Myrmecomorphy

November 19, 2017

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Above: I’m just an ant! Leave me be! (It’s a mantis actually)

Just like how humans mimic their idols, many animals mimic other animals. However, unlike humans, animals mimic each other to survive in the tough wilderness, be it to hunt their prey (aggressive mimicry), to protect themselves from predators (defensive mimicry) or to increase their chances at reproduction (reproductive mimicry). Myrmecomorphy, or ant mimicry is common among various insects and spiders.

Now, you may ask: “Why would anyone want to mimic an ant when they are tiny and not well camouflaged?”. Well, as their ubiquity can attest to, ants are perhaps the most successful of insects. These eusocial insects work together impressively to attain goals not achievable by any individual insect. They build their nests quickly and tirelessly, they hunt for prey or forage for food constantly, they defend their nests and queen fiercely, and they ravage new territories and wage wars against other ants. Individually, most ants are known to have an aggressive temperament with a powerful sting, and are known to secrete distasteful formic acid when attacked or stressed. This combination of offense and defense makes them insects not to be trifled with despite their small size. Additionally, since most ants attack in a group, anyone who trifles with them will likely be in for a rough time. As someone who has been bitten countless times by weaver ants (Oecophylla smaragdina), I can attest to the unpleasantness of getting attacked by ants.

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Above: A group of aggressive weaver ants (Oecophylla smaragdina) tending to aphids on an Ixora plant. These creatures do pack quite a punch!

There are many insects and spiders that mimic ants for defense. Since many would-be-predators that rely on sight would be hesitant to attack ants, these arthropods are protected from predation just by looking like ants. This is an example of Batesian mimicry, where a harmless species mimics a harmful or dangerous species to fool predators. Some arthropods mimic ants in their juvenile stage, only to lose their facade as they grow older. Examples of such arthropods include katydid nymphs (such as Eurycorypha sp.) and mantid nymphs (such as Odontomantis planiceps). Others mimic ants even as adults, such as various spiders (Myrmarachne spp.).

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Above: A juvenile Asian Ant Mantis (Odontomantis planiceps) with its ant mimicry.

 

Below: An older O. planiceps with its not-so ant mimicry.

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On the other side of the spectrum, many myrmecomoprhs are aggressive mimics, meaning they mimic the ants to prey on them. These are mainly spiders like the crab spiders Amyciaea lineatipes (found locally in Singapore) and Aphantochilus rogersi (from Central and South America). A blogger does seem to suggest that these spiders (or at least the latter) are both Batesian and aggressive mimics at the same time, since ants primarily make use of chemical cues to communicate and mimicking appearances alone would likely have a minimal effect in fooling ants.

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Above: Myrmaplata plataleoides, a Salticid that mimics weaver ants. The above pic is of a female.

Below: A male Myrmarachne cornuta, a very common ant mimicking Salticid found in Singapore. I have even observed it in Bishan Park’s butterfly garden. 

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There are also Wasmannian mimics of ants, which are those that mimic the chemical language of ants. An example is the sneaky jumping spider Cosmophasis bitaeniata, which does not resemble weaver ants closely, but uses its ‘perfume’ to become accepted by the aggressive ants. The spider is thus able to seek protection from predators by staying close to the ants, all the while doing nothing to help the cause of the ants. What a free-loader!

Personally, I have only spotted Batesian myrmecomorphs in my trips around Singapore so far. I first came across one on St John’s Island. The juvenile mantis (Odontomantis planiceps) immediately became one of my favourite animals, and myremcomorphy was introduced to me. The first time I noticed an spider myrmecomorph was in Zhenghua Forest Trail, and it was a male Myrmarachne maxillosa. I was undoubtedly excited as I took several (not too clear) photos. I observed it as it scrambled around a leaf while avoiding the true ants. Since then, I have noticed many more ant-mimics in the forested and even the more urban areas of Singapore. They are not necessarily rare, just that most are often overlooked as ants, showing that their clever disguises are doing their job.

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Above: My first ever encounter with an ant-mimicking spider. This is a male Myrmarachne maxillosa. Could not get a clearer photo because the conspider wouldn’t stop moving. 

The ant mimics can often be distinguished from the true ants by their behaviour. Most of them will not be in close proximity to an ant trail, and the non-aggressive mimics will tend to avoid contact with the ants. I have also observed that the ant mimics are non-confrontational in the face of a larger animal, like humans; whereas the ant mimic Myrmaplata plataleoides will scurry away at the sight of approaching humans, the real weaver ants will attempt to intimidate approaching humans.

Looking at these amazing creatures (seriously how can anyone not be fascinated by them?), I just want to photograph and observe more of them for myself, especially the ones that I have not come across yet (or perhaps might have mistook for ants, those darn clever cons).

My personal bucket list of myrmecomorphs that can be found in Singapore that I haven’t come across that I want to photograph:

1) Amyciaea lineatipes, the ant-mimic crab spider, an aggressive myrmecomorph

2) Macroxiphus sp., specifically the nymph of this katydid, a Batesian ant mimic

3) Homodes bracteigutta, specifically the caterpillar of this Erebidae moth, a Batesian mimic of weaver ants (Note to self: look for its host plant, Clerodendrum inerme)

The next time you come across what may seem like an ant, look again. It may just be one of them clever myrmecomorphs!

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Above: Gotcha! An ant-mimicking sac spider (Castianeira sp.) that would probably be mistaken for a larger Polyrhachis ant by most humans. It is likely a Batesian mimic. 

 

 

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