Recently, a new species of ant is being viralled in the news, especially in science news. The new species of ant (Colobopsis explodens) from Borneo, is said to be able to 'explode'!
When encountering a threat, the minor workers will raise their abdomen and bite on the attacking predator. When the larger predator (usually other larger ants) is being held down, these exploding workers will rupture and releases toxic secretions to kill or drive away predators. Other terms for this kind of action are Autothysis and suicidal altruism. These workers die in the process, sacrificing themselves for the greater good - to save their colony. This is similar to bees that dies after stinging.
The major workers of the colony are larger but they have a different role instead. These majors are tasked to guard the nest entrance, where they have modified heads to block the entrance from predators. Instead of giving them workers and soldiers with powerful mandibles or stings, evolution has decided to give them "suicide bombers" and "blockheads" instead.
When I read about this news a few days ago, I immediately recognize the red ant portrayed in the photos. I am used to seeing them on wooden railings and on tree trunks in my hometown - Tawau, Sabah (Malaysia). I easily notice them due to their attractive bright red color. I have only seen them in primary forests as they are arboreal and associate with big dipterocarp trees only. Little did I know about their defense mechanism before this.
Photographed in Tawau at 2016
There are at least 15 species of exploding ants found in Borneo (from a study in 2017), all were placed under the Colobopsis cylindrica species complex group, and now more specifically in the C. saundersi species complex group. Colobopsis (formerly Camponotus) saundersi is the most popular species of exploding ants, which was discovered back in 1889. Colobopsis explodens are quite abundant and easy to work with, that is why they are being studied in Brunei many years before finally being described as a new species.
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Photographed in Tawau at 2016
References:
National Geographic - 'Exploding Ant' Rips Itself Apart To Protect Its Own
https://news.nationalgeographic.com/2018/04/animals-ants-borneo-exploding-defense/
Gizmodo - New Species of ‘Exploding Ant’ Discovered in Borneo
https://gizmodo.com/new-species-of-exploding-ant-discovered-in-borneo-1825397505
ZooKeys - Colobopsis explodens sp. n., model species for studies on “exploding ants” (Hymenoptera, Formicidae), with biological notes and first illustrations of males of the Colobopsis cylindrica group
https://zookeys.pensoft.net/articles.php?id=22661
