Avian use of honeydew (Hemiptera: Coccoidea) in the Atlantic Forest of Southeastern Brazil

Abstract Honeydew is a carbohydrate-rich exudate produced by scale insects (Hemiptera) that feed on phloem sap and excrete surplus sugars. Although its consumption by birds has been documented in a few tropical and temperate systems, its ecological relevance remains underexplored. Here, we describe the use of honeydew produced by Stigmacoccus paranaenses (Stigmacoccidae) on Inga trees (Fabaceae) by birds in the Atlantic Forest of southeastern Brazil. From March to October 2017, we conducted 359 hours of full-day observations and recorded 2599 visits from 25 bird species. Visitation was dominated by nectarivorous and frugivorous species, especially Coereba flaveola , Thalurania glaucopis , and Thraupis ornata , which together accounted for over 75% of visits. Generalised linear mixed models indicated strong seasonal variation in visitation rates, with peaks during the dry season (April–July) and a decline during wetter months. In contrast, no significant effects were found for time of day, honeydew sugar concentration, or air temperature. Species richness of visitors was also higher during the dry season. These findings suggest that honeydew may serve as a seasonal fallback resource for birds with high energetic demands, reinforcing its potential ecological role in fragmented tropical landscapes. From a restoration perspective, the presence of native plant species that host honeydew-producing insects, such as Inga , may enhance trophic complexity and support bird foraging during periods of resource scarcity, contributing to the ecological resilience of restored Atlantic Forest landscapes.