How do ants protect certain orchids from insects that eat flowers?

Certain orchids utilize extrafloral nectaries—nectar-producing glands located on parts of the plant other than the flower—to attract ants and wasps.1

These insects provide a defensive service by patrolling the plant and scaring away or deterring various threats, including:

• Nectar robbers: Bees that might otherwise cut into floral tissues to steal nectar.1
• Herbivores: Insects such as grasshoppers, crickets, and caterpillars that would otherwise eat the flowers.1

This symbiotic relationship is particularly vital for certain orchid species that grow within ant nests, such as Coryanthes, Gongora, Epidendrum, and Schomburgkia. In these cases, the orchids are highly susceptible to damage from chewing insects if their resident ant populations are removed. It is important to note that while these ants protect the plant, they do not act as pollinators for the orchid.1