Identifying a spider with two dots on the back that looks like a weaver ant is not as easy as it seems. Because there are minimum two species described:
Both crab spider species (familily Thomisidae with over 2000 species!), A. lineatipes (Singapore and Indonesia) and A. forticeps (China to Malaysia) are described as Weaver ant-like. Not sure how much they respect the boarder from Singapore to Malaysia, I just use lineatipes for our spider. Keep in mind Singapore is right in the middle of their distribution. They also look the same when looking at pictures. Described were both spiders by Octavius Pickard-Cambridge, 1901 resp. 1873, so I would trust that he did not describe the same species twice, though it was 28 years later. I’m not sure whether both are valid species, nor if we have both in Singapore.
Make sure you know your weaver ants before reading this!
Imagine you are a tiny spider, not even as big as the weaver ant, and all alone. How would you catch an ant, without being caught by other ants of the pack? Difficult! But Amyciacea lineatipes knows how. They do not only look like weaver ants, they feed on them.
The amazing point is the technique they use to catch them. Once they caught one, they jump off the leaf or branch, dangling on a thread of silk while killing the ant. Doing so, they are safe from other ants attacking! How cool is that, and how smart. For sure it is still challenging to deal with that one prey, which is for sure still a very defensive snack. Often the spider is half the size of the ant.
Looking like an ant does not mean eating ants, but in this case it is true. Read here how another ant mimicking spider does not catch weaver ants, but takes the larvae they carry. Seems a bit mean! Our carb spider though takes the worker itself.
Myrmecomorphy by the way is the scientific term for ant mimicry. There are about 2000 species of ant-mimicking arthropods described so far, and I have found at least 5 (spiders, wasps, even a caterpillar), I think it is worth an own gallery soon!
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