Phytogeographic regions and geographic distance do not predict genetic structure in the orchid bee Euglossa cordata

Abstract

Herein, we investigated the genetic diversity and population structure of Euglossa cordata L., an orchid bee species widely distributed at the heterogeneous set of vegetal physiognomies encompassed in a transition zone (TZ) of different Brazilian biomes. We then tested whether phytogeographic regions would play some rule for the genetic diversity. Results revealed that only 12 and 28 out 78 pairs of samples showed some degree of genetic structure for microsatellites (F ST≤ 0.029; Dest ≤0.091; p < 0.05) and mtDNA(0.138 ≤mt-ϕST≤ 0.495; p < 0.05) markers, respectively. We found evidence of two and three genetic clusters in nuclear and mtDNA markers, but no significant structure based on phytogeographic regions or geographic distances. These findings point out that local idiosyncrasies and historic factors, but not different types of vegetation or geographic distances drive the patterns of the observed genetic structure. Drops in the diversity index and other estimators highlight that E. cordata may have experienced some local bottlenecks despite its resilience to anthropic interferences. These are the first records of relatively high genetic structure in E. cordata populations and have important implications for orchid bees’ conservation.