Tomato plants attacked by small mottled willow moth caterpillars release chemicals with turn these caterpillars into cannibals. This plant induced caterpillar cannibalism benefit tomatoes in two different ways. Firstly, cannibalism directly reduces vegetarian caterpillar abundance. Secondly, cannibalistic caterpillars eat significantly less tomato leafs.
https://www.nature.com/articles/s41559-017-0231-6
https://www.nature.com/news/plants-turn-caterpillars-into-cannibals-1.22281