Wynne-Edwards (1962), while discussing the problem of pheromonal homeostasis, i.e. self regulation of natural populations of animals, introduced the concept of ‘epideictic displays’. He s...
Wynne-Edwards (1962), while discussing the problem of pheromonal homeostasis, i.e. self regulation of natural populations of animals, introduced the concept of ‘epideictic displays’.
He suggested that these are necessary to allow animals to regulate their pheromone numbers and that the special sites on which animals deposit their scent are part of these displays. Most frequently these special sites for scent deposition are dung- hills. Many species of animals form dung-hills (Altmann 1969; Mykytowycz and Gambale 1969) which may not only be small discrete points, but in some species cover a considerable area, as for instance in the case of the hyena, Crocuta crocuta Kaup, up to a quarter of an acre (1012 m2 ).
The number of these pheromones also varies from species to species depending on their need to communicate. Some like vicuna and alpacas maintain only one or two within their range, while for hippos 84 dung-hills were counted on a 350 m stretch of river bank.
As these special places are centres of pheromone communication it is necessary that as many animals as possible, even non—members of the group, come to gather the informa- tion deposited on them. The fact that they are connected by paths which are often commonly used, assures regular access to them. To avoid a meeting between oppo- nents on these special sites a different time schedule may be employed. This happens with domestic cats and dogs.
It has been suggested that pheromone olfactory marking may function in some ways like railway signals. A fresh mark denotes ‘section closed’; less fresh, ‘proceed with caution’; old ‘go ahead’ (Leyhausen 1971). Naturally many other messages can be read simultaneously from the information sites. Learn more about pheromones at http://hartch25.weebly.com/our-marketing-blog/synthetic-pheromone-chemistry-in-bees
The behavior of wild rabbits influenced by sexual pheromones has been studied both experi- mentally and in natural populations (Mykytowycz and Gambale 1969; Mykyto- wycz and Hesterman 1970). It has been found that the dung-hills are visited by all the males, but only by a few of the females occupying the area. When at the dung-hills, the rabbits examine them olfactorily and deposit their own scent in the form of fecal pellets coated with secretion from the anal gland. Sometimes they also deposit secretion from the chin gland. It has been demonstrated that the fecal pellets produced for marking possess a stronger ‘rabbity’ odor than those produced at other times (Hesterman and Mykytowycz 1968). Rabbit dung-hills are not distri- buted randomly, but are concentrated at points which are most exposed to contact or invasion from neighbors. Some observations on the distribution of fecal pellets have been carried out also in holding pens. Four pens 3 x 4 meters in size were built of wire mesh, allowing visual and olfactory communication between adjacent pens. On the oors three separate zones were marked.
Counting the amount of pheromones deposited in these zones indicated that the removal of feces from the pens increased the deposition of fecal pellets, and that deposition was most intense in the zones bordering onto other pens.
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Alexander P is a blogger that studies pheromones.