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During Quarantine, an Entomologist Takes a Closer Look at a New Invasive Ant Species

P. alluaudi forager scouting a plant

A Plagiolepis alluaudi forager scouting a plant infested with mealybugs. (Photo by Thomas Chouvenc, Ph.D.)

Thomas Chouvenc, Ph.D.

Thomas Chouvenc, Ph.D.

By Thomas Chouvenc, Ph.D.

In 2017, when a tiny yellow ant species showed up in my Florida backyard, I did not look into it much further. I thought it was the commonly found Wasmannia auropunctata (the little fire ant), because of its size and color, and, after all, I am more of a of termite guy. But my spouse eventually shared with me her annoyance when they started showing up in the kitchen, in shockingly large numbers. After a quick ID session, it was revealed to me that it was a new ant record in the continental U.S.: Plagiolepis alluaudi, the Alluaud’s little yellow ant. It is native to Madagascar but has spread in various places around the tropics.

Less than 2 millimeters in length, extremely polygynous and presumably exhibiting unicoloniality, it rapidly became dominant in the neighborhood. This newly found invader spiked my curiosity about invasive ants in general. After all, with about 250 species of ants in Florida, approximately one-fifth of them are invasive species, and Plagiolepis alluaudi was now added to the list. I started looking into what else was around in the yard and I found common tramp ant species that already had reached the status of global invaders: Paratrechina longicornis, Pheidole megacephala, Pheidole navigans, Brachymyrmex obscurior, Camponotus sexguttatus, Monomorium floricola, Tapinoma melanocephalum, Technomyrmex difficilis … I came to the sad conclusion that all the ant species in my urban backyard were invasive tramp species.

A Challenging Subject

Group of Plagiolepis alluaudi feeding

A group of Plagiolepis alluaudi feeding on mealybugs’ honeydew. Note on the top left corner how foragers share the droplet of honeydew. (Photo by Thomas Chouvenc, Ph.D.)

Most of these ant species have been well documented because of their long history of invasion, their wide distribution in the Southeastern U.S., and their potential economic and ecological impact. In comparison, this newly found little yellow ant has only been identified in a few localities within Broward Co. (Florida), and the literature on Plagiolepis alluaudi is mostly non-existent, except for the documentation of its wide distribution across the tropics. More problematic: its size. It is difficult to manipulate, contain, and experiment with: ask my graduate student who inherited the project to document the biology of this species. Everything about this ant species make it challenging to study.

One of the many frustrations with this tiny ant species, beyond its annoying presence in my kitchen and its difficulty to study, was my inability to properly document it with quality visuals. I invested in photographic equipment over the past two years hoping to improve my ability to show the world what this small ant was, and I attempted to document it on a dedicated Twitter account (@ant_yellow). But this side project was rapidly placed on the back burner and neglected, as I had to rethink my priorities while in a tenure track position: termites first. At the same time, like many others, I have been drooling over Alex Wild’s pictures of ants, coming to the realization I would never reach such photographic skills.

Quarantine Opportunities

Then the COVID-19 pandemic hit us. I was mandated to work from home, with a 4-year-old child. Not-going-to-happen. I believe I speak for many of us out there: academic productivity will be minimal while full-time parenting young kids. I therefore took some of Gwen Pearson’s advice and started using the backyard as more than just a playground: this is a place of wonders and miraculous bugs. My daughter tagged along with me to look at ants, mealybugs, ladybugs, planthoppers, mole crickets, butterflies … the list is actually quite long. However, this also gave me some time to (finally) look closer at Plagiolepis alluaudi. In the evening, I spent time on YouTube for advice on how to shoot bugs in macro, what options on my gear I needed to use, light requirements, for TINY LITTLE INSECTS that move fast.

Plagiolepis alluaudi forager on hibiscus flower

A Plagiolepis alluaudi forager inspecting the tip of a hibiscus flower bud. (Photo by Thomas Chouvenc, Ph.D.)

I realized that shooting at 24 frames per second (fps) in macro for this small ant would not work. They were too fast in the field of focus. I had to get closer, use tubes on my macrolens to get some focus at this magnification so they would not be the size of a pixel, and also had to switch to 180 fps. This meant: I needed a lot of light. I just happen to live in very sunny Florida, so it meant I had to learn to take videos using sunlight while avoiding the shadow of my own camera. Not easy when you are less than 2 centimeters away from your subject, and I had to learn the hard way.

Then, I spent some time learning basics of movie editing, and asked a couple of musician friends to help with the soundtrack. I was eventually able to put together an educational video aimed at the South Florida community to raise awareness about this new invasive ant. But in all reality, I just wanted to show this ant to the rest of the world. I came around to actually appreciate it.

Plagiolepis alluaudi with U.S. penny for scale

Plagiolepis alluaudi infestation in the author’s bathroom, feeding on a sweet bait. U.S. penny for scale. Yes, it’s small. (Photo by Thomas Chouvenc, Ph.D.)

I probably would never have had the time to learn the basics of macrophotography (Bugshot Florida 2020 just got cancelled, sadly) if I had not been forced to stay at home with a young child. I still have so much more to learn and improve my skills, but at least I finally got started working on them. These dramatic times are not easy for anyone, but I am fortunate to have a backyard full of wonders to explore every day, which makes the quarantine easier on us all. With this opportunity, I was finally able to take the time to look closer at this new invasive ant species.

Thomas Chouvenc, Ph.D. is an assistant professor at the University of Florida, Institute of Food and Agricultural Sciences, Ft. Lauderdale Research and Education Center, Florida. He studies termite biology, evolution, ecology, