Close quarter defence - Issue #83

Hello Explorer,
The past few weeks you will see that my Ficus collection is delivering quite a few interesting bugs and topics to discuss, and this week we return to another fig species and another interesting pest I came across. Before you ask, this pest is in the same category as the Blue-legged Sylvan Katydid (Zabalius ophthalmicus), it is welcome to stay until fully grown and then it will be evicted. Once again it falls in this category as it looks interesting, and I’m very curious to see what the adult looks like.
The pest I encountered is a Lasiocampidae or Lappet Moth Larva. I first spotted it on my Ficus sansibarica, and then lost it for a few days before finding it again on my Ficus bubu, where I managed to take some photos of it. This larva or caterpillar has very intense close quarter chemical defences that it delivers with extreme effectivity.
The caterpillar is covered with two different types of hair. The long hairs are setae and are mostly used for camouflage, helping them to blend in with tree bark, or with brown parches on the leaves. The short hairs are their close quarter combat defence mechanism, and they are known as Urticating hair.
Urticating hair are short, hollow, sharp hairs that are often connected to a venom cell or gland at the base of the hair. The urticating hairs also have a break point at the base of the hair, where it will naturally break off. Essentially these hairs are hypodermic needles filled with poison, ready and armed to be used in the defence of the caterpillar.
The venom that is delivered by moth and butterfly larvae differs greatly from species to species, and the effects of the venom can range from irritation to life threating conditions in humans as in the case of some Lonomia species from the Saturnidae (Emperor moths) family. The larva on my Ficus bubu has venom that only causes some irritation and itching.
These caterpillars do not actively shoot or eject the urticating hairs, they rather thrash about once they are grabbed by a predator. Their thrashing about stabs the urticating hairs into the predator, hopefully deterring it from seeing the caterpillar as a meal. Some birds like cuckoos have learned how to dislodge the urticating hairs from caterpillars by grabbing the caterpillar by the head and then rubbing it on a branch or on the soil. This allows the birds to actively hunt and consume these caterpillars without any ill effects.
When last did something like a hairy caterpillar astonish you this much? Have you ever experienced the effects of urticating hairs from a caterpillar by accident or by looking for trouble with a caterpillar? What was the affects you experienced? Would you like to learn more about insects’ self defence mechanisms in future?

If you would like to send me a message with your answers, feel free to do so on Instagram @abugmanslife or via email to [email protected].