Pheromone activity, effects

Females begin to emit pheromone 9 or more days after the adult molt (Bodenstein, 1970 Takahashi et al., 1976 Hawkins and Rust, 1977), but clearly, this is variable and temperature dependent. The attractancy of gut extracts made on the first day after the imaginal molt corresponds to that of 0.1 ng ( )-periplanone-B (Sass, 1983). During the next 20 days, the effectiveness of both fractions of the sex pheromone (periplanone-A and periplanone-B) in behavioral assays increases 100-fold and remains high for at least the next 45 days. Collection of airborne pheromone with Tenax followed by behavioral assays showed that periplanone-A and periplanone-B were released by 10-25-day-old females in equal amounts, equivalent to 0.6 ng periplanone-B per female per day (Sass, 1983). Yang et al. (1998) confirmed an increase in pheromone activity in the early adult but showed a decline in pheromone between days 20 and 30. 

Subchev M. A., Staminivora L. S. and Stoilov I. L. (1985) Effect of cis- I -hcxadecenol and its derivates on the pheromonal activity of cis- I -hcxadcccnyl acetate to males of three noctuid species (Lepidoptera Noctuidae) in fields. Ecology 17, 56-61. 

Monitoring the purification of the first pheromone (Ca. hemipterus) by wind-tunnel bioassay was complicated by a synergistic relationship with food odors. It was difficult to demonstrate the activity of the pheromone once it became chromatographically separated from the food scent that was also present in the volatile collections (Bartelt et al., 1990a). Consequently, food scent, or a synthetic version of this, was routinely added to each bioassay treatment, and the food scent itself became the control when pheromone activity was being evaluated. A variety of esters, alcohols, and other compounds were found to syner-gize the pheromone of Ca. hemipterus (Dowd and Bartelt, 1991). Synergistic effects were seen with all the species. 

Male palaearctic bees (Andrena wilkella) in Sweden produce 2,8-dimethyl-l,7-dioxaspiro[5.5]undecane (88, Figure 4.34) as their pheromone. Its (25, 6R,83 )-isomer is pheromonally active, while the opposite enantiomer (2R,6S,8R)-88 is inactive.63 There are six stereoisomers of 2,8-dimethyl-1,7-dioxaspiro[5.5]undecane (88), three as shown in Figure 4.34 and their opposite enantiomers. Due to the oxygen-anomeric effect, (2S,6R,8S)-88 and its opposite enantiomer are the stable isomers. 

Bioassay of our pure stereoisomers of 104 was carried out by Schal and coworkers in the USA, and indeed all of them were pheromonally active. More remarkably, the natural pheromone (35,1 l.S )-104 was the least effective of the four isomers at eliciting courtship responses in males.104 The cockroach produces the least active (35,115)-104 due to the stereochemical restriction in the course of its biosynthesis. Nature does not always provide the best thing. 

In June 1980, I was talking and tasting good wine at Professor Wittko Francke s home near Hamburg, Germany. We talked on olean, and noticed its axial chirality. We became interested in knowing the effect of axial chirality on its pheromone activity. After my return to Tokyo, we started the synthesis of olean enantiomers, as shown in Figure 4.75. 

Young honey bee queens produce a repellent pheromone that effectively tranquilizes workers that may interact antagonistically with these virgin females (16). The active compoimd, o-aminoacetophenone, is a minor component in the anal exudate that is discharged by the molested queens ( ). This compound is also a defensive allomone of an ant species (34), raising the possibility that it may possess general deterrent activity for arthropods. 

Monti-Bloch, L. and Grosser, B. I. (1991) Effect of putative pheromones on the electrical activity of the human vomeronasal organ and olfactory epithelium. J. Steroid Biochem. 39, 573-582. 

Coureaud, G., Langlois, D., Perrier, G. and Schaal B. (2003) A single key-odorant accounts for the pheromonal effect of rabbit milk Further test of the mammary pheromone s activity against a wide sample of volatiles from milk. Chemoecology 13, 187-192. 

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