On the Sensitivity of the Chemoreceptors on the Antenna and Fore-tarsus of the Honey-bee, Apis Mellifica L

The experiments were designed to determine the critical dilution of sucrose which would elicit a response when brought into contact with the antenna, as well as to find out the dilutions that would obtain a like response on the fore-tarsus. The criterion of response was the complete extension of the proboscis. Minnich (1921-32) has demonstrated that the tarsal joints of many insects (certain butterflies, muscid flies and bees) possess contact chemoreceptors which serve as organs of taste. Minnich used insects with extensible mouthparts, and recorded a response on the extension of these organs after the stimulus had been given. The sensitivity of the contact chemoreceptors in certain butterflies is such that they respond to a 1/6400 M solution of saccharose though at the same time showing no response to distilled water. Verlaine (1927) disagreed with some of Minnich's results with Pieris rapae. He failed to obtain the regular extension observed by Minnich and accounted for many of Minnich's results in terms of stimulation by water vapour, tactile stimuli dependent upon viscosity, and mechanical stimuli brought about during the course of the treatment. Since all Minnich's results were based on response, only after water had failed to elicit a response, water vapour cannot be regarded as the cause of the response. It is on this assumption that the whole technique rests. Nor can the viscosity of the solutions be an influencing factor, since, as Minnich points out, the order of effectiveness of the solutions as tarsal stimuli was: