Pheromonal specificity

After considering the evolutionary origins of the olfactory system and some basic principles of olfaction, this brief review examines one of the most extensively studied examples of neural processing of semiochemical information the sex pheromone-specific olfactory subsystem in male moths. This male-specific subsystem can be viewed as representing an exaggeration of organizational principles and functional mechanisms that are characteristic of olfactory systems in general. 

Olfactory Transduction in Pheromone-Specific Receptor Cells... 

The male moth s pheromone-analyzing olfactory subsystem is composed of pheromone-specific antennal ORCs projecting to the similarly specialized, anatomically defined MGC in the AL and MGC output neurons that project to olfactory foci in the protocerebrum. This subsystem is an example of a labeled-line pathway (18). Its specialization to detect, amplify, and analyze features of sex-pheromonal signals and its consequent exaggeration of common olfactory organizational principles... 

In contrast to the evidence for primers, signalers, and modulators, there is no decent evidence to suggest that there are human releaser pheromones. That is not to argue that there are none but to state that there is no evidence for them at present. Nonetheless, products purported to be human releaser pheromones—specifically sex attractants—are widely available on the Internet. They go by such suggestive names as Scent of Eros, The Edge, Alter-ego, and Pheromone Additive. Many of these products contain either androstenone or androstenol, steroids of unknown influence on the human emotional state. 

Hansson B. S., Hallberg E., Lofstedt C. and Steinbrecht R. A. (1994) Correlation between dendrite diameter and action potential amplitude in sex pheromone specific receptor neurons in male Ostrinia nubilalis (Lepidoptera pyralidae). Tissue Cell 26, 503-512. 

Ochieng S. A., Park K. C. and Baker T. C. (2002) Host plant volatiles synergize responses of sex pheromone-specific olfactory receptor neurons in male Helicoverpa zea. J. Comp. Physiol. A 188(4), 325-333. 

Pheromones of insect species in the order Coleoptera are characterized by considerable structural diversity. Unlike the lepidopterous sex pheromones, which are nearly all tatty acid derivatives, coleopterous sex pheromone structures range in complexity from the relatively simple 3,5-tetradecadienoic acid of the black carpet beetle to the tricyclic terpenoid, lineatin, of the striped ambrosia beetle. While the sex pheromones of many beetles consist of mixtures of compounds that act synergistically to elicit a behavioral response, other Coleoptera species appear to use only a single compound for chemical communication between the sexes. In the latter case the compound usually has at least one chiral center and chirality plays a major role in determining pheromone specificity. 

H. Ljungberg, P. Anderson and B.S. Hansson, Physiology and morphology of pheromone-specific sensilla on the antermae of male and female Spodoptera littoralis (Lepidoptera Noctuidae), J. Insect Physiol. 39 (1993) 253-260. 

B.S. Hansson, Antennal lobe projection patterns of pheromone-specific olfactory receptor neurons in moths, in Insect pheromone research new directions, R.T. Carde, A.K. Minks (eds.), Chapman Hall New York, (1997), pp. 164-183. 

In aquatic systems, solubility takes the place of volatility. Aquatic pheromones can be large molecules so long as they are soluble in water (though contact pheromones, such as those used in mate recognition in shrimp and copepods are presumably almost insoluble - see e.g., Bauer, Chap. 14 and Snell, Chap. 23). Many aquatic organisms use polypeptides as pheromones, for example the crab pumping pheromone (Rittschof and Cohen 2004). Pheromone specificity can be gained by... 

Evidence for Pheromonal Specificity. Existing empirical information on the specificity of fish hormonal pheromones is fragmented and inconclusive. Notably, no spe-... 

Carde, R. T., Carde, A. M., Hill, A. S. and Roelofs, W. L. (1977) Sex pheromone specificity as a reproductive isolating mechanism among the sibling species Archips argyro-spilus and A. mortuanus and other sympatric tortricine moths (Lepidoptera Tortri-cidae). J. Chem. Ecol., 3, 71-84. 

Jewett, D. M., Matsumura, F. and Coppel, H. C. (1976) Sex pheromone specificity in the pine sawflies interchange of acid moieties in an ester. Science, 192, 51-3. 

Roelofs, W. L. and Comeau, A. (1969) Sex pheromone specificity Taxanomic and evolutionary aspects in Lepidoptera. Science, 165, 398-400. 

Muller, D.G., Maier, L, and Gassmann. G. (1985b) Survey on sexual pheromone specificity in Laminariales (Phaeophyceae). Phycologia,... 

Many sympatric tortricine moths possess overlapping chemical communication systems because at least one component of their pheromones is either a 14-carbon chain acetate, alcohol or aldehyde, with unsaturation in the Cn-12 position. The species recognition of distinctive pheromone blends, together with non-pheromonal reproductive isolating mechanisms such as habitat preferences and differential mating times have been discussed by Card et al 500). This article, together with the literature cited therein, should be read to obtain an informed view of pheromone specificity and its significance in tortricine moths. 

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