Pheromone Olfactory Communication

Nevertheless, it is possible that the giant-cells of Bufo may produce alarm substance since: 1) giant-cells are restricted to the systematic pheromone  group that has the alarm pheromone substance; 2) they do not open on the epidermal surface; and 3) they are present in very young tadpoles. We know little about the chemistry of the alarm substance of tadpoles. It seemed possible that the alarm substance might be identical with poisonous secretions of the toad.

However, extracts of parotic gland were tested and found to be less effective than skin extracts. Kulzer (1954) tested a series of substances, some of which were not effective while others produced some response. The effectiveness of bufotoxin and gama-bufotoxin (‘gama’ is Japanese and means ‘toad’) could not be distinguished from that of skin extracts. Two mg of each of the substances were diluted in two ml of water.

This solution retained its effectiveness after repeated dilution; 0.05 ml diluted in 500 ml water was still effective. Paper chromatograms of skin extracts showed similar distributions for both the alarm substance and the bufotoxin or gama-bufotoxin. In addition, absorption spectra of both substances were similar, but these results did not prove that both substances were identical according to

Human Pheromones Factors influencing the fright reaction

In contrast to the fish, tadpoles did not respond to fright movements of their pheromones. Kulzer (1954) placed two aquaria side by side and poured alarm substance in one tank. Only the tadpoles exposed to the alarm substance fled. In contrast to very young fish, newly hatched tadpoles immediately reacted to the extract of their companions which were the same age.

Before metamorphosis, the pheromonal intensity of the reaction became maximal. The tadpoles during metamorphosis responded to the alarm substance as long as they came to the feeding place in the aquarium according to

Also, the skin of small toads contained an effective alarm substance. It was demonstrated that neither food nor the duration of captivity has any influence on the responsiveness of tadpoles. In contrast to fish, the reaction of the tadpoles is more vigorous in warm water. Further, fish often become unresponsive to the alarm substance after a few tests, while this is not the case with tadpoles.

Normal responsiveness to alarm pheromones is present within a day after a test. The effect of the minnow (Phoxinus) alarm substance on tadpole schools (Bufo) and the effect of the tadpole alarm substance on minnow schools was studied by Kulzer (1954) and Schutz (1956) with negative reactions in both cases. Thus, the fright reaction of Bufo tadpoles is convergent with that of the Ostariophysi and Gonorhynchiformes. From existing evidence, we may assume that the fright reaction of anuran tadpoles is an important insurance against predation. The schooling tendency of the bufonid tadpoles becomes more understandable with this reaction. The alarm substance protects the shoal; it is logically of greatest value in species exhibiting social life.

The existence of pheromones olfactory communication in many, or more probably most, mammal species cannot now be doubted (Mykytowycz 1970, 1972; Ralls, 1971; inter alia), but little experimentation with, and analysis of, odors has yet taken place.


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