Pheromones contact

While these functionalized ethers maybe long range signals,long chain unsaturated ketones, isolated from the elytra of females of the related species Anoplophora malasiaca, act as contact pheromones. The mixture of 10-hepta-cosanone, (Z)-18-heptacosen-10-one, (18Z,21Z) -18,21 -heptacosadien-10-one and (18Z,21Z,24Z)-18,21,24-heptacosatrien-10-one 188 proved to show pronounced biological activity [349]. 

Pardosa hortensis s Female contact pheromone releases courtship behavior in males Robert and Krafft, 1981... 

Courtship behavior of Dysdera crocata, a specialized feeder on woodlice (Pso-coptera), is released by contact with nest silk or the cuticle of a live or even dead female. Washing with ether rendered these substrates inactive, suggesting the presence of a lipophilic contact pheromone (Pollard et al., 1987). 

Volatile sex pheromones provide the first specific information about mating partners. Cuticular contact pheromones provide a second step in species and sex recognition and, in most cases, they function as courtship-inducing pheromones... 

Fig. 6.1b). Although they are probably present in most cockroach species, sex-specific contact pheromones have been identified in only a few species. They are thought to be distributed throughout the epicuticular surface and are perceived by means of antennal contact and with the mouthparts. Female-produced contact pheromones elicit courtship responses in males however, in some cockroaches, stridulation and hissing may combine with, or operate in place of, contact chemore-ception. In addition, male contact pheromones may function to inhibit courtship in other males. 

A non-volatile contact pheromone contained in the cuticular wax of females elicits a wing-raising courtship response from males (Roth and Wilhs, 1952 Ishii, 1972). Nishida and co-workers obtained three active chromatographic fractions from hexane extracts of 224000 females. The major active component was identified as... 

Table 6.3. Chemical structures of the principal identified contact sex pheromones of cockroaches, listed by the species and sex that produces it contact pheromones are localized on the cuticular surface... 

The third, and perhaps least understood, mechanism regulating contact pheromone production involves its transport to the cuticular surface. The detection of large amounts of hydrocarbons and pheromone internally, within the hemolymph, prompted an examination of lipid transport in B. germanica. Gu et al. (1995) and Sevala etal. (1997) isolated and purified a high density lipoprotein, lipophorin, that carries hydrocarbons, contact pheromone, and JH within the hemolymph. The accumulated evidence supports the idea that the hydrocarbons and contact pheromone components are produced by oenocytes within the abdominal integument, carried by lipophorin, and differentially deposited in the cuticle and ovaries (Fan et al.,... 

A number of chemo- and mechanoreceptors participate in the male behaviors. The female contact pheromone is detected by chemosensilla on the antennae and labial and maxillary palps (Ramaswamy and Gupta, 1981). The number of these sensilla increases dramatically during the metamorphic molt, and much more so in males than in females. Unfortunately, no electrophysiological recordings have been conducted, and the specific sensillum type that responds to the contact pheromone... 

In comparison with volatile pheromones, little is known about chemoreception of contact pheromones. There is some indication that the physical structure, or texture, of the antenna plays a role in the response to contact pheromones, but the processing of these signals has yet to be investigated. Further, ablation experiments suggest that the palpi may be involved in pheromone reception, but electrophysiological and behavioral experimental support to demonstrate this unambiguously is lacking. 

The Siphonaptera is another group where a volatile sex pheromone is yet to be demonstrated, although a contact sex pheromone has been demonstrated in preliminary experiments (Ralph Charlton, personal communication). The source and nature of this contact pheromone is yet to be deciphered. Fleas have been speculated to use a certain wavelength of light, C02, and visual and thermal stimuli for host localization, as traps that present these kinds of stimuli seem to be effective in trapping fleas (Benton and Lee, 1965 Osbrink and Rust, 1985 Dryden and Broce, 1993). 

A number of studies since 1980 have concentrated on the search for a sex pheromone analogous to Muscalure, the first contact pheromone discovered in mature Musca domestica females (Carlson et al., 1971). Other hydrocarbons have been described in various Diptera (Carlson et al., 1978 Blomquist and Jackson, 1979 El Messoussi et al., 1994 Blomquist, Chapter 8, in this volume). In all cases, a cuticular hydrocarbon with low or no volatility and high abundance was necessary, but not sufficient for a response. Its action could be checked only... 

In insects, especially Diptera, several pioneer studies reviewed by Blomquist et al. (1987) established that long chain hydrocarbons, some of which play a pheromone role, were derived from very long chain fatty acids by reduction and decarboxylation. Thus, pheromone biosynthesis shares steps with those leading to basic lipid molecules and also with those of the well-known pheromones of Lepidoptera (Roelofs and Wolf, 1988). All often display several double bonds located in various positions while the volatile butterfly compounds bear functional groups (acetate, aldehyde or alcohol) and aliphatic chains with 12-16 carbons. Contact pheromones of flies have much longer chains (21C-39C) (Pennanec h et al., 1991). 

Central to investigations of the biosynthetic pathway and regulation of the contact pheromone of B. germanica was the observation that the major cuticular hydrocarbon in all life stages of this species is an isomeric mixture of 3,7-, 3,9-and 3,11-dimethylnonacosane (Jurenka el al., 1989). The presence of only the 3,11-isomer in the cuticular dimethyl ketone fraction and only in adult females prompted Jurenka et al. (1989) to suggest that production of the pheromone might result from the female-specific oxidation of its hydrocarbon analog. This scheme follows the well-established conversion of hydrocarbons to methyl ketone and epoxide pheromones in the housefly (Blomquist et al., 1984 Ahmad et al., 1987). 

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