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Honeydew (secretion)

An aphid produces honeydew for an ant in an example of mutualistic symbiosis
Honeydew drops on leaves
Honeydew puddle under a tree

Honeydew is a sugar-rich sticky liquid, secreted by aphids and some scale insects as they feed on plant sap. When their mouthpart penetrates the phloem, the sugary, high-pressure liquid is forced out of the anus of the aphid. Honeydew is particularly common as a secretion in hemipteran insects and is often the basis for trophobiosis.[1] Some caterpillars of Lycaenidae butterflies and some moths also produce honeydew.[2]

Honeydew producing insects like cicadas pierce phloem ducts to access the sugar rich sap. The sap continues to bleed after the insects have moved on leaving a white sugar crust called manna.[3] Ants may collect, or "milk", honeydew directly from aphids and other honeydew producers, which benefit from their presence due to their driving away predators such as lady beetles or parasitic wasps—see Crematogaster peringueyi. Animals and plants in a mutually symbiotic arrangement with ants are called Myrmecophiles.

In Madagascar, some gecko species in the genera Phelsuma and Lygodactylus are known to approach flatid plant-hoppers on tree-trunks from below and induce them to excrete honeydew by head nodding behaviour. The plant-hopper then raises its abdomen and excretes a drop of honeydew almost right onto the snout of the gecko.[4]

Honeydew can cause sooty mold—a bane of gardeners—on many ornamental plants. It also contaminates vehicles parked beneath trees, and can then be difficult to remove from glass and bodywork. Honeydew is also secreted by certain fungi, particularly ergot.[5] Honeydew is collected by certain species of birds, wasps, stingless bees[6] and honey bees, which process it into a dark, strong honey (honeydew honey). This is highly prized in parts of Europe and Asia for its reputed medicinal value. Parachartergus fraternus, a eusocial wasp species, collects honeydew to feed to their growing larvae.[7] Recent research has also documented the use of honeydew by over 40 species of wild, native, mostly solitary bees in California.[8]

Religion and mythologyEdit

In Norse mythology, dew falls from the ash tree Yggdrasil to the earth, and according to the Prose Edda book Gylfaginning, "this is what people call honeydew and from it bees feed."[9]

In Greek mythology, méli, or "honey", drips from the Manna–ash, (Fraxinus ornus), with which the Meliae, or "ash tree nymphs", nursed the infant god Zeus on the island of Crete,[10] (as in the Hymn to Zeus by Callimachus).

Honey-dew is referenced in the last lines of Samuel Coleridge's poem Kubla Khan, perhaps because of its mythological connotations:

And all who heard should see them there,
And all should cry, Beware! Beware!
His flashing eyes, his floating hair!
Weave a circle round him thrice,
And close your eyes with holy dread,
For he on honey-dew hath fed,
And drunk the milk of Paradise.

In the Hebrew Bible, while the Israelites are wandering through the desert after the Exodus, they are miraculously provided with a substance, manna, that is sometimes associated with honeydew.[11] Exodus 16:31 provides a description: "it was like coriander seed, white, and the taste of it was like wafers made with honey."

Nectar producing treesEdit


In eucalypt forests, production of both the honeydew nectar and manna tends to increase in spring and autumn. Eucalyptus can produce even more manna than honeydew nectar. The sugar glider possum eats both, licking the nectar from branches. Other species attracted to the nectar include the feathertail glider, brush-tailed phascogale, and brown antechinus. Most trees are not able to produce sap if the phloem duct becomes damaged by mechanical processes.[3]


The Ommatissus lybicus is attracted to certain cultivars of the date palm tree. The honeydew producing insects preferred the Medjhool variety to the Deglet Noor in Israel, where they have been observed in the Arava Valley. Very dense insect populations may have some adverse effects. Different methods of controlling the insects, including natural and chemical, have been studied.[12]


Two scale insects in the Sinai, Trabutina mannipara and Najacoccus serpentinus feed on Tamarisk trees. They secrete a sugary nectar that turns white when it hardens, resembling certain whitish flakes described in the Hebrew scriptures.[13]

See alsoEdit


  1. ^ Delabie, JHC (2001) Trophobiosis Between Formicidae and Hemiptera (Sternorrhyncha and Auchenorrhyncha): an Overview. Neotropical Entomology 30(4):501-516 PDF
  2. ^ Maschwitz U, Dumpert K, Tuck KR (1986). "Ants feeding on anal exudate from tortricid larvae: a new type of trophobiosis". Journal of Natural History. 20 (5): 1041–1050. doi:10.1080/00222938600770751.
  3. ^ a b Lee, Anthony K. Evolutionary Ecology of Marsupials. Cambridge University Press. p. 33. Retrieved 25 August 2019.
  4. ^ Foelling, M; C Knogge; W Bohme. "Geckos are milking honeydew-producing planthoppers in Madagascar". J. Nat. Hist. 2001: 279–284.
  5. ^ Ergot of Rye,, The American Phytopathological Society
  6. ^ Koch, H.; Corcoran, C.; Jonker, M. (2011). "Honeydew Collecting in Malagasy Stingless Bees (Hymenoptera: Apidae: Meliponini) and Observations on Competition with Invasive Ants" (PDF). African Entomology. 19 (1): 36–41. doi:10.4001/003.019.0111. Archived from the original (PDF) on 2012-03-19.  
  7. ^ Mateus, Sidnei, Fernando Barbosa Noll, and Ronaldo Zucchi. "Caste Flexibility and Variation According to the Colony Cycle in the Swarm-founding Wasp, Parachartergus Fraternus (Gribodo) (Hymenoptera: Vespidae: Epiponini)". Journal of the Kansas Entomological Society 77.4 (2004): 470–83. Web. 11 Oct. 2014.
  8. ^ Meiners, Joan M.; Griswold, Terry L.; Harris, David J.; Ernest, S. K. Morgan (2017-05-22). "Bees without Flowers: Before Peak Bloom, Diverse Native Bees Find Insect-Produced Honeydew Sugars". The American Naturalist. 190 (2): 281–291. doi:10.1086/692437. ISSN 0003-0147.
  9. ^ Faulkes, Anthony (Trans.) (1995). Edda. Everyman. ISBN 0-460-87616-3 pp18–19
  10. ^ Clauss, James Joseph (1993). The Best of the Argonauts: The Redefinition of the Epic Hero in Book 1 of Apollonius's Argonautica. Hellenistic culture and society. 10. University of California Press. p. 170. ISBN 978-0-520-07925-0.
  11. ^ Manna#Identifying manna
  12. ^ Howard, F. W. Insects on Palms. p. 154. Retrieved 25 August 2019.
  13. ^ Jolivet, Pierre (1992). Insects and Plants: Parallel Evolution & Adaptations, Second Edition. Sandhill Crane Press. p. 119. Retrieved 25 August 2019.