Nectar

Nectar of camellia

An Australian painted lady feeding on a flower's nectar

Nectar is a sugar-rich liquid produced by plants. It is produced either by the flowers, in which it attracts pollinating animals, or by extrafloral nectaries, which provide a nutrient source to animal mutualists providing anti-herbivore protection. It is produced in glands called nectaries. Common nectar-consuming pollinators include bees, butterflies and moths, hummingbirds and bats.

Nectar is an economically important item, the sugar source for honey. It is also useful in agriculture and horticulture because the adult stages of some predatory insects feed on nectar.

Etymology

Nectar is derived from Latin nectar "drink of the gods," which in turn has its origins in the Greek word νέκταρ (néktar,) presumed to be a compound of the elements nek- "death" and -tar "overcoming". The earliest recorded use of its current meaning, "sweet liquid in flowers," is 1609.^[1]

Floral nectaries

Floral nectaries are generally located at the base of the perianth, so that pollinators are made to brush the flower's reproductive structures, the anthers and pistil, while accessing the nectar.

Extrafloral nectaries

Nectar produced outside the flower is generally made to attract predatory insects. These predatory insects will eat both the nectar and any plant-eating insects around, thus functioning as 'bodyguards'.^[2] Extrafloral nectaries are generally located on the leaf petioles, mid-rib or leaf margin. They are thought to be modified trichomes and exude nectar from phloem sap. Extrafloral nectaries can be found on species belonging to (amongst others) the genera Salix, Prunus and Gossypium. In many carnivorous plants, nectar serves to attract insect prey.^[3]

Extrafloral nectaries on the petiole of a Prunus avium leaf.

Extrafloral nectaries on Prunus africana

Natural components of nectar

Although its main ingredient is natural sugar (i.e., sucrose (table sugar), glucose, and fructose),^[4] nectar is a brew of many chemicals. For example, the Nicotiana attenuata, a tobacco plant native to the US state of Utah, uses several volatile aromas to attract pollinating birds and moths. The strongest such aroma is benzyl acetone, but the plant also adds bitter nicotine, which is less aromatic and therefore may not be detected by the bird until after taking a drink. Researchers speculate the purpose of this addition is to drive the bird away after only a sip, motivating it to visit other plants to fill its hunger, and therefore maximizing the pollination efficiency gained by the plant for a minimum nectar output.^[5] Neurotoxins such as aesculin are present in some nectars such as that of the California Buckeye.^[6]

Other uses of the word

Nectar is a name commonly given to drinks manufactured with fruit juice (e.g. mango nectar, pear nectar, peach nectar).

See also

• Nectar source
• Nectar guide
• Nectarivore
• Northern nectar sources for honey bees

References

External links

• Nectar Plants Database