Precipitation and molecular form. Correlation between the proportion of M molecular forms and the average annual precipitation in (A) Cameroon and (B) Mali. Average annual precipitation was calculated using annual precipitation at multiple weather stations at or near collection sites (within a 15 km radius) and over multiple years. ○ = average annual precipitation at each site. Details of precipitation data are provided in Table S2. A. The proportion of the M forms increases as precipitation increases in Cameroon. B. The opposite trend was observed in Mali. These seemingly conflicting results illustrate that the Forest-M form and Mopti-M form differ with respect to habitat preference as well as being differentiated genetically. The solid line is a linear model (y~ax+b) of the data. (A) For the Cameroon data, a = 0.0395 ± 0.0184 (P = 0.121) and b = -50.5 ± 37.8 (P = 0.274). (B) For the Mali data, a = -0.108 ± 0.0150 (P = 0.00197) and b = 122 ± 10.3 (P = 0.000283).