Decline of native bees (Apidae:Euglossa) in a tropical forest of Panama

We measured abundance, diversity, and richness ofEuglossabees (Euglossini, Apidae) in lowland semi-deciduous forest in Darien National Park, Panama, during the wet and dry seasons in the canopy and understory for five consecutive years (2013 to 2017) using McPhail traps baited with eucalyptus oil. We found a precipitous decline in abundance and richness throughout the 5 years of our study. Alpha diversity also declined throughout the study. Abundance, species richness and alpha diversity were significantly higher in the dry than in the wet season. There were no significant differences in the diversity, richness, or abundance between the canopy and understory. Our data contrast sharply with previous long-term studies of euglossine bees which showed stable populations.