Code of ant-plant mutualism broken by parasite.

Newly discovered Phyllobaenus beetles are parasites of a mutualism. Piper ant-plants in tropical forests provide lipid and protein-rich food cells and shelter for Pheidok bicornis ants while the ants remove small herbivores and vines from the foliage. In contrast to all other ant-plants, Piper ant-plants produce food bodies only when Pheidole bicornis is present in the plant. However, Phyllobaenus beetles can stimulate the plants to produce food bodies as if ants were present. The beetles then inhabit the plant, exploiting nest sites and food produced by the plants for ants. These beetles may also prey on ant brood, depriving the plants of resources and services provided by the ants.