Mutualism: Effects of Ants on Aphids, Their Predators, and Host Plants

Abstract

Aphids extract sap from plant stems, specifically the phloem tissue. They excrete “honeydew” which still contains plant sugars.\rAnts collect this honeydew, often by “milking” the aphids, and use it as food. In return, they protect the aphids against\rpredators. Ants prey on predators of aphids such as ladybird beetles (coccinellids), thus defending the aphids. Ants also\rshelter aphids by taking them or their eggs into their nests during inclement seasons. In a sense, ants herd aphids like cows.\rFurthermore, without removal of honeydew, aphid colonies become fouled.