increases to 0.1 by ~45 km from the coast.

(b) The graph in the middle shows the data taken in 1993. At the coast, the frequency of the ester1 allele is just above 0.2 and steadily declines to 0.1 by 50 km from the coast. For the ester4 allele, the frequency at the coast is just above 0.2 and increases to 0.5 by ~50 km from the coast.

The graph on the right shows the data taken in 1996. At the coast, the frequency of the ester1 allele is 0.1 and steadily declines to ~0.05 by 50 km from the coast. For the ester4 allele, the frequency at the coast is just above 0.5 and decreases to just above 0.4 by ~50 km from the coast.