Pheromones Subject

While the existence of a female produced sex pheromone in the Colorado potato beetle Leptinotarsa decemlineata has been the subject of controversy for many years (for a discussion see [368]) a male produced pheromone has... 

Only a few compounds or mixtures of compounds have been shown beyond doubt to be mammalian pheromones. This is the main reason why the subject matter of this chapter is not restricted to pheromones and why exocrine secretions and other mammalian excretions in general will be discussed as possible sources of pheromones, even though their role in the chemical communication of the species under discussion has not yet been established. Feeding deterrents are not discussed. In general defensive secretions are also not discussed, but the anal sac secretions of the mustelids are included, because it is possible that these secretions could also fulfill a semiochemical role, in addition to being used for defense. 

The general subject of sex pheromones of cockroaches was last reviewed by Schal and Smith (1990). Reviews dealing with particular species are cited in the appropriate section. 

Analytical studies of the tergal secretions of male B. germanica have identified a number of volatile compounds, none of which has so far been subjected to behavioral assays on females. Brossut et al. (1975) found p-hydroxybenzyl alcohol, o-hydroxybenzyl alcohol, di- and tri-methylnaphthalene, benzothiazole, two isomers of nonyl phenol, and myristic, palmitic, and oleic acids. The fatty acids constituted > 92% of the volatile fraction given their abundance in feces and frass, and their role as putative aggregation pheromones (Wileyto and Boush, 1983 Fuchs et al., 1985 Wendler and Vlatten, 1993 Scherkenbeck et al., 1999),... 

In addition to the extremely low application rates, arthropod pheromones are extremely volatile, are subject to rapid environmental degradation, and are metabolized by enzyme systems present in most living organisms [39, 43]. Most of the USE P -registered products in the U S A are arthropod pheromones and, of those, the majority are straight-chain lepidopteran (butterfly and moth) pheromones (SCLPs). 

Three isomers of the substituted cyclobutanes 33, 34 and 35 are obtained by the [2+2] cycloaddition of isoprene, and separated at low temperature from other cooligomers without undergoing Cope rearrangement. When the mixture was subjected to hydroboration and oxidation, the alcohol 37 was obtained from the isomer 34, and easily separated from 35 and the diol 36. The alcohol 37 is a pheromone called grandisol [11]. Although overall yield was 15%, this is the shortest synthetic route to this pheromone. 

In the study by Sachse et al. (1999) it was shown that 2-heptanone evoked a specific activity pattern that differed from the corresponding alcohol or aldehyde more than functional groups differed at other chain lengths. 2-heptanone functions as a repellent scent marker in honeybees (Giurfa and Nunez, 1992 Giurfa, 1993). The pheromonal function of this substance may have paved the way for the development of an alternative specialized pathway. It cannot be excluded that non-sexual pheromones are subject to parallel processing, i.e. a second specialized pathway similar to the sexual pheromone pathways may be present in areas of the ALs not accessible for recording. 

The goal of this chapter is to provide an overview of the occurrence of Type II polyene pheromones and their derivatives, and their chemistry, including their biosynthesis and synthesis. The older literature in this subject area was reviewed in Millar (2000), and summarized more recently in Ando et al. (2004). Thus, this chapter will provide a comprehensive summary of all known Type II pheromone structures and their occurrence in Tables 1 1, whereas the text will focus more on work over the past ten years. The interested reader is further directed to three useful online databases, two of which focus on lepidopteran pheromones (www.tuat.ac.jp/ antetsu/review/e-List.pdf Ando, 2003 www-pherolist.slu. se/pherolist.php Witzgall et al., 2004) and the third of which covers insect pheromones in general (www.pherobase.com El-Sayed, 2008). 

Although pheromones are probably ubiquitous among species in the Insecta, serious chemical investigations of these compounds have been limited to species in about only one-fourth of the orders. Pest species, particularly those in the orders Lepidoptera and Coleoptera, have been subjected to considerable pheromonal scrutiny, and our knowledge of the chemistry of sex pheromones is primarily derived from compounds isolated from moths and beetles. On the other hand, the ants and bees (Hymenoptera) have proven to be an especially rich source of chemical releasers of social behavior, and chemisociality is now being explored more and more frequently in terms of identified signal molecules. 

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