Scratch My Back: See How Ants And Caterpillars Help Each Other In Peru’s Dense Rainforest

Entomologist Aaron Pomerantz discovered something bizarre happening on tree bark in the Amazon rainforest in Peru. Instead of tree damage, a huge fungal growth, or a brand-new species, Pomerantz discovered an interaction among three life forms that no one had seen before.

Symbiosis on a Microscale

The tree bark fostered hundreds of tiny yellow spheres, KCET reports. Very small caterpillars munch away at the spheres, but that’s not what’s unusual. These caterpillars hired their own bodyguards in the form of ants, who eat sugary secretions that come out of the caterpillars.

These ants keep possible predators and parasites away so the caterpillars can leisurely enjoy their food. This symbiotic relationship shows that every living thing depends on other life forms up and down the food chain, even on a very small scale.

Pomerantz calls this special symbiotic relationship mymecophily, or “ant loving.” After sending pictures off to other scientists, Pomerantz found a complex relationship among the tree, yellow buds, caterpillars, and ants.


The small yellow buds are actually a rare parasitic plant that lives inside the tree. Once a year, the plant produces hundreds of tiny yellow flowers, according to Entomology Today. The caterpillars, juvenile forms of the butterfly Terenthina terentia, or Terentia hairstreak, eat the yellow flowers.

Ants feast on the sugary secretions of the caterpillars. Liquid comes out of a special organ called the dorsal nectary organ, and the ants, which are roughly the same size as the caterpillars, drum on the backs of the caterpillars to signal it’s time to eat. Each caterpillar secretes a small drop of a substance that contains sucrose and amino acids. The ants readily lap up this substance — a unique form of symbiosis.

Until Pomerantz witnessed these caterpillars eating, no one knew how the hairstreak lived or ate. This species of butterfly lives in the Peruvian and Brazilian Amazon, says Learn About Butterflies. Adult versions of this species eat nectar from flowers. However, the caterpillars make their own nectar as a way to create an army of bodyguards.

Learn about how Peru is helping preserve this symbiotic relationship by checking out their huge new national park!.

Protect the Planet

Help preserve vital habitat at The Rainforest Site for free!