Pheromones aggregating

Some plant volatiles act synergistically with aggregation pheromones. Aggregation of the American palm weevil, Rhynchophorus palmarum, on host plants is mediated by host-plant volatiles and a male pheromone (rhynchophorol).60 Acetoin, one of the major volatile components of the host plants Cocos nucifera, Saccharum officinarum, Jacaratia spp., and Elaeis spp., plays an important role in the aggregation of weevils on these plants. Although the pheromone alone is weakly attractive, its attraction is enhanced by acetoin. 

Pheromones are classified into two categories, releaser pheromones and primer pheromones. Releaser (or signaller) pheromones cause changes of behaviors in the receivers, while primer pheromones cause physiological impacts on the receivers. Releaser pheromones can be further classified as sex pheromones, aggregation pheromones, trail pheromones, etc., according to the type of behavioral change. 

Pheromones are divided into primer and releaser pheromones. They are also classified according to what kind of reaction they induce in the receiver, e.g., sexual pheromones, aggregation pheromones, or alarm pheromones. Substances used in baits to attract animals are called lures. They may be pheromones, synthetic analogues of pheromones, or other attractants. 

Kay, R. H. (1976) Behavioral components of pheromonal aggregation in Aphis fabae Scopoli. Physiol. Ent., 1, 249-54. 

Much of the communication between insects involves chemical messengers called pheromones A species of cockroach secretes a substance from its mandibular glands that alerts other cockroaches to its presence and causes them to congregate One of the principal components of this aggregation pheromone is the alkane shown in the bond line formula that follows Give the molecular formula of this substance and represent it by a condensed formula... 

The western pine beetle Dendroctonus brevicomis is perhaps the most destmctive insect enemy of western pine forests. The aggregation pheromone is a mixture of the terpenoid myrcene [123-35-3J (163) from the tree and the frass pheromones exo-hsevicomki [20290-99-7] (164) and frontalin [28401-39-0] (165). The Norway spmce beede Ips tppopraphus converts the tree terpenoid myrcene into the frass pheromone ipsdienol [33628-00-3] (166) and the beedes also produce 2-methyl-3-buten-2-ol [115-18-4] and rir-verbenol [473-67-6] (167), all of which are components of the aggregation pheromone. 

Similar pheromone blends are produced by other species of bark beedes and these complex aggregation pheromones have been used extensively in mass trapping programs, capturing millions of bark beeties and preventing them from further attacking valuable forest resources. 

The aggregation pheromone of the boU weevil, Jinthonomusgrandis is a mixture of the alcohols D-i7j -2-isopropenyl-l-methylcyclobutaneethanol [30820-22-5] (168) and OT-3,3-dimethyl-A, p-cyclohexaneethanol [26532-23-0] (169) and of the cis- and trans-isomers of the aldehyde of the latter (170). The pheromone is marketed as grandlure [11104-05-5] for monitoring and removal trapping of boU weevil populations. 

Fpobtem Suggest a synthesis of optically active S-(+)-sulcatol (13), the aggregation pheromone of the wood-boring ambrosia beetle, from available ethyl (S)-(-)-lactate (14). 

The reaction in Entry 5 was used in the syntheses of linetin, which is an aggregation pheromone of the ambrosia beetle. In Entry 6, a transannular 5-exo cyclization occurs. Entry 7 is an example of formation of a lactone by carboxylate capture. In this case, the product was isolated as the mercurochloride. 

This method has been applied to the synthesis of (S)-2-methyl-4-octanol, an aggregation pheromone of Metamasius hemipterus.56... 

Graves B.M., Halpem M. and Friesen J.L. (1991). Snake aggregation pheromones source and chemosensory mediation in Western Ribbon snakes (Thamnophis proximus). J Comp Psychol 105, 140-144. 

Many different functions of pheromones have been found since Butenandt. Aggregation pheromones attract both sexes to a special location, while sex pheromones are offered by one sex only to attract or arouse the other one. Trail pheromones used by ants mark food trails and alarm pheromones change the state of alertness of conspecifics. These are only some of the functions pheromones can have, and similar different functions can be found in allelochemicals as well. 

Scheme 27 summarizes Yamamoto s synthesis of lardolure (16), the aggregation pheromone of the acarid mite, Lardoglyphus konoi [45]. The key-step was the transformation of acetal A to hemiacetal B. 

Four different syntheses were reported for the enantiomers of l-methyl-2-cyclohexen-1 -ol, a component of the aggregation pheromone of Dendrocton us pseudotsugae [47-50]. 

Sitophilate [1-ethylpropyl (2S,3 )-2-methyl-3-hydroxypentanoate, 24] is the male-produced aggregation pheromone of the granary weevil (Sitophilus granarius). Its racemate is also bioactive. Almeida synthesized ( )-24 by diaster eoselective hydrogenation of the Baylis-Hillman adduct A to B as shown in Scheme 37 [60]. This high diastereoselectivity could be observed only with TBS-protected ester A to give pure B. 

The aggregation pheromone of the broad-horned flour beetle (Gnatocerus cornutus) was reported to be (lJR,4i, 5S)-(+)-acoradiene (33) by Tebayashi et al. [72]. Scheme 47 shows Mori s synthesis of (lRy4Ry5S)-33 [73]. The key-step was the ring-closing olefin metathesis of A to give B. An X-ray analysis of C confirmed the structure shown. The product (lJR,4JR,5S)-33, however, was different... 

S)-3,7-Dimethyl-2-oxo-6-octene-l,3-diol (39) was recently identified as the aggregation pheromone of the Colorado potato beetle (Leptinotarsa decem-lineata), and synthesized by Oliver et al., starting from (S)-linalool [86]. An improved synthesis of (S)-39 by Mori is shown in Scheme 57 [87]. Enzymatic acetylation of ( )-2,3-epoxynerol (A) with vinyl acetate and lipase PS gave B together with C. The acetate B was converted to a multi-gram quantity of (S)-39 according to Oliver [86]. 

Abstract Pheromones are utilized by many insects in a complex chemical communication system. This review will look at the biosynthesis of sex and aggregation pheromones in the model insects, moths, flies, cockroaches, and beetles. The biosynthetic pathways involve altered pathways of normal metabolism of fatty acids and isoprenoids. Endocrine regulation of the biosynthetic pathways will also be reviewed for the model insects. A neuropeptide named pheromone biosynthesis activating neuropeptide regulates sex pheromone biosynthesis in moths. Juvenile hormone regulates pheromone production in the beetles and cockroaches, while 20-hydroxyecdysone regulates pheromone production in the flies. 

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