A dual pollination strategy combining perfume attraction and food deception in Galeandra blanchetii E.S. Rand...

The evolutionary origin of the perfume flower syndrome remains unclear. Orchids of the subtribe Catasetinae help elucidate the evolution of this syndrome, but knowledge gaps regarding the pollination biology of Galeandra hinder a full understanding of the process. This study addresses this gap by investigating G. blanchetii, an epiphytic Catasetinae species endemic to Brazil. We explored its floral and reproductive biology, including floral anatomy, scent characterization and pollinator mechanical fit, to clarify the role of floral signals in pollinator attraction. We found epidermal osmophores and unicellular glandular trichomes in the labellum, but no nectar production was detected. Floral scent comprised 34 compounds, with methyl salicylate and methyl benzoate as the most abundant constituents. Despite being self-compatible, G. blanchetii requires biotic vectors for reproduction. The flowers attracted both male and female bees; however, only some male Euglossini bees exhibited fragrance-collecting behaviour, whereas females were observed only searching for nectar. Pollinaria were removed only when bees entered the spur while searching for nectar, indicating that fragrance collection alone did not result in pollination. We conclude that G. blanchetii exhibits a dual pollination strategy combining perfume attraction and food deception. Floral fragrance provides a resource for male Euglossini bees, whereas melittophilous floral traits and the absence of nectar are consistent with food deception in floral visitors searching for nectar. This combination provides further insights into the diversity and evolution of pollination strategies within Galeandra and, more broadly, within Catasetinae.