Deforestation Increases Developmental Instability in the Orchid Bee Euglossa imperialis Across Protected Areas of Panama.

Habitat loss and deforestation are among the main drivers of biodiversity decline in tropical ecosystems, yet their effects on developmental stability remain poorly understood in many insect groups. Orchid bees (Apidae: Euglossini) have been proposed as potential bioindicators of environmental quality due to their close association with forested habitats and sensitivity to habitat disturbance. Here, we evaluated the relationship between forest cover, wing morphology, and developmental stability in the orchid bee Euglossa imperialis across five protected areas of Panama exhibiting different levels of deforestation. A total of 290 individuals were analyzed using geometric morphometrics and fluctuating asymmetry (FA) of the forewing. Morphological variation was assessed through Principal Component and Canonical Variate Analyses, whereas developmental instability was quantified using Procrustes ANOVA and FA scores. Wing shape showed moderate differentiation among sites, with La Tronosa, the most deforested protected area, exhibiting the greatest morphological divergence. In contrast, FA displayed a clear association with habitat degradation. La Tronosa presented the highest levels of developmental instability, and generalized linear models revealed a significant positive relationship between deforestation and FA at both local and landscape scales, with landscape-level deforestation showing the strongest effect. Our results indicate that developmental instability is more sensitive than overall wing morphology for detecting the biological consequences of habitat alteration. These findings support the use of fluctuating asymmetry as an early indicator of environmental degradation and provide new evidence for the value of orchid bees as bioindicators in tropical ecosystems.