Spider that mimics an ant

I found many caterpillars on a lemon plant. Resisting my temptation to take it home, I left them on the plant and planned to observe the different stages of the butterfly life cycle. After a few days I found that the caterpillars were missing. I searched the plant thoroughly but could not find them. In the next few days I saw another set of caterpillars. They too were missing after a few days. I wanted to solve this mystery. So I started to look for other insects and  birds which could possibly be feeding on the caterpillars.

I observed an ant which was moving around the plant. It looked like it was carrying something. On a closer look I found it was not an ant. It was a queer looking insect which was mimicking an ant. It was an ant-mimic spider, which I had seen in Karthikeyan Srinivasan’s blog. He says “Ant-mimic spiders, apart from the superficial resemblance to ants, also behave like them. They walk about continuously like ants. They also hold and wave their first pair of legs deceptively like the antennae of ants. And use the other three pairs of legs to walk about. Some ant-mimic spiders even smell like the ants they resemble. By mimicking ants, they stand a very good chance of being overlooked. Behaving and resembling the distasteful or dangerous ants reduces the chances of being eaten by predators.

Weaver ant carrying an ant

This spider’s id is Myrmarachne plataleoides, also called the Kerengga Ant-like Jumper. It mimics the Kerengga or weaver ant (Oecophylla smaragdina) in morphology and behaviour.

Have a look at these pictures by Santosh Krishnamurthy and Savitha Ravi of Ant mimic jumping spiders .

Do have a look in to this interesting post by Shyamal LakshmiNarayanan.

Unlike the weaver ants, M. plataleoides does not bite people, and indeed seems rather timid. Field experiments have proved that spiders can effectively reduce pest populations and the crop damage they cause. They feed on caterpillars, so the mystery of the disappearing caterpillars was solved. So if we  observe carefully enough in our surroundings we do encounter such delightful surprises.