Genetic and phenotypic differentiation in endemic Scaptotrigona hellwegeri (Apidae: Meliponini): implications for the conservation of stingless bee populations in contrasting environments

The western forests of Mexico are rich in species of stingless bee, possi- bly a consequence of the diverse habitats found across different altitudes of the Trans-Mexican Volcanic Belt (TMVB) and the Pacific coast (PAC). 2. Scaptotrigona hellwegeri is an example of a stingless bee species found across the TMVB and PAC. It is currently considered a single species. Its TMVB popula- tions have become rare and rapidly impacted by human-modified habitats. Translo- cation of S. hellwegeri colonies from the PAC tropical lowlands to TMVB subtropical highlands has been considered, as colonies at PAC are more abundant and even used in stingless beekeeping. 3. Morphometric analyses of meristic characters plus genetic analysis at microsat- ellite loci and sequencing of the cox1 region of mtDNA were used to evaluate pheno- typic and genetic differentiation in S. hellwegeri from TMVB and PAC. 4. Significant morphometric differences were detected between S. hellwegeri from TMVB and PAC. Corrected nuclear multilocus F¢ST was 0.592 (P < 0.01), support- ing the view that TMVB and PAC populations are markedly genetically differenti- ated. A 573 bp sequence of the cox1 region of mtDNA showed six sites of divergence, with sequence divergence between PAC and TMVB populations of 1.1%. 5. Our morphometric and genetic results make evident that S. hellwegeri from TMVB and PAC are significantly differentiated and represent two genetic lineages. An immediate recommendation is to restrict the movement of colonies from the low- land PAC regions to TMVB, where colonies are currently scarce.