Insects cockroach identification

The EAG technique as a bioassay tool for active fractions has been used in the identification of sex pheromones of many insect species in several orders and remains as a key factor in the identification of pheromones. In the recent identification of the brownbanded cockroach pheromone supellapyrone (7) (Figure 2), the EAG technique was used throughout the entire process of isolating and purifying active material from 12,000... 

Insects at the interfaces between agricultural and urban pests, e.g. termites, and between medical and urban pests, e.g. flies, wasps, and cockroaches, have been extensively studied. Since morphological identification of many close species is difficult, not only at various larval stages but also at the adult stage, detection of even small differences in cuticular compounds can be useful. A full presentation of all evidence to support this claim is beyond the scope of this chapter and would be repetitive. Instead, this section presents a few typical examples in which CHC analysis has been used to study insects with economic impact in various sectors. 

Methods for the collection, isolation, and identification of insect sex attractants have been discussed in the book by Jacobson (1965)l On the basis of NMR, infrared, paper chromatographic, and chemical data the attractant of the American cockroach, Periplaneta americana, has been identified (Jacobson et al., 1963) as 2,2-dimethyl-3-isopropylidenecyclopropyl propionate, but this structure has been found to be incorrect by synthesis of an inactive compound with the assigned formula (Day and Whiting, 1964 Jacobson and Beroza, 1965 Wakabayashi, 1965). The structural formula of the sex attractant had not been finally realized (in 1965), but the empirical formula was known to be CiiHj802. Infrared, NMR, and mass spectrometry have been used frequently in these investigations. 

The use of GC-EAD allows the rapid screening of compounds and extracts in order to identify those eliciting a response and eliminate those not detected by the insect. GC-EAD takes full advantage of the separation capabilities of GC together with the detection capabilities of the EAD. Stereochemical determination can also be achieved using GC-EAD, and the use of chiral stationary phases allowed the stereochemical identification of the sex pheromone of the brown-banded cockroach. 

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