Sap-sucking insects in forests

Type :

Presentation

Pages :

5 pages

Format :

.doc

Published date :

11/25/2008

Category :

Science & technology

Sub category :

Biology

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Summary :

Introduction.
Mode of feeding and nitrogen metabolism.
Regional distribution and abundance.
Ecology.
Direct effects of sapsucker infestation.
1. The presence of the wood ant.
2. Aphid-infested sycamore saplings.
3. The width of the annual rings of sycamore.
Indirect effects of sapsucker infestation.
1. The honeydew excreted by aphids feeding on the leaves and needles.
2. The effects of microorganisms on throughfall chemistry.
Conclusion.

Abstract

insects of the order Hemiptera have mouthparts specialized for piercing and sucking, and within the suborder Homoptera of this order two groups, the Auchenorhyncha and Sternorhyncha, speciﬁcally feed on plants. As their general name implies these insects feed on the sap of plants. This can be the sap of individual mesophyll or palisade cells of leaves or the translocating elements of plants, in particular phloem. In feeding on phloem sap not only has these insects access to a more continuous supply of food but they can inject disease-causing organisms and saliva containing physiologically active chemicals, which are then translocated throughout a plant. In addition by telescoping generations aphids have overcome the developmental constraint and for their size achieved prodigious rates of increase. As a consequence aphids often become very abundant and so in addition to any indirect damage they can be extremely damaging because of the nutrient drain they impose on plants. That is, many phloem feeders in particular are such serious pests of trees that they threaten their survival, e.g., the scale insects Carulaspis minima and Lepidosaphes newsteadi attacking Bermuda cedar on Bermuda and Orthezia insignis attacking the native gumwood on St Helena.