Caterpillar Depends on Parasitic Plants and Nectar-drinking Ants

Entomology Today December 7, 2015 1 Comment

A caterpillar (Terenthina terentia) feeding on the yellow bulbs of a parasitic plant in the family Apodanthaceae, as an ant (Ectatomma tuberculatum) tends to it. Photo by Aaron Pomerantz.

Several months ago, Aaron Pomerantz was walking through the Peruvian rain forest and he found a tree with strange yellow bulbs protruding from the bark. In addition, he found caterpillars feeding on the yellow bulbs, and he noticed ants were interacting with the caterpillars in some sort of symbiotic relationship.

After doing some research, he learned that the yellow bulbs were actually a rare parasitic plant in the family Apodanthaceae. These plants live inside trees, and they burst out of the bark once a year and produce hundreds of yellow flowers.

The caterpillars turned out to be the larvae of a rare butterfly known as Terenthina terentia (family: Lycaenidae). This was the first time anyone had observed them eating the yellow plant bulbs. In fact, very little was known about how the butterfly lived until now.

The ants (Ectatomma tuberculatum) have a symbiotic relationship, known as myrmecophily, with the caterpillars. The caterpillars have evolved a special structure called the “dorsal nectary organ” which produces sugars and amino acids for the ants. The ants drink the nectar and in return act as bodyguards for the caterpillar.

Aaron is a field biologist at the Tambopata Research Center in Peru. You can follow him on Twitter at @AaronPomerantz.