Chemical contact

Agency Contact (Chemical Manager) Jewell D. Wilson, Ph.D. 

Dearman, R J. and Kimber, I., Differential stimulation of immune function by respiratory and contact chemical allergens. Immunology, 72, 563, 1991. 

Agency Contact (Chemical Managerl Selene Chou... 

The ovlposltlon behavior of Paplllo butterflies has been studied In some detail. Gravid females of the citrus butterfly, Paplllo demoleus, are attracted to host and non-host plants almost equally by color. But the specific attractant emitted from citrus plants Increases the chances of landing on these plants. Then contact chemical stimuli elicit the ovlposltlonal response of the butterflies (44). 

For further information, contact Chemical Products Department, 18000 Pacific Highway South, Suite 900, Seattle, WA 98188. 

One of the earliest records of pheromones in spiders was made by Lendl (1887— 88), who described an odor emanating from female Geolycosa vultuosa (as Trochosa infemalis) (Lycosidae), which attracted males. Subsequent work by Bristowe and Locket (1926) described male lycosid courtship displays (in the absence of the females) in response to contact chemical stimuli. Kaston (1936) demonstrated that female appendages released courtship in males, and that the activity was lost after extraction with ether. These observations were confirmed for several other species by various authors (reviews Leborgne, 1981 Tietjen and Rovner, 1982 Pollard etal., 1987 Stewart, 1988). 

Sugarcane Sower initiation is dependent on day length, temperature, age, moisture, and variety, and can be prevented by chemical applications at, or very close to, the date of floral initiation. The effective chemicals have been of two types (a) photosynthetic inhibitors, such as 3-(p-chlorophenyl)-1,1-dimethylurea (monuron), or (b) leaf-burning, contact chemicals. The very effective bipyridylium herbicides 6,7-dihydrodipyrido[l,2-a 2, r-c]pyrazidinium dibromide (diquat) and 1, l -dimethyl-4,4 -bipyridinium bis (methyl sulfate) (paraquat) combine the two properties, although the... 

Chemists are subject to the same hazards as artists from long-term, direct contact with toxic chemicals. In addition, some highly toxic chemicals can be deadly on single contact. Chemical warfare makes use of this knowledge. Fortunately, most chemists and artists will never come in contact with such chemicals. 

Agency Contact ( Chemical Manager) Patricia Richter... 

The external cuticle of insects is covered by a waxy layer composed of mixtures of hydro-phobic lipids that include long-chain alkanes, alkenes, wax esters, fatty acids, alcohols, aldehydes, and sterols. The primary purpose of this layer is to maintain water balance and prevent desiccation, as described in Chapter 6, but many of the cuticular lipid components have important secondary roles as intraspecific contact chemical signals (pheromones). These roles include species and sex recognition during reproductive interactions, and nestmate recognition and other colony organization functions in social insects. Thus, these compounds are essential mediators of insect behaviors. Cuticular compounds are also exploited by parasitoids and predators as interspecific contact cues (kairomones) to aid in host location. 

Most of the present book is dedicated to one class of Arthropoda, the Insecta, because chemical communication research in this class is the most complete and broadly illustrated. This type of research on the chelicerate arthropods of the class Arachnida is, by contrast, poorly developed. We saw for example in Chapter 7, studies of chemical ecology interactions with Acari and particularly mite-insect interactions, and a few examples of chemical interaction with spiders were also shown in the same chapter on chemical mimicry, even though spiders are the most familiar and numerous of the arachnids. We undertook some work and about 15-10 years ago on contact chemical signal description and its relationship with behavior, physiology and reproduction, in different types of Aranea (spiders). We will present here a distillation of this work with a review of studies on the subject by different authors. Most notable here is the poverty of research on contact recognition signals and relative behavioral works on the order Scorpionida, the scorpions. Some of the few chemical data available are published here for the first time. 

This work needs to be completed by performing more behavioral tests and also electro-physiological assays to test synthetic and natural blends as well as isolated compounds. We know that non-congenerous HCs can be detected by ant antennae (see Chapter 10 for a review) so it should be possible, since the chemicals are available, to perform similar sensory physiology tests on pectines, which seem to have a function in the detection of contact chemicals (G. and B 2001) or other chemosensory sensitive parts of the scorpion body. In conclusion this chemical ecology work is only preliminary, but it appears to point in the same direction as behavioral studies by our American colleagues. 

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