Chemical signals pheromones

The external cuticle of insects is covered by a waxy layer composed of mixtures of hydro-phobic lipids that include long-chain alkanes, alkenes, wax esters, fatty acids, alcohols, aldehydes, and sterols. The primary purpose of this layer is to maintain water balance and prevent desiccation, as described in Chapter 6, but many of the cuticular lipid components have important secondary roles as intraspecific contact chemical signals (pheromones). These roles include species and sex recognition during reproductive interactions, and nestmate recognition and other colony organization functions in social insects. Thus, these compounds are essential mediators of insect behaviors. Cuticular compounds are also exploited by parasitoids and predators as interspecific contact cues (kairomones) to aid in host location. 

Information about sex, reproductive condition and social status is all coded in chemical messages secreted or excreted by members of various species (see contributions in the three previous publications in this series) In addition to their information content, chemicals released by animals also affect physiological responses, and the vomeronasal organ seems to be particularly involved in reception of these chemical signals (pheromones). Many pheromonal effects depend on an intact vomeronasal system (see Table 1) they do not occur or are much reduced if the vomeronasal system of the recipient animal is rendered non-functional. Indeed, the organ has been implicated in the control of reproduction, especially in the onset of sexual... 

Bronson F. and Coquelin A. (1980). The modulation of reproduction by priming pheromones in house mice speculations on adaptive function. In Chemical Signals in Vertebrates 2 (Miiller-Schwarze D. and Silverstein R.M., eds.). Plenum, New York, pp. 243-266. 

Duvall D. (1986). A new question of pheromones Aspects of possible chemical signalling and reception in the mammal-like reptiles. In Ecology and Biology of Mammal-like Reptiles (Hotton N., et al., eds.). Smithsonian Institution, Washington D.C., pp. 219-238. 

Feldhoff R.C., Rollman S.M. and Houck L.D. (1999). Chemical analysis of courtship pheromones in a Plethodontid Salamander. In Advances in Chemical Signals in Vertebrates (Johnston R.E., Miiller-Schwarze D. and Sorenson P., eds.). Kluwer, New York, pp. 117-126. 

Novotny M., Jemiolo B. and Harvey S. (1990). Chemistry of rodent pheromones, molecular insights into chemical signalling in mammals. In Chemical Signals in Vertebrates 5 (MacDonald D. and Natynczuk S., eds.). Oxford University Press,... 

Regier F. and Goodwin M. (1977). On the chemical and environmental modulation of pheromone release from vertebrate scent marks. In Chemical Signals in Vertebrates 1 (Muller-Schwarze D. and Mozell M.M., eds.), pp. 115-134. 

Indication of a sex attractant has also been obtained for the noctuid pupal parasitoid Diapetimorpha introita (Ichneumonidae). Antennae from D. introita males gave EAG responses to diethyl ether extracts of female head, thorax or abdomen. Antennae from females did not respond to this chemical signal and male extracts elicited no activity. This suggested the presence of an extractable female-produced pheromone, to which the males respond. While live females were able to attract males, extracts were not active. This may be due to very low levels of biologically active material in the extracts [57]. 

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). 

Compared to the large number of chemical signals identified in insects, only a small number of proven mammalian pheromones are known, two of which have been identified in elephants (Albone 1984 Brown and Macdonald 1985 Wyatt 2003 Burger 2005). Female Asian elephants (Elephas maximus) release a... 

Goodwin, T.E., Brown, P., Eggert, M., Evola, M., House, S., Morshedi, G., Weddell, M., Chen, J., Jackson, S.R., Aubut, Y., Eggert, J., Schulte, B.A. and Rasmussen, L.E.L. (2007) Use of automated solid phase dynamic extraction (SPDE)/GC-MS and novel macros in the search for African elephant pheromones. In J. Hurst, R. Beynon C. Roberts and T. Wyatt (Eds.), Chemical Signals in Vertebrates 11. Springer Press, New York, pp. 20-29. 

Houck, L.D. 1986. The evolution of salamander courtship pheromones. In D. Duvall, D. MiHler-Schwarze and R.M. Silverstein. (Eds.) Chemical Signals in Vertebrates, Vol. IV Ecology, Evolution, and Comparative Biology. Plenum Press, New York. Pp. 173-190. 

Johnston, R. E. (1983) Chemical signals and reproductive behavior. In J. G. Vandenbergh (Ed.), Pheromones and Reproduction in Mammals. Academic Press, New York, pp. 3-37. 

Martfnez-Ricos, J., Agustfn-Pavon, C., Lanuza, E., and Martinez-Garcfa, F. (2007) Intraspecific comunication through chemical signals in female mice Reinforcing properties of involatile male sexual pheromones. Chem. Senses. 32, 139-148. 

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