Sheep blowfly research. III. Studies on the olfactory reactions of sheep blowflies

Abstract

1. In a search for olfactory attractants to sheep blowflies, tests were conducted by means of an olfactometer in the laboratory, while some substances were tested under field conditions in traps. 2. Certain alcohols, aliphatic acids, esters, organic sulphides and inorganic salts were tested in the laboratory; boiled and unboiled solutions of sodium and potassium hydroxide were found to attract L. cuprina, while natural civet and musk ketone were weakly attractive. Sodium bicarbonate solution was repellent. Strong repellents are Dippel's oil, carvone, and linalool. 3. Preparations of suint were found in general to be unattractive. 4. The chemical treatment of meat bait by the addition of cystine, calcium carbonate, calcium sulphide, sodium carbonate, sodium sulphide and phenothiazine, enhanced its attractiveness. 5. Inoculation of meat bait with a mixed culture of bacteria from sheep's intestines increases attractiveness. 6. Fermenting baits, e.g., fish meal, pancreatin and egg, and addled eggs, proved to be attractive, but they were not so attractive as meat baits. 7. Some of the attractive substances of beef bait were extracted by ethyl ether, but these chemicals were not isolated or identified. A portion of these attractive substances were apparently removed from the ether solution by potassium hydroxide solution. 8. Flowers of Stapelia flavirostris are strongly attractive to, and stimulate oviposition by Lucilia cuprina. Distillates of these flowers were found to be attractive but no chemicals were isolated or identified. Further investigations on the chemistry of these flowers are recommended. 9. No blowfly attractant superior to chemically treated beef bait has been found.