Skip Navigation


JXB Advance Access originally published online on January 31, 2006
Journal of Experimental Botany 2006 57(4):747-754; doi:10.1093/jxb/erj067
This Article
Right arrow Full Text Freely available
Right arrow FREE Full Text (PDF) Freely available
Right arrow All Versions of this Article:
57/4/747    most recent
erj067v1
Right arrow E-letters: Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when E-letters are posted
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrow Search for citing articles in:
ISI Web of Science (15)
Right arrowRequest Permissions
Right arrow Disclaimer
Google Scholar
Right arrow Articles by Douglas, A. E.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Douglas, A. E.
Agricola
Right arrow Articles by Douglas, A. E.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

© The Author [2006]. Published by Oxford University Press [on behalf of the Society for Experimental Biology]. All rights reserved. For Permissions, please e-mail: journals.permissions@oxfordjournals.org

FOCUS PAPER

Phloem-sap feeding by animals: problems and solutions

A. E. Douglas*

Department of Biology, University of York, PO Box 373, York YO10 5YW, UK

* E-mail: aed2{at}york.ac.uk

The incidence of phloem sap feeding by animals appears paradoxical. Although phloem sap is nutrient-rich compared with many other plant products and generally lacking in toxins and feeding deterrents, it is consumed as the dominant or sole diet by a very restricted range of animals, exclusively insects of the order Hemiptera. These insects display two sets of adaptations. First, linked to the high ratio of non-essential:essential amino acids in phloem sap, these insects contain symbiotic micro-organisms which provide them with essential amino acids. For example, bacteria of the genus Buchnera contribute up to 90% of the essential amino acids required by the pea aphid Acyrthosiphon pisum feeding on Vicia faba. Second, the insect tolerance of the very high sugar content and osmotic pressure of phloem sap is promoted by their possession in the gut of sucrase-transglucosidase activity, which transforms excess ingested sugar into long-chain oligosaccharides voided via honeydew. Various other animals consume phloem sap by proxy, through feeding on the honeydew of phloem-feeding hemipterans. Honeydew is physiologically less extreme than phloem sap, with a higher essential:non-essential amino acid ratio and lower osmotic pressure. Even so, ant species strongly dependent on honeydew as food may benefit from nutrients derived from their symbiotic bacteria Blochmannia.

Key words: Essential amino acids, Hemiptera, honeydew, phloem sap, sucrose


Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?


This article has been cited by other articles:


Home page
 GeneticsHome page
N. Qvit-Raz, E. Jurkevitch, and S. Belkin
Drop-Size Soda Lakes: Transient Microbial Habitats on a Salt-Secreting Desert Tree
Genetics, March 1, 2008; 178(3): 1615 - 1622.
[Abstract] [Full Text] [PDF]

Home page
 Appl. Environ. Microbiol.Home page
T. L. Wilkinson, R. Koga, and T. Fukatsu
Role of Host Nutrition in Symbiont Regulation: Impact of Dietary Nitrogen on Proliferation of Obligate and Facultative Bacterial Endosymbionts of the Pea Aphid Acyrthosiphon pisum
Appl. Envir. Microbiol., February 15, 2007; 73(4): 1362 - 1366.
[Abstract] [Full Text] [PDF]


Disclaimer:
Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.