Enhancer Pheromones

Thus, although our analysis is preliminary, the differences that neonates detect and respond to behaviorally could very well be due to differences in relative quantities of constituents rather than their presence or absence. It is interesting that, even though B. constrictor and C, v. viridis are relatively distant taxonomically and live in vastly different habitats, there has been surprising conservativism in skin lipid structure during their evolution. It is possible that skin lipid chemical structure has remained relatively constant to maintain its apparent primary function, controlling CWL (Roberts and Lillywhite, 1980 Landmann, 1979, 1980), and that lesser changes have occurred to enhance pheromonal functions or effects in taxa where necessary selective pressures have existed. 

The production of a female-influencing secretion from the chin gland of male Plethodontid salamander (P. jordani) points to a similar extension of function by the acquisition of female olfactory sensitivity to an intercellular signal protein. Female receptivity is enhanced by a male cytokine-like compound of the interleukin-6 family, in its released form. Rollman et al. (1999) note that pheromonal activity is a previously unrecognised function for cytokines. 

AOS responsiveness to hormonal influences is shown in the action of sodefrin on the lateral nasal sinus of newts (Cynops). The receptors in the accessory pocket are differentially affected by pituitary and ovarian hormones (Toyoda et al., 2000). The local EOG response to the pheromone (Fig. 5.1) was enhanced by the presence of prolactin or of estrogen alone. Receptor sensitivity increase is perhaps an alternate strategy to AOS receptor density increase several alternate routes of signal receptor adaptation (Fig. 7.1) have been hypothesised (Sorenson and Stacey, 1998). 

McClintock M. (1983). Pheromomal regulation of the ovarian cycle enhancement, suppression and synchrony. In Pheromones and Reproduction in Mammals (Vandenberg J.G., ed.). Academic Press, New York, pp. 113-150. 

An example of a larval parasitoid that responds to the host sex pheromone is seen with Cotesiaplutellae (Braconidae), also a parasitoid of the diamondback moth. These insects were attracted equally to the pheromone blend (31,32,33, see above), the acetate 32, or aldehyde 31 components [80]. This larval parasitoid, however, was also strongly attracted to host frass volatiles, in particular, dipropyl disulfide 34, dimethyl disulfide 35, allyl isothiocyanate 36, and dimethyl trisulfide 37. In contrast, the egg parasitoid Trichogramma chilonis was only weakly attracted to 36. In both, T. chilonis and C. plutellae, plant volatiles, in particular (3Z)-hex-3-en-l-yl acetate 38, significantly enhanced attraction by the pheromone [80]. 

Plant volatiles [enhancement of pheromone attraction] (3Z)-Hex-3-en-l-yl acetate 38 [80]... 

Linepithema humile W-PvG Previously identified trail pheromone enhances consumption of sucrose solution (9Z)-Hexadec-9-enal 66 [179]... 

Rasmussen, L.E.L. and Riddle, S.W. (2004b) Development and initial testing of pheromone-enhanced mechanical devices for deterring crop raiding elephants A positive conservation step. J. Eleph. Manag. Assoc. 15, 30-37. 

Abstract A relatively small number of mammalian pheromones has been identified, in contrast to a plethora of known insect pheromones, but two remarkable Asian elephant/insect pheromonal linkages have been elucidated, namely, (Z)-7-dodecen-1-yl acetate and frontalin. In addition, behavioral bioassays have demonstrated the presence of a chemical signal in the urine of female African elephants around the time of ovulation. Our search for possible ovulatory pheromones in the headspace over female African elephant urine has revealed for the first time the presence of a number of known insect pheromones. This search has been facilitated by the use of a powerful new analytical technique, automated solid phase dynamic extraction (SPDE)/GC-MS, as well as by novel macros for enhanced and rapid comparison of multiple mass spectral data files from Agilent ChemStation . This chapter will focus on our methodologies and results, as well as on a comparison of SPDE and the more established techniques of solid phase microextraction (SPME) and stir bar sorptive extraction (SBSE). 

Mucignat Caretta, C., Caretta, A. and Cavaggioni, A. (1995) Pheromonally accelerated puberty is enhanced by previous experience of the same stimulus. Physiol. Behav. 57, 901-3. 

Exploratory experiments with dictyotene and suspensions of male gametes of E. siliculosus showed a significantly enhanced production of the 6-butylcyclohepta-2,4-dienol and its isomers. This indicates that a biological degradative pathway does exist and that this pathway follows the same oxidative sequence as the abiotic route. However, final conclusions about the biotic contribution to the pheromone transformation cannot be drawn before careful analysis of the degree of enantioselectiv-ity of the biotic reaction. 

An important subset of pheromone-specialist PNs in male M. sexta receives input from both component A and component B input channels, described above, but the physiological effects of the two inputs are opposite (72). That is, if antennal stimulation with component A leads to excitation, then stimulation with component B inhibits the intemeuron, and vice versa. Simultaneous stimulation of the antenna with both components A and B elicits a mixed inhibitory and excitatory response in these special PNs. Thus these neurons can discriminate between the two inputs based upon how each affects the spiking activity of the cell. These PNs also respond uniquely to the natural pheromone blend released by the female these pheromone specialist neurons have enhanced ability to follow intermittent pheromonal stimuli occurring at natural frequencies of 10 stimuli per sec (77). 

