Cornicle

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Aphid excreting defensive fluid from the cornicles Aphid-sap2.jpg
Aphid excreting defensive fluid from the cornicles
Cornicles Cornicle. Aphid.jpg
Cornicles

The cornicle (or siphuncule) is one of a pair of small upright backward-pointing tubes found on the dorsal side of the 5th or 6th abdominal segments 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 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]

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Aphid Superfamily of insects

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<i>Rhopalosiphum maidis</i> Species of true bug

Rhopalosiphum maidis, common names corn leaf aphid and corn aphid, is an insect, and a pest of maize and other crops. It has a nearly worldwide distribution and is typically found in agricultural fields, grasslands, and forest-grassland zones. Among aphids that feed on maize, it is the most commonly encountered and most economically damaging, particularly in tropical and warmer temperate areas. In addition to maize, R. maidis damages rice, sorghum, and other cultivated and wild monocots.

Lachninae Subfamily of insects

Lachninae is a subfamily of the family Aphididae, containing some of the largest aphids, and they are sometimes referred to as "giant aphids". Members of this subfamily typically have greatly reduced cornicles compared to other aphids, and the group has sometimes been classified as a separate family.

<i>Aphis craccivora</i> Species of true bug

Aphis craccivora, variously known as the cowpea aphid, groundnut aphid or black legume aphid, is a true bug in the family Aphididae. Originally of probable Palearctic origin, it is now an invasive species of cosmopolitan distribution.

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<i>Aphis pomi</i> Species of true bug

Aphis pomi, commonly known as the apple aphid, or the green apple aphid, is a true bug in the family Aphididae. It is found on young growth of apple trees and on other members of the rose family where it feeds by sucking sap. Reproduction is mainly by parthenogenesis, in which unmated females give birth to live young.

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References

  1. Aphid, Henry G. Stroyan, McGraw-Hill Encyclopedia of Science and Technology, 8th Edition, 1997, ISBN   0-07-911504-7
  2. Edwards, John S. (1966). "Defence by Smear: Supercooling in the Cornicle Wax of Aphids". Nature. 211 (5044): 73–74. Bibcode:1966Natur.211...73E. doi:10.1038/211073a0.
  3. Aphid, Candace Martinson, World Book Encyclopedia, 2008, ISBN   978-0-7166-0108-1
  4. Grasswitz, Tessa R.; Paine, Timothy D. (1992). "Kairomonal effect of an aphid cornicle secretion on Lysiphlebus testaceipes (Cresson) (Hymenoptera: Aphidiidae)". Journal of Insect Behavior. 5 (4): 447–457. doi:10.1007/BF01058190.