Pheromonal systems in mammals
An interested reader can turn to any of a large number of recent reviews to nd up-to-date bibliographies concerning almost all facets of this broad subject: Bronson (1968, 1971); Bruce (1966, 1967, 1...
An interested reader can turn to any of a large number of recent reviews to nd up-to-date bibliographies concerning almost all facets of this broad subject: Bronson (1968, 1971); Bruce (1966, 1967, 1970); Cheal and Sprott (1971); Eisenberg and Kleiman (1973); Gleason and Reynierse (1969); Mykytowycz (1970); Ralls (1971); Schultz and Tapp (1973); Whitten (1966); and Whitten and Bronson (1970). Because of these extensive efforts, no attempt will be made in the present chapter to cite other than the latest or most relevant references.
Pheromones and reproduction in mice
When one considers the known pheromonal systems in mammals, undoubtedly the best documented and the most detailed is that encompassing the behavioral and physiological activities involved in reproduction in laboratory mice. More is known about priming pheromonal action in this species than in any other and, in addition, while field work involving mice is limited, considerable laboratory experimentation relevant to olfactory signals has been accomplished according to http://hartch25.weebly.com/our-marketing-blog/pheromone-trending
It is my intention in this chapter to use a detailed discussion of the interrelated phenomena pertaining to mouse reproduction as a model system for generalizing to other pheromonal systems and functions in other species of mammals. Before discussing the impact of pheromones on this particular set of events, however, we must first consider reproductive activities in the mouse in their entirety. Behaviorally we shall consider sexual behavior, maternal care, and aggression; the latter acting as a mechanism for population dispersal during the reproductive season.
Physiologically we shall be interested in puberty and the regulation of the infertile cycle as well as early pregnancy and maternal phenomena. A general text on reproduction (e.g.. Van Tienhoven 1968) can be consulted for details but, briey, house mice may show profound seasonal variation in their reproductive efforts in the field but breed throughout the year in the constant environment of the laboratory.
The pheromones mechanisms rely on the neural ramications of external cues such as photo- periodic changes or priming pheromones. Of particular interest are mechanisms at the level of the hypothalamus, whose activity regulates the secretion of the gonado- tropins, follicle-stimulating hormone (FSH) and luteinizing hormone (LH), from the anterior pituitary. With regard to non-pregnant, female mice, the secretion of gonadotropins is cyclic over a period of days (the estrous cycle); i.e., every few days the female ovulates and, for a period of hours at this time, will accept a male. There is strong circadian involvement since ovulation and mating almost always occur in the dark phase of the animal’s day. F SH and LH act in concert to promote ovum maturation, ovulation, and the production of the ovarian steroids, the estrogens and progesterone. In the male, secretion of the gonadotropins is relatively constant and the actions of FSH and LH are to maintain spermatogenesis and promote synthesis of testosterone and other androgenic steroids by the testes. Fig. 18.1 attempts to illustrate the entire complexity of behavioral and physio- logical events relevant to reproduction in both sexes of mice. The physical and/or social environment is perceived through sense receptors. Information thus collected is processed in the brain and certain cues or combinations of cues act _via the pheromone duct.
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ABOUT THE AUTHOR
Alexander P is a blogger taht studies pheromones.