Encyclopedia of Entomology

2008 Edition
| Editors: John L. Capinera


Reference work entry
DOI: https://doi.org/10.1007/978-1-4020-6359-6_4007

This generally is a liquid secretion of the salivary glands (= labial glands), but sometimes apparently originating from the crop, into the buccal cavity (mouth) of the insect. The saliva consists of water, salts, proteins, and enzymes, though sometimes it contains plant growth regulators or is contaminated with plant disease organisms such as viruses. Although digestion is an important aspect of saliva, it also serves to lubricate the mouthparts and aids in swallowing. In piercing-sucking insects that penetrate plants, saliva also may harden to form tubes or “sheaths” that hold the mouthparts (stylets) firmly in place and help prevent leakage while the insect sucks up liquids from the phloem or xylem. The saliva also hinders the plants’ response to injury and feeding, to the benefit of the insect. Piercing-sucking insects normally have a salivary canal for secretion of saliva plus a food canal for food uptake, but thrips (Thysanoptera) have only a single canal, the food canal, that...

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© Springer Science+Business Media B.V. 2008