GABAa receptors. Furthermore, applied GABA hyperpolarizes the post-synaptic neuron, and this response can be blocked reversibly by bicucul-line, indicating that bicuculline directly blocks the GABA receptors. Such GABAergic synaptic transmission is essential to the enhanced ability of the specialized AL PNs to follow intermittent pheromonal stimuli (77). 

Two related scarab species produce ethyl 4-methyloctanoate 78 (Scheme 8) as an aggregation pheromone the African rhinoceros beetle Oryctes monoceros [170] and the coconut rhinoceros beetle Oryctes rhinoceros [171, 172]. The latter is readily attracted to the racemate. Its secretion was found to contain the free acid as well as ethyl 4-methylheptanoate [ 171 ]. Similarly to other cases, the attractiveness of ethyl 4-methyloctanoate is enhanced by host compounds, i.e. coconut wood [173]. The date palm fruit stalk borer, Oryctes elegans, uses 4-methyloctanoic acid as a male produced pheromone [174]. Structurally... 

The biological activity of the banana weevil pheromone and those of related palm weevil species is strongly enhanced by host plant volatiles [399,417-419]. 

A component of the vaginal secretion, dimethyl disulfide, was found to be the major sex attractant of the golden hamster [ 59 ]. Volatile alcohols, fatty acids and, interestingly, dimethyl trisulfide in the secretion do not appear to enhance the attractancy of the secretion [60]. However, proteins in the mass range of 15-16 kDa that are present in the vaginal secretion act as a mounting pheromone [61]. No comprehensive chemical characterization of the semiochemical secretions of golden hamsters has yet been undertaken. 

Mice are able actively to seek or avoid priming pheromones that modulate their ovarian cycle and onset of puberty. Peripubertal female mice avoid the urine odor of adult males, known to accelerate puberty in females, and are more attracted to the odor of grouped adult females. This behavior is particularly effective because the active space of the (almost) non-volatile male pheromone is small, and prolonged exposure is required for the effect to occur (Coppola and O Connell, 1988). Likewise, prepubertal female mice do not urinate near urine marks of adult males, while grouped, estrous, and diestrous adult females do. Such behavior may help young females to avoid exposure to male odors until they reach puberty. This way they would be protected from mating too early, and their eventual reproductive success would be enhanced (Drickamer, 1989a). 

Most goats in the northern hemisphere breed in fall and winter. Decreasing day length stimulates ovarian cycles. In addition to photoperiod, male pheromones stimulate pulse frequency of LH in the blood plasma of females (Martin etal., 1986). This not only enhances the seasonal onset of ovarian function, but also synchronizes breeding and subsequent lambing. 

De Fraipont, M. and Sorensen, P. W. (1993). Exposure to the pheromone 17cc,20 /3-dihydroxy-4-pregnen-3-one enhances the behavioral spawning success, sperm production and sperm motility of male golddsh. Animal Behaviour 46,245-256. 

Scott, A. P., Liley, N. R., and Vermeirssen, E. L. M. (1994). Urine of reproductively female rainbow trout, Oncorhynchus mykiss (Walbuam), contains a priming pheromone which enhances plasma levels of sex steroids and gonadotropin II in malts. Journal of Fish Biology 44,131-148. 

The sex pheromone of the female dogwood borer, Synanthedon sci-tula Harris (Lepidoptera Sesiidae), was identified as a blend of (Z,Z)-3,13-octadecadienyl acetate(a), (Z,Z)-2,13-octadecadienyl acetate (b), and E, Z)-3,13-octadecadienyl acetate (c) in a ratio of 88 6 6 respectively. Further analysis indicated that (a) was the major component and was attractive by itself A mixture of (a) and (b) enhanced the activity. Attraction was strongly antagonized by the addition of (Z,Z)-3,13-octadecadienyl acetate. 

The components of the sex pheromone from female nettle caterpillars Darna trima and Darna bradleyi (Lepidoptera Limacodidae) were identified. The compounds from D. trima were 2-methylbutyl-(A )-7,9-decadienoate (A) and ( )-2-hexenyl ( )-7,9-decadienoate (B) and from D. bradleyi were identified as methyl (T)-7,9-decadienoate (C) and isobutyl (.ff)-7,9-decadienoate (D). In Malaysia, (5 )-2-methylbutyl- E)-7,9-decadienoate in combination with B proved to be essential and synergistic pheromone components for attraction of males in field tests. (i )-2-methylbutyl- ( )-7,9-decadienoate had no behavioral activity. Compound D singly attracted male D. bradleyi, but the addition of C and D in a ratio of 1 10 significantly enhanced attractiveness of the bait. ... 

The female sex pheromone of a mite, Rhizoglyphus rohini Claparede (Astigmata Acaridae), was identified as a-acaridial [2(T )-(4-methyl-3-pentenylj-butenedial], which stimulated males and enhanced male mounting behavior. This was the first time that two pheromones (the alarm pheromone neryl formate and the sex pheromone a-acaridial) have been... 

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