Detection of Nosema ceranae in Euglossa imperialis (Apidae) and a synthesis of host associations across Hymenoptera.

Pathogen spillover from managed to wild pollinators represents an emerging threat to global pollinator diversity. However, surveillance of microbial pathogens in tropical wild bee communities remains severely limited. We investigated Nosema ceranae detection prevalence in the orchid bee Euglossa imperialis across seasons at 2 ecologically contrasting sites in the Panama Canal corridor: a protected tropical forest and a semi-urban landscape. Using species-specific polymerase chain reaction (PCR) assays, we detected N. ceranae DNA in gut tissues of this euglossine bee. Detection prevalence was significantly higher at the protected forest site (34/44; 77.3%) than at the semi-urban site (12/38; 31.6%), with no seasonal effect observed. A literature synthesis revealed that Nosema parasites have been reported across at least 9 hymenopteran families, with N. ceranae showing the broadest distribution of reported associations among named species, including detections in managed and wild bees as well as social wasps. This study provides the first molecular detection of N. ceranae in E. imperialis and indicates that N. ceranae DNA is detectable in wild pollinator communities at 2 ecologically contrasting sites in the Panama Canal corridor. The higher detection prevalence at the forest site suggests that local spatial or ecological context may be an important correlate of exposure in this system, a hypothesis that will require testing with additional replicated sites and environmental covariates. These findings highlight the need for expanded pathogen monitoring in Neotropical pollinator communities and underscore the importance of integrating ecological surveillance with molecular diagnostics to assess emerging pathogen risks in tropical ecosystems.