If you are an entomologist or an insect enthusiast, it is highly probable that you like ants. It is hard not to be impressed with their diversity, abundance, complex social structure and behaviors, as well as their interactions with other organisms. Ants are everywhere and do almost anything you can think of. To most people however, ants could not be any less exciting. They are often seen as a generic insect, with a relatively uniform appearance. They always show up when unwanted, find their way into our homes, take refuge in dark and hard to reach corners, and steal our food.
I like ants. I think they are fascinating creatures. But every now and then I find myself talking people into looking beyond “that boring-looking ant”, to try and catch a glimpse of their busy life. It is not always easy to communicate ants to the public (which is why I praise myrmecologists – people who study ants for a living), however I find that it is quite easy in the case of one ant genus in particular: Cephalotes.
Cephalotes is a large genus of arboreal ants found in the neotropics. There are over 130 species, all inhabit tree hollows or utilize cavities in other plant tissues. Looking like they were designed by someone with overflowing imagination, they easily come off as cute. Their flattened head and armored body, often decorated with long sharp spines for protection, their thick legs and perfectly round abdomen, along with their matte color finish, give them the appearance of a plastic toy. In addition, Cephalotes ants move relatively slowly and cannot bite or sting, making them user-friendly. Can you ask for a more perfect ant?
They are commonly known as turtle ants, but also got the name gliding ants, thanks to their incredible ability to parachute from high in the canopy and land back on the trunk of their home tree. Their unique body structure and flattened legs allow them to slow down and change their course while falling (some spiders can do the same, by the way). In some species the soldier cast evolved a large head to function as a living door, plugging the entrance to the nest.
In regards to interspecific interactions, Cephalotes ants are often seen tending sap-sucking hemipterans such as membracids and small fulgorids to gain access to sugary secretions from those insects. They also act as the model in a mimicry complex, where crab spiders masquerade as the ants in order to sneak up and prey on them.
Did I mention they are cute? I have written before that you should never become too attached to insects you encounter in the field. And as much as I love the adorable Cephalotes ants, it is important to remember that there are many dangers lurking for them in the forest. During my recent trip in Colombia, I stumbled upon a Cephalotes nest in a tree outside my room. The ants were very active and did not present good photographic opportunities.
One of them however, stood out among the rest. There was something different about its behavior. This worker moved franticly in what appeared to be an aimless run. It did not follow the other workers, and seemed more interested in reaching a higher spot on the tree. I collected the ant for a closer look, and once I inspected her carefully I believe I found the culprit for her unusual behavior. This ant had a reddish abdomen, as opposed to the black abdomen of her sisters. The red color, coupled with erratic behavior suggests this worker has been infected with a parasite, a nematode worm.
The parasitic worm lives and breeds inside the body of birds, which spread the worm’s eggs in their droppings. The ants collect nutrients from the bird droppings (along with the eggs) and feed them to their larvae, where the worm matures. In order to complete its life cycle the parasite needs to return into a bird’s body, so it changes the host ant’s appearance to look like a ripe red fruit, and causes it to climb higher on the tree to become more accessible to hungry birds. As much unique character this worker ant might have had, the sad truth is that it was destined to die prematurely. And there was nothing I could do about it. There is a great lesson here – sometimes, the raw essence of nature is difficult to take in. We would like to see it as a peaceful place where all the animals and plants live together in harmony. But the reality is that nature is harsh. It is full of conflict, violence, disease, and death. And we must accept it as an integral part of the world we live in.
Cephalotes ants offer a great opportunity to peek into the life of a small insect and learn about its survival (as well as failure) in various habitats. Before I end this post, there is one thing I would like clarified – going back to their name, why did Cephalotes get the name turtle ant, whereas some leaf beetles were named tortoise beetles? Is there any justification for the turtle designation when it comes to the ants? After all, both insects are terrestrial. If there is an etymologist in the audience, maybe you can help the entomologist?