Effect of methyl phenyldiazenecarboxylate (Azoester) on the feeding behaviour of blood sucking invertebrates

A NUMBER of stimuli controls the feeding behaviour of haematophagous organisms. Four steps in the feeding behaviour are recognized: (a) attraction to the host and settling; (b) probing; (c) sucking and (d) withdrawal. Various stimuli (visual, thermal, humidity, chemical) are involved in the first three steps. The stimulus for the fourth (cessation of feeding) has not been elucidated, but may well involve sensing a rise in pressure on distension of the abdomen as in the bug Rhodnius¹ or in the medical leech². We have investigated possible means of interfering with the chemical stimuli which induce feeding in blood sucking organisms, with the aim of developing an antifeeding agent that will protect people from the ill effects of these organisms. We chose organisms in which the stimuli that induce feeding on blood have been identified so that we were able to work in controlled conditions, using chemical stimuli rather than a host to induce feeding.