Lu. longipalpis s.l . across the Brazilian NE region. Shown is the Sao Francisco River in its current course (A), and prior to the Pleistocene period (B). (A) Lu. longipalpis s.l. used in this study were sampled from various locations across the Brazilian NE (numbers 1–8) and from a single location in the SE (number 9); a, indicates the population in Sobral, Ceara, where two distinct male sexual pheromones (9MGB+ and cembrene-1) are found in sympatry; grey arrow indicates a secondary contact between Lu. longipalpis s.l. in Sobral, as suggested by . According to our results we propose that this secondary contact took place following the course change of the Sao Francisco River. Gray dots (appearing in northerly direction) represent the old course of the Sao Francisco. (B) Original south-to-north course of the Sao Francisco River, with the distribution of the various known Lu. longipalpis s.l. male sexual pheromones (a-h); Arrowhead indicates expansion of Lu. longipalpis s.l. towards the NE region based on sub-Andean/Amazonian gene pool expansion ; Grey lines depicts a model for expansion of Lu. longipalpis s.l. populations towards SE and NE areas during the Pliocene-Pleistocene period, using the Sao Francisco River as a geographic barrier. Horizontal dashed gray lines represent the 10°S parallel.