Pheromones hydrocarbon

A number of hydrocarbon pheromones are known, chiefly in the Diptera, but also among Lepidoptera (see later). Sometimes hydrocarbons are part of the defensive secretion, as in the confused flour beetle, Tribolium confu-sum, which uses terminal alkenes e.g., 1-pentadecene, 1-hexadecene and 1-heptadecene, formed as described above. They are frequently found accompanying terpenes or oxygenated compounds in the secretions of many social insects, and Q to C,5 alkanes frequently accompany formic add in defensive secretions, where they are thought to act as spreading agents. 

The major sex pheromone of the female housefly Musca domestica is (Z)-9-tricosene. Incubating a mixture of (Z)-15-[1- C]- and (Z)-15- 

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The site of pheromone production in flies and cockroaches that utilize hydrocarbons is similar to that of the moths. Oenocyte cells produce the hydrocarbon pheromone which is transported by lipophorin in the hemolymph to epidermal cells throughout the body for release from the cuticular surface in general [20,21]. 

Marine lipophilic semiochemicals are well known, in particular the C hydrocarbon pheromones of brown algae (Oldham 19%, Chart 8.2.FA/PO). Hydrophilic semiochemicals, which are more difficult to identify, are also emerging. Those from tobacco plants are the first known multiple polypeptide hormones deriving in plants from a polyprotein precursor, like in animals and yeast (Pearce 2001). 

The site of hydrocarbon pheromone production in the nitidulid beetles has been identified as very large, round abdominal cells, connected to the tracheal system by fine ducts (Dowd and Bartelt, 1993 Nardi et al., 1996). The secretory cells contain several lipid spheres (presumably pheromone and pheromone precursors), and are dramatically larger in beetles that are actively emitting pheromone (Nardi et al., 1996). Pheromone apparently diffuses from the cells,... 

The role of hemolymph in transporting hydrocarbons and hydrocarbon pheromones has only recently become fully appreciated. Older models of hydrocarbon formation showed epidermal-related cells (oenocytes) synthesizing and transporting hydrocarbons directly to the surface of the insect (Hadley, 1984). In the housefly, the role of hemolymph is most clearly seen when (Z)-9-tricosene production is initiated. (Z)-9-Tricosene first accumulates in the hemolymph, and then after a number of hours, is observed on the surface of the insect. Modeling of the process (Mpuru el al., 2001) showed that the delay is surprisingly long, more than 24 h are necessary for transportation from site of synthesis to deposition on the surface of the insect. 

Further evidence that oenocytes are the cell type involved in hydrocarbon production was obtained by Wicker-Thomas et al. (unpublished data). The enzyme involved in the final step in hydrocarbon production, a cytochrome P450 that oxidatively decarbonylates aldehydes, was RNAi silenced specifically in oenocytes of both male and female D. melanogaster, resulting in marked inhibition of hydrocarbon production. The RNAi-silenced insects produced less than 10% of the hydrocarbon compared to control insects. Thus, the available evidence overwhelmingly supports oenocytes, whether associated with epidermal tissue or present in the peripheral fat body, as the site of cuticular hydrocarbon production. In some cases, even the shorter-chain hydrocarbon pheromones and pheromone precursors (see below) are produced in oenocytes. 

Hefetz, A. (2007). The evolution of hydrocarbon pheromone parsimony in ants (Hymenoptera Formicidae) - interplay of colony odor uniformity and odor idiosyncrasy a review. Myrmecol. News, 10, 59-68. 

Second, the decarboxylase enzymes required to produce hydrocarbons apparently are not present in lepidopteran pheromone glands, but these enzymes are present in oenocyte cells where most insect hydrocarbon synthesis takes place (Blomquist et al., 1987). Thus, Lepidoptera that produce Type II pheromones must have a mechanism for transport of hydrocarbon pheromone components from the oenocytes to the pheromone gland, where... 

Volatile hydrocarbon pheromones from beetles Summary of male-specific hydrocarbons... 

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