Pheromone secretion

Named bombykol, the sex pheromone secreted by the female silkworm moth has the formula C16H280 and the systematic name (10 ,12Z)-10,12-hexa-decadien-l-oJ. Draw bombykol showing correct geometry for the two double bonds. 

Contrary to the structure similarity of the pheromones secreted by taxonomical related moths, some differences are necessary for their sexual communication systems to play an important role in their reproductive isolation. In addition to further modifications of the various structures, diversity of the lepidopteran sex pheromones is generated by blending multiple components. Innumerable pheromone blends are based not only on combinations of different components but also on variations in the mixing ratio. A pioneer study with Adoxophyes spp. (Tortricidae Tortricinae) had already proposed this concept in the early 1970s. While the smaller tea tortrix (A. honmai) and the Japanese summerfruit tortrix (A. oranafasciata) had been considered to be variant strains with different host preferences in the same species, Tamaki et al. found that females of the former pest insect in the tea garden secreted Z9-14 OAc and Zll-14 OAc in a ratio of 7 4 but females of the latter defoliator of apple trees secreted them in a ratio of 13 4 [127,128]. Furthermore, two other components (Ell-14 OAc and MelO-12 OAc) were subsequently identified from the former species [129]. 

Figure 19.17 The biochemistiy and physiology responsible for penile erection. Sexual activity itself begins with a state of arousal that leads to erection. Arousal results in part from stimulation of the sense organs. The hypothalamus coordinates the sensations and activates the autonomic nervous system. Sensory nerves from the skin of the penis and other erogenous zones stimulate the parasympathetic system. This activates nitric oxide synthase and the resultant nitric oxide, via cyclic GMP, causes vasodilation of the arterioles. This increases blood flow through the corpora cavernosa which then expands producing an erection. Pheromones secreted by the female can stimulate the odour detecting system in the nasal cavity of the male (Chapter 12 and see above). Stress, however, activates the sympathetic system releases cyclic AMP which can result in vasoconstriction of the arterioles. Other factors that can interfere with an erection are physical fatigue and alcohol.

Snider and colleagues have developed the sequential ene reaction/thia-[2,3]-Wittig reaction which provide appropriately functionalized product 152 at allylic position on simple alkene 150 in two steps involving intermediate 151 (equation 87) . Thia-[2,3]-Wittig rearrangement was often utilized as a key step of natural product synthesis. Masaki and colleagues have demonstrated that the potassium enolate thia-[2,3]-rearrangement of aUyl sulfide 153 to 154 is useful for the synthesis of terpenoid diol component 155 of the pheromonal secretion of the queen butterfly (equation 88) . 

Lofstedt, C., Hansson, B. S., Petersson, E., Valeur, P. and Richards, A. (1994). Pheromonal secretions from gland on the 5th abdominal sternite of hydrodpsychid and rhyacophilid caddisflies (Trichoptera). Journal of Chemical Ecology 20 153-170. 

Muller, D. G. and Schmid, C. E., Qualitative and quantitative determination of pheromone secretion in female gametes of Ectocarpus siliculosus (Phaeophyceae), Biol. Chem. Hoppe-Seyler, 369, 647, 1988. 

There have been a couple of recent and excellent reviews of the ultrastructure of exocrine cells in general (Quennedey, 1998) and pheromone-secreting cells in social insects in particular (Billen and Morgan, 1998). This chapter attempts to survey the structural diversity of cells that produce sex pheromone in insects, particularly from a phylogenetic perspective, in part based on advances made... 

Many hemipterans have metathoracic scent glands (e.g. Oetting and Yonke, 1978), which may produce both allomonal and pheromonal secretions. For example, females of Alydus eurinus release an attractant pheromone from their metathoracic scent gland (Aldrich et al., 2000). The internal scent gland apparatus of alydids... 

Crossley A. C. and Waterhouse D. F. (1969) The ultrastructure of a pheromone-secreting gland in the male scorpion-fly Harpobittacus australis (Bittacidae Mecoptera). Tissuse Cell 2, 273-294. 

Iwabuchi K. (1986) Mating behavior of Xylotrechus pyrrhoderus Bates (Coleoptera Cerambycidae). III. Pheromone secretion by male. Appl. Entomol. Zool. 21, 606-612. 

Krool S. and Bauer T. (1987) Reproduction development and pheromone secretion in Heteromurus nitidus Templeton 1835 (Collembola Entomobryidae). Revue d Ecol. Biol, du Sol. 24, 187-196. 

Lane R. P. and de Souza Bemardes D. (1990) Histology and ultrastructure of pheromone secreting glands in males of the phlebotomine sandfly Lutzomyia longipalpis. Ann. Tropical Med. Parasitol. 84, 53-61. 

Yamamoto, M., Kiso, M., Yamazawa, H., Takeuchi, J. and Ando, T. (2000). Identification of chiral sex pheromone secreted by giant geometrid moth, Biston robustum Butler. 

Descoins, C., Lalanne-Cassou, B Frerot, B., Malosse, C. and Renou, M. (1989). Comparative study of pheromonal secretions produced by arctiid and ctenuchid female moths (insects, Lepidoptera) from the neotropical area. C. R. Acad. Sc. Paris Serie III, 309, 577-581. 

Frerot, B., Pougny, J.R., Milat, M.-L., Rollin, P. and Malosse, C. (1988b). Study of the pheromonal secretion of the tiger moth, Cymbalophora pudica (Esper) and enantioselectivity of its pheromonal perception. C. R. Acad. Sci. Paris, Serie III, 306, 157-160. 

Research on co-operation in insect societies mainly involves the study of this elaborate pheromonal communication system. Such studies generally involve three steps (1) identification of a putative pheromone secreting gland (morphological research), (2) study of the chemical composition of the secreted pheromones (gas chromatography-mass spectroscopy and NMR techniques) and (3) performing bio-assays with glandular extracts or artificially synthesised pheromones to establish their function. 

Research aims to study the structural organisation of pheromone secreting glands using light microscopy and transmission and scanning electron microscopy. 

Pheromones are a special type of compound secreted by the females of many insect species to attract the males for mating. One pheromone has the molecular formula C19H38O. Normally, the amount of this pheromone secreted by a female insect is about... 

Scientists have discovered that the butyl acetates are present in the so-called alarm pheromones secreted by animals, particularly insects. An alarm pheromone is a chemical secreted when... 

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