Organ-specific volatiles from Sonoran desert Krameria flowers as potential signals for oil-collecting bees.

Autor: Balbuena MS; Department of Neurobiology and Behavior, Cornell University, Ithaca, NY, 14853, USA. Electronic address: msbalbuena@agro.uba.ar., Buchmann SL; Department of Entomology, University of Arizona, Tucson, AZ, 85721, USA; Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, 85721, USA. Electronic address: buchmann.stephen@gmail.com., Papaj DR; Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, 85721, USA. Electronic address: papaj@arizona.edu., Raguso RA; Department of Neurobiology and Behavior, Cornell University, Ithaca, NY, 14853, USA. Electronic address: rar229@cornell.edu.
Jazyk: angličtina
Zdroj: Phytochemistry [Phytochemistry] 2024 Feb; Vol. 218, pp. 113937. Date of Electronic Publication: 2023 Nov 28.
DOI: 10.1016/j.phytochem.2023.113937
Abstrakt: The evolution of flowers that offer oils as rewards and are pollinated by specialized bees represents a distinctive theme in plant-pollinator co-diversification. Some plants that offer acetylated glycerols as floral oils emit diacetin, a volatile by-product of oil metabolism, which is utilized by oil-collecting bees as an index signal for the presence of floral oil. However, floral oils in the genus Krameria (Krameriaceae) contain β-acetoxy-substituted fatty acids instead of acetylated glycerols, making them unlikely to emit diacetin as an oil-bee attractant. We analyzed floral headspace composition from K. bicolor and K. erecta, native to the Sonoran Desert of southwestern North America, in search of alternative candidates for volatile index signals. Using solid-phase microextraction, combined with gas chromatography-mass spectrometry, we identified 26 and 45 floral volatiles, respectively, from whole flowers and dissected flower parts of these two Krameria species. As expected, diacetin was not detected. Instead, β-ionone emerged as a strong candidate for an index signal, as it was uniquely present in dissected oil-producing floral tissues (elaiophores) of K. bicolor, as well as the larval cells and provisions from its oil-bee pollinator, Centris cockerelli. This finding suggests that the floral oil of K. bicolor is perfused with β-ionone in its tissue of origin and retains the distinctive raspberry-like scent of this volatile after being harvested by C. cockerelli bees. In contrast, the elaiophores of K. erecta, which are not thought to be pollinated by C. cockerelli, produced a blend of anise-related oxygenated aromatics not found in the elaiophores of K. bicolor. Our findings suggest that β-ionone has the potential to impact oil-foraging by C. cockerelli bees through several potential mechanisms, including larval imprinting on scented provisions or innate or learned preferences by foraging adults.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2023 Elsevier Ltd. All rights reserved.)
Databáze: MEDLINE
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