Cornicle

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Aphid excreting defensive fluid from the cornicles

The cornicle (or siphuncule) is one of a pair of small upright backward-pointing tubes found on the dorsal side of the last segment of the bodies of aphids. They are sometimes mistaken for cerci. They are no more than pores in some species.

These abdominal tubes exude droplets of a quick-hardening defensive fluid[1] containing triacylglycerols called cornicle wax. There is some confusion in the literature about the function of the cornicle wax secretions. It was common at one time to suggest that the cornicles were the source of the honeydew, and this was even included in the Shorter Oxford English Dictionary[2] and even appears in the 2008 edition of the World Book Encyclopedia.[3] There also is documentation in the literature for cornicle wax luring predators in some cases.[4]

References[edit]

  1. ^ Aphid, Henry G. Stroyan, McGraw-Hill Encyclopedia of Science and Technology, 8th Edition, 1997, ISBN 0-07-911504-7
  2. ^ Defence by Smear: Supercooling in the Cornicle Wax of Aphids, John S. Edwards, Letters to Nature, Nature, 211, 73–74, 2 July 1966; doi:10.1038/211073a0
  3. ^ Aphid, Candace Martinson, World Book Encyclopedia, 2008, ISBN 978-0-7166-0108-1
  4. ^ Kairomonal effect of an aphid cornicle secretion onLysiphlebus testaceipes (Cresson) (Hymenoptera: Aphidiidae), Tessa R. Grasswitz and Timothy D. Paine, Journal of Insect Behavior, Springer Netherlands, ISSN 0892-7553 (Print) 1572-8889 (Online), Issue Volume 5, Number 4 / July, 1992, doi:10.1007/BF01058190