Figure 1.

Male (part A) and female (part B) body size frequency distributions. In the upper part of A and B: Guérande canal populations (black solid line; Pogonus chalceus), pond populations (black dotted line; Pogonus chalceus) and Pogonus littoralis populations (gray dashed line). In the lower part of A and B: European stable populations (P. chalceus; black solid line), intermediate populations (P. chalceus; black dotted line), temporary Atlantic and Mediterranean populations (gray filled; P. chalceus) and Pogonus littoralis populations (gray dashed line). Figure legend text.