Pheromones mimics

It is interesting to note that these compounds attract mainly the males of the respective species. Therefore, these compounds might be pheromone mimics. Protein hydrolysates, on the other hand, attract both sexes of most Tephritids and are widely used as food baits. However, volatiles from protein hydrolysates may not be simply food attractants. The cyclic imine, 3,4-dihydro-2H-pyrrole, has been identified in protein hydrolysate volatiles (12), and this compound has been identified by Baker and coworkers (11) as the sex pheromone Which attracts virgin females to the sexually mature male Medflies. Why the protein hydrolysate volatiles attract the males and other species remains unanswered. 

Manabe, S., Nishino, C. and Matsushita, K. (1985). Studies on relationship between activity and electron density on carbonyl oxygen in sex pheromone mimics of the American cockroach, part XI. Journal of Chemical Ecology 11 1275-1287. 

Nishino, C. and Kimura, R. (1981). Isolation of sex pheromone mimic of the American cockroach by monitoring with male/female ratio in electroantennogram. Journal of Insect Physiology 27 305-311. 

Nishino, C. and Manabe, S. (1983). Olfactory receptor systems for sex pheromone mimics in the American cockroach, Periplaneta americana L. Experientia 39 ... 

Pheromone mimic for M. josephi with no kairomonal activity for . hebraicus... 

Control of mating. A new type of sex pheromone was found present in Callosobruchus chlnensls, which is not a conventional sex attractant, but rather induces the male to extrude his genital organ and to effect copulation. A female dummy bearing the pheromone mimic, elicits copulation and ejaculation by the male. 

The frequent occurrence of pheromonal mimics in plants is disturbing in view of the oft-presumed specificity of pheromonal chemicals. One might wonder whether their presence in plants has communicative significance for cockroaches. A defensive strategy based upon the possession of a sex pheromone mimic seems of dubious value to a plant unless the stimulation to sexual activity overrides or depresses feeding activities. Alternatively, attraction of omnivorous cockroaches might result in their destruction of competing plants or parasites. 

It would also be very interesting to know whether there could be o whether there exists a pheromone mimic o whether a pheromone mimic could be developed which is devoid of the kairomonal activity in the presence of the pheromonal activity. This may be possible, considering the recent success in developing various pheromone mimics [14]. 

There are practical demands for the invention of pheromone mimics, because pheromones are often too labile to be used in pest control. Various mimics have been prepared to date, several of which will be described in this section. 

Verbanone and its derivatives are normally made by oxidation of a-pinene [usually (+ )-116] when Takayanagi and Nishino required (— )-trans-verbanone (822), they used a synthetic procedure starting from (+ )-apoverbenone [(+ )-823] accessible from the ( —)-p-pinene series. The Wharton reaction (hydrazine hydrate) with the (trons)-epoxide of 823 yields 824, which can be oxidized to (— )-apoverbenone [( —)-823], from which 822 was obtained by reaction with lithium dimethyl cuprate. [This work was actually to prepare verbanyl acetates, the (l/ ,2/ ,5/ )-series of which notably ( + )-825 is active as pheromone mimics in the cockroach Periplaneta americana, while the (15,2S,5S)-series from 822 are inactive. 

Nishino, C., Bowers, W. S., Montgomery, M. E. and Nault, L. R. (1976) Aphid alarm pheromone mimics Sesquiterpene hydrocarbons. Agric. Biol. Chem., 40, 2303-4. 

Flowers of some orchids mimic both the appearance and sex pheromone of virgin females of certain species of bees or wasps. This sexual deception results in pollination by male hymenoptera that would not normally visit flowers. Japanese honey bee drones (Apis cerana japonica) cluster on the oriental orchid (Cymbidiumpumilum) while on their mating flights [ 134]. By comparing volatile profiles of orchids and the female hymenoptera they mimic, or by GC-EAD and GC-MS analysis of orchid volatiles, several compounds have been identified that may mediate this attraction for the solitary bee Andrena nigroaenea [135, 136] and the scoliid wasp Campsoscolia ciliata [135]. 

Fig. 20.2 Pheromone delivery in Desmognathus ocoee salamanders and the method of pheromone delivery used during behavioural trials. A receptive female places her chin on the tail base of the male and typically straddles his tail. The male turns back towards the female and places his submandibular mental gland on her dorsum. The male then uses his premaxillary teeth to scratch the site on her dorsum that he has swabbed with his mental gland secretions. To mimic pheromone delivery in behavioural trials, each male was deglanded and a treatment solution was delivered to each female in a treatment patch (TrP) placed on her dorsum just posterior to the head. Photograph by Stevan J. Arnold...

The predators discussed up to this point search for prey by using their ability to perceive certain chemical clues. Some unusual predators have evolved the ability to attract their prey with scents that mimic the odor of a valuable resource (see reviews of chemical mimicry in refs. 9 and 39). Several groups of spiders lure male insect prey with scents that mimic the sex pheromone scents of females of the prey species (see reviews in refs. 9,13,40, and 41). To the best of our knowledge, these spiders are the only predators that mimic sex pheromones. However, the spiders share some similarities with the diverse orchids which mimic insect sex pheromones to lure pollinators (9, 42, 43) and with the predatory fireflies, which practice elaborate mimicry of visual sexual signals to lure their prey heterospecific male fireflies (44). 

Biologists have known of these intertwined lives for more than a century, but only more recently have they brought modern tools to bear on the relationship. Along with several other points, the role of chemical signals here is still unsettled. The moths may locate yucca flowers by scent, sight, or both. For such a scientifically well-known interaction, it would be interesting to know more. If yuccas do emit a chemical attractant, the scent apparently attracts only yucca moths, a selectivity suggesting an attractant that mimics some unsuspected moth pheromone. 

As discussed below, l,3,7-trimethyl-(Z)-2,6-octadienyl formate and 1,3,7-trimethyl-(Z)-2-octenyl formate, prepared as mimics of the aggregation pheromone structure, had alarm pheromone-like activity, whereas 1,3,7-trimethyloctyl formate and simplified 1-methylalkyl formates showed aggregation pheromone-like activity with C. lactis, whose alarm pheromone is neral (2) (Honma et al, 1995). The evidence suggests that for those species which use neral (2), geranial (6), or neryl formate (1) as alarm pheromones, the presence of (Z)- or ( )-allylic double bonds in the molecules are essential for biological activity. 

Haynes, . E, Yeargan, . V. and Gemeno, C. (2001). Detection of prey by a spider that aggressively mimics pheromone blends. Journal of Insect Behavior 14 535-544. 

Figure 6.16 Model illustrating interspecific regulatory differences in an early-stage reaction in isoprenoid pheromone biosynthesis between male Ips paraconfusus Lanier and Ips pini (Say). Feeding on host phloem results in synthesis of the full amount of the major pheromone component and full activity of HMG-R for both species. The impact of feeding on HMG-R transcript levels is yet to be determined. Topical treatment of male I. pini with JH III mimics feeding nearly completely in terms of pheromone mass and HMG-R activity. Topical treatment of male I. paraconfusus with JH III does not mimic feeding in terms of pheromone mass or HMG-R activity. Topical treatment of both species with JH III results in significantly enhanced levels of HMG-R transcript. One hypothetical explanation for the interspecific difference is that a second hormone (SH) or factor may be associated with the synthesis, stability, and/or activity of HMG-R in I. paraconfusus.

All life stages of the German cockroach produce 3,11-dimethylnonacosane, suggesting that production of a sex-specific contact pheromone may be less dependent on differentiation of sexually dimorphic pheromone glands, as is the case for volatile pheromones, and more so on the endocrine milieu of the adult female. Normally, adult male cockroaches produce much less JH III than do females, and males have a much lower titer of JH III in the hemolymph (Piulachs et al., 1992 reviewed in Tobe and Stay, 1985 Wyatt and Davey, 1996). However, when newly emerged males were exposed to filter papers treated with the JH mimic hydroprene they exhibited a six-fold elevation in female pheromone on their cuticle (Schal, 1988). Although substantial, this limited stimulation indicates... 

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