Pheromones play a pivotal role in human attraction. Detected by the vomeronal organ, pheromones can increase feelings of sexual desire, attraction, and comfort between the opposite sex.
Top Pheromones In Insects
The science of pheromones equally applies to insects. Such activity (Verron and Barbier 1962) and the substance has been detected in Kalotermes ﬂavicollis, although it has not been positively identiﬁed as the scent- trail pheromone of the species. On the other hand, the complex, unsaturated alcohol, n-cis-3, cis-6, trans-8-dodecatrien-1-ol (ﬁg. l3.4f), that occurs in large quantities in wood infected with the fungus Lenzites trabea Pers. (Matsumura et al. 1968, 1969) deﬁnitely appears to be the substance used for trail-laying by the several species of Reticulitermes that feed on this material.
The scent-trail pheromone of several Australian species of the widespread genus Nasutitermes was first isolated from N. exitiosus (Moore 1966). Later named nasutene (or more systematically, neocembrene-A), this compound had the constitution of a diterpene hydrocarbon, CZOH32 , but the complete determination of its structure proved a difficult chemical problem that has only recently been resolved (Birch et al. 1972). The pheromone has a curious 14-membered ring structure (fig. l3.4g) and is surprisingly stable for a compound of its class. The same substance has been detected in several other species of Nasutitermes, towards which it also shows trail-laying activity, and in Coptotermes lacteus (Froggatt), which registers no such response.
Although it has not yet been positively identified as a constituent of the food-timber, extracts from the fresh termite-susceptible timber of Eucalyptus certainly show trail-laying activity towards Nasutitermes species. Moreover, an apparently identical compound has been isolated in relatively large quantities from the Indian incense cedar, Commiphora mukul (Hooker ex Stocks) (family Burseraceae) by Sukh Dev and his associates (Patil et al. 1973). The latter isolate, named cembrene-A by its discoverers, is indistinguishable, physiochemically, from nasutene and it shows identical behavior in the trail-laying test.
On the other hand, the attractant for Nasutitermes exitiosus first detected in oil from the western Australian sandalwood (Santalum (= Eucarya) spicatum R. Br.) (Moore 1966) and recently identified as a sesquiterpene hydrocarbon, C15 H26 (fig. 13.4h), related to famesene (Birch et al. 1970), has only about one-thousandth of this activity. It appears to be no more than a moderately effective molecular mimic. Check out 2017 Top Pheromones | Pheromones-Planet.com.
Species-specificity in pheromone scent-trails based upon the same basic pheromone is apparently achieved through the presence of secondary components of greater volatility. Thus, in laboratory tests of interspeciﬁc activity, trails laid from extracts of one species of Nasutitermes were initially repellent to another, but they became increasingly more acceptable after periods of airing (Moore unpublished). By con- trast, trails prepared from purified nasutene showed no such period of induction. Now that the pheromone has been identified and is readily available from the Indian plant source, it would be of interest to determine whether it forms the basis of trail-laying in any of the numerous exotic species of Nasutitermitinae. Mean- while, it is at least clear that this substance plays a key role in the biology of both terrestrial and arboreal species, in the Australian fauna.