Attractants and repellents

The insect s choice of food may be governed to a considerable extent, as ours is, by attractants and repellents. In many instances, the actual insecticidal action of plant extractives may be due primarily to an artificially high level of application, while, in fact, the parent plants are only repellent in the field. This repellency may appear to be resistance on the part of the plant, and the chemistry of such resistance factors has begun to receive much-needed attention. For example, Smissman and his coworkers have examined the chemical basis for the inherited resistance of some strains of corn to attack by the European corn borer. 6-Methoxybenzoxazolinone (X) was isolated (2, SO) and shown to be one of the principal resistance factors, and a number of synthetic analogs were found to... 

Dethier, V. G., Chemical Insect Attractants and Repellents, Blakiston, Philadelphia, 1947. 

Natural Insect Attractants and Repellents, New Tools in Pest Control... 

The simplest state of matter is a gas. We can understand many of the bulk properties of a gas—its pressure, for instance—in terms of the kinetic model introduced in Chapter 4, in which the molecules do not interact with one another except during collisions. We have also seen that this model can be improved and used to explain the properties of real gases, by taking into account the fact that molecules do in fact attract and repel one another. But what is the origin of these attractive and... 

Bate-Smith, E. C. (1972). Attractants and repellents in higher animals. Proceedings of the Phytochemistry Society 8,45-56. 

Dowd, P. F. In Natural Pesticides Volume V Insect Attractants and Repellents Morgan, E. D. Mandava, L. B. Eds. CBC Press Boca Raton, in press. 

Charles Du Fay (1698-1739) observed that charged objects both attracted and repelled objects and explained this by positing that electricity consisted of two different kinds of fluids. Du Fay called the two fluids vitreous and resinous electricity and said each of these two different fluids attracted each other, but each repelled itself. Benjamin Franklin (1706-1790) also con-... 

Dethier, V.G. "Chemical Insect Attractants and Repellents" Blakiston Philadelphia, 1947. 

Volatile compounds are often involved in long distance attraction and are especially important as attractants and repellents (as defined by Kogan, ). One major class of volatile materials, essential oils, is comprised of complex mixtures of terpenes, phenylpropanoid derived compounds and a number of esters, alcohols, aldehydes, ketones, acids, and hydrocarbons. The constituent compounds are mostly of low to medium molecular weight and generally not highly oxygenated. Some of the biological properties of these compounds have been reviewed (17,41,46,55,56). 

In addition to mating-disruption pheromones, there are a number of naturally occurring, nonpheromonal attractants and repellents. Many are typically used as food additives or in cosmetics or perfumes, and are derived from diverse plant and animal sources. Capsaicin [44], the spicy component of chili peppers, is used in several bird, deer, and rodent repellents. Maple lactone [45], a common food additive and flavoring, is used in traps to attract cockroaches with its stale beer odor. Methyl... 

Gun-cotton is considerably heavier than unprepared cotton, and may be distinguished therefrom by its harshness, and by tbe crepitating sound produced when pressed by the hand. When well made, there is scarcely any change in color or general appearance. It may also be known from common cotton by its electric condition for if a portion be pulled briskly between the finger and thumb of a dry hand, the fibres will adhere with great tenacity. If a strip of prepared paper ho thus treated, it will, on presenting one end to tho knuckle, be alternately attracted and repelled, and thus pait with its electricity. Gun-eottou Is also perfectly soluble in ether, and if the solution be poured on the surface of oold water, the xyloidin yields an opaque film thereon, which, when collected and dried, forms a remarkably explosive paper,... 

By classical, we mean models that do not take into account the quantum behavior of small particles, notably the electron. These models generally assume that electrons and ions behave as point charges which attract and repel according to the laws of electro-... 

Pith balls Pith is the spongy material found in the center of the stem of most plants. Pith balls are bits of pith attached to a string for use in scientific demonstrations to show how like electrical charges can attract and repel the balls. These days, pith is usually replaced by lightweight plastics in these demonstrations. 

Each of these observations or sightings has chemical ecology implications that will be discussed. The instructor will lead students to pertinent literature. Topics include, but are not limited to, feeding attractants and repellents palat-ability detoxication of plant secondary compounds marking with secretions or excretions chemical defense. 

Mechanical control methods for vertebrate pests include traps, barriers, gunning, attractants, and repellents. 

This list does not include those pesticides which are either not normally used as pest control agents (plant growth regnlators, defoliants, and desiccants) or are not directly toxic to the pest (attractants and repellents). 

Independently of their nature, attractant and repellent stimuli are integrated by the cell if applied simultaneously [25,40]. For example, a blue step-up (repellent) stimulus can be repressed in its repellent action by a green step-up (attractant) stimulus, provided an appropriate intensity ratio of both light colours is applied. Integration was also demonstrated for a symmetrically inverted stimulus program, i.e. a blue step-down... 

Two antagonistic stimuli, i.e. attractant and repellent, delivered at the same time cancel demethylation, therefore a feedback loop from the integrated signal to the demethylation system has to be postulated [46]. 

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