Semiochemicals lipid

Poddar-Sarkar M. and Brahmachary, R.L. (1997) Putative semiochemicals in the African Cheetah Acinonyx jubatus). J.Lipid Mediator and Cell Signalling 15, 285-287. 

Tarsal, metatarsal, caudal, interdigital and preorbital glandular structures have been described in the black-tailed deer, Odocoileus hemionus columbianus. The tarsal organ received considerable attention from chemists and behavioral scientists during the early years of chemical research on mammalian semiochemicals. The major constituent of the complex mixture of volatile compounds associated with the tarsal hair tuft of this mule deer, (Z)-6-dodecen-4-olide [ 125], was subsequently found to be a mixture of the R and S enantiomers in a ratio of 89 11 respectively [ 126]. It was later found that this compound does not originate in the tarsal structure itself, but that it is extracted from the animal s urine by the tarsal hair tuft, which is specially adapted to extract lipids from urine [127]. 

The overall picture of the secretions of the dwarf antelope seems to suggest that secretions that are produced slowly are more complex. This could be explained in terms of microbiological action, which has more time to contribute to the complexity of a secretion, the slower it is produced. If this is indeed the reason for the complexity of secretions that are produced very slowly, it is possible that, in these animals, with exception of the klipspringer, the long-chain lipid constituents of the secretions could be controlled-release carrier materials rather than semiochemicals. If these heavy compounds were semiochemicals, it could be asked why is it necessary for an animal to spend so much energy to regularly renew its territorial marks. In retrospect, it is possible that up to now too much attention could have been devoted to the heavy constituents of the secretions, while the semiochemically active constituents could have been overlooked because they could be present in such low concentrations that they were not detected by the methods that were employed. 

It has become widely recognized over the past several decades that cuticular lipids, especially the hydrocarbons, function in chemical communication in many insect species (Howard, 1993 Nelson and Blomquist, 1995 Blomquist et al., 1998). Semiochemical functions attributed to hydrocarbons include sex attractants... 

As stated by Blomquist et al. (1998) in their chapter, the line of demarcation between glandular or cuticular release of semiochemical signals is not always clear . This statement echoes an earlier one by Blum (1985), who reported that insect exocrine glands consisting of modified epidermal cells located throughout the body could perform de novo biosynthesis and secretion of behavioral chemicals. Later, Blum (1987) put forth a unified chemoso-ciality concept proposing that epicuticular lipids carried numerous exocrine compounds and that the cuticle could be compared to a thin layer phase. Nevertheless, it is known that in various non-social insects epicuticular hydrocarbons are synthesized by modified cells often associated with the epidermis, the oenocytes (see above), and that these oenocytes can be located in several sites within insects. 

Dani, F. (2006). Cuticular lipids as semiochemicals in paper wasps and other social insects. Ann. Zool. Fennici, 43, 500-514. 

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