J. S. Kennedy & T. E. Mittler wanted to investigate the nutrient content of plant phloem, the food of the aphids they studied. They developed a technique for collecting phloem using aphids. They allowed aphids to settle on a plant and begin feeding on the phloem. The aphid could be quickly decapitated in a manner that would leave the stylets of the aphid firmly implanted in the phloem. The phloem, under pressure from the transport process of the plant, continued to flow from the end of the stylets for several days. J. S. Kennedy & T. E. Mittler first published their technique in a Letter to Nature in 1953* and noted that plant physiologists might find the technique useful. The technique has been refined, modern tools such as lasers are used to cut the aphid stylets, but the basic technique is still in use by plant physiologists today.
J. S. Kennedy & T. E. Mittler. A Method of Obtaining Phloem Sap Via the Mouth-parts of Aphids. Nature:171, 1953. p 528.