Vertical stratification in orchid bees (Apidae: Euglossini)?: a meta-analysis

Abstract

Vertical stratification of animal assemblages has been observed in several arthropod taxa. However, for some groups there is conflicting evidence, such as for the neotropical orchid bees. Here, we used a meta-analysis to evaluate trends in abundance and diversity of euglossine bees across strata. We found no evidence of stratification in terms of diversity, but abundance was higher in the understory. Our results highlight the effect of sampling technique as a source of heterogeneity. For instance, studies that used McPhail traps reported higher diversity, higher similarity between strata, and were more accurate for quantifying abundance, as compared to improvised traps. Studies that used higher number of bait types sampled higher diversity in general. The higher abundance in the understory tended to decrease with the number of bait types used. Variables like elevation and latitude of the study influenced bees’ distribution. We also discuss other influential variables, ecological implications, and recommend areas for future research.