I once conducted a study on the Trabala caterpillar’s non-mutual symbiotic relationship or parasitism, which is located and found in SUMECO, North Sumatra, Indonesia, at an altitude of 312 meters above sea level.
Because plants have mobility limitations, they must devise a defense strategy to protect themselves when attacked by herbivorous insects. When herbivorous insects such as caterpillars eat their leaves, the wound on the leaf will stimulate a transduction signal to produce volatile compounds such as terpenoids.
These compounds will evaporate into the air, attracting predatory or parasitoid insects that will seek out caterpillars as live hosts to lay their eggs; this is what we call parasitism at work in the Leuser ecosystem. In addition, other volatile compounds will also be responded to by other plants as a form of indirect resistance to other herbivores and insects that may attack them.
“I would love to say the tale of this extraordinary biological process could be titled “The Enemy of My Enemy Will Kill My Enemy.” That’s how we should say it!” Bobi Handoko.
An observed Trabala caterpillar in the picture, which has been infested with pupae of Cotesia flavipes was found in SUMECO garden. Parasitoid larvae develop by feeding on their host’s body. The parasitoid phenomenon in this case is a common thing that happens between Trabala pallida and Cotesia flavipes and is also known as natural selection.
Technically speaking, this parasite is categorized as an endoparasitoid because the parasites live and feed on the host’s body until the host dies. Cotesia flavipes is a species complex that is always found in biological pest control processes. In my observation area, I saw Cotesia flavipes flying several times.
The picture above shows a dead Trabala three weeks after being parasitized by Cotesia flavipes. The young wasps will hatch from eggs 12 to 16 days after oviposition; they fly about 4 days later.
It has also been observed that this process is extremely vulnerable to the birds that may feed on them due to the spread of volatile compounds such as terpenoids, for which a long evolutionary process has trained birds to recognize the spread of these compounds in the air.
