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ARS Home » Southeast Area » Tifton, Georgia » Crop Genetics and Breeding Research » Research » Publications at this Location » Publication #430809
Research Project: Genetic Improvement and Management of Warm-Season Forage, Feedstocks, Syrup, and Turf Grasses

Location: Crop Genetics and Breeding Research

Title: Extrafloral nectaries on Cenchrus americanus (L.). Morrone

Author
item Harris-Shultz, Karen
item Knoll, Joseph
item KOEHNE, HUTTON - Keyence Corporation Of America
item Faustinelli, Paola

Submitted to: Agricultural & Environmental Letters
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/5/2026
Publication Date: N/A
Citation: N/A

Interpretive Summary: Pearl millet is grown for its grain and for forage and its pollen is a food source especially for bees, earwigs, and hover flies. In August of 2023, over multiple days, large numbers of honey bees and wasps were observed near the nodes of an acre of Tift Long-Headed bulk (a cultivar of pearl millet) but no one knew why. In 2025, a population of pearl millet was grown in the greenhouse and found to be secreting extrafloral nectar from these nodal areas. The extrafloral nectar was collected and found to be composed of sugars, primarily sucrose but also glucose and fructose, as well as protein. Magnification of hairs on the auricle revealed the presence of multicellular hairs with rounded bases. We suggest that these rounded structures secrete nectar which drip from the auricle down onto the culm and leaf sheath and thus attract insects. Our findings show that pearl millet not only provides pollen but also nectar which is quite rare in grasses.

Technical Abstract: Pearl millet, used for food and feed, has pollen that attracts multiple insect species. In 2023 honey bees and wasps were observed foraging on or below the auricles of pearl millet in a Georgia field. In 2025, pearl millet was grown in a greenhouse and found to be secreting extrafloral nectar. This extrafloral nectar was collected and found to be composed of sugars, primarily sucrose but also glucose and fructose, as well as protein. Nectar droplets were seen at the tips of the auricle hairs, on the culm, and leaf sheaths. Large amounts of extrafloral nectar accumulated just below the auricle. Magnification of hairs on the auricle revealed the presence of multicellular hairs with bulbous bases. We conjecture that these bulbous structures secrete nectar which drip from the auricle down onto the culm and leaf sheath. Thus, we report the discovery that pearl millet not only provides pollen for insects but also nectar.