Dominant males

The prophecy on semiochemical systematics in the headline quotation at the start of this chapter remains just that — an intriguing speculation. Some single-component chemosignals do turn up as apparently the main active compound in a complex secretion. In male gerbils (Meriones) one volatile, phenylacetic acid, appears to represent the dominant male state (Thiesen, 1974). Individuality must be added by further components — dietary or variable sebum constituents in this case. Indeed, amongst mammals and some reptiles, complex mixtures seem to be the norm very few taxonomically relevant examples have emerged. 

Parga, J.A. (2006) Mulitiple mating and female mate choice in Lemur catta does it pay to be a dominant male Am. J. Phys. Anthropol. 42 supp, 144—144. 

After dominance is established, the dominant male occupies a "preferred" large shelter which becomes a focus of social interactions. Mature, premolt females visit frequently (31,32). For cohabitation and subsequent mating, females in naturalistic aquaria chose the dominant male over subdominants (31). In choice tests females prefer larger dominant males (23). Females make these behavioral decisions both from a distance and at the shelter entrance. Discrimination by females is lost when males are catheterized and can be regained when that male s urine is artificially released near the male (23). Thus, male urine cues for female choice are implied but have not been identified. 

Common to urine of dominant and subordinate males Exclusively in urine of subordinate males Exclusively in urine of dominant males... 

There are a variety of constitutively active mutations in the gene encoding the LH receptor. These variants result in gonadotropin-independent disorders such as testotoxicosis and familial male precocious puberty (FMPP) (91). These disorders are inherited in an autosomal dominant, male-limited pattern (92,93). 

Dominance status information, coded in whole-body odor, can travel between animals in an air stream. When exposed to the odor of a familiar, dominant male, the sugar glider, P. breviceps, increases cardiac and respiration rates within 10 minutes, and levels of glucose and catecholamine in the plasma rise after 30 minutes (Stoddart and Bradley, 1991). 

In other rodents, subordinate males also smell scent marks quite often and so keep informed on the presence, status and activities of higher-ranking group members. For instance, dominant males of the hispid cotton rat, Sigmodon hispidus, urine mark more than subordinates. The social status of the male urine donor affects the response of other males to the odor. The response of a reproductive female to feces of either sex depends on her dominance status (Gregory and Cameron, 1989). 

Rabbits, 0. cuniculus, chin-mark (Fig. 6.4) near their warren entrances and at boundaries to neighboring groups. Only the dominant male marks. This has been demonstrated by comparing gas chromatograms of the chin gland... 

Dominant males of the European rabbit, 0. cuniculus, have 2-phenoxyethanol in their chin gland secretion. Behaviorally subordinate males lack this compound. When a subordinate becomes dominant after removal of the originally dominant male, 2-phenoxyethanol starts showing up in his secretion. The perfume industry uses this compound as a fixative. Rabbits perhaps also employ this... 

In mice, urine is the main source of social odors. Wild house mice (M. domcsticus) families over time build bizarre small posts of solidified urine by repeated marking (Hurst, 1987 Fig. 6.13). A mouse family is habituated to its own background odor, which permeates its living area. The ubiquitous family odor is dominated by the odor of the dominant male and identifies the home area to residents as well as non-residents. (When the author trapped 26 deer mice over... 

The function of the flank gland of the golden hamster, Mesocricetus auratus, is not clear but it appears to be involved in signals of sexual and social status and familiarity of the male to the female. Sexually receptive females spend more time near flank scent marks of intact males than castrates, or clean controls. They also stay longer near marks from familiar males than novel males. Finally, these females spend more time near marks of dominant males (compared with subordinate males) (Montgomery-St. Laurent etal, 1988). 

Dimethyl-2-ethyltetrahydrofuran-2-ol 6-Hydroxy-6-methyl-3-heptanone FIGURE 8.2 The active compounds in the urine of dominant male mice. 

Rozenfeld, F. M. and Rasmont, R. (1991). Odour cue recognition by dominant male bank voles, Clethrionomys glareolus. Animal Behaviour41,839-850. 

Make sure that stud males are caged alone for several weeks prior to caging with females to prevent suppression of testosterone by dominant males in the same cage, which lowers plugging efficiency. 

In subsequent studies the simple terpenes EJi-a- and -/3-farnesene (3 8 and 39, respectively) were identified in dominant male urine.128 These odoriferous terpenes had long been recognized as components of cues released by a variety of other organisms (red fire ants, aphids, wild potato plants, fruit flies, and springbok). Because neither was detected in male bladder urine, attention was focused on the preputial glands as the source. Volatile components from dissected, fat-free preputial glands of dominant male mice were, again, preconcentrated on Ten ax. Subsequent GC analysis readily allowed identification of known 37 and 38. None of the earlier two components 36 or 37 was observed in the preputial volatiles, but both were present in the bladder urine of the same animals. 

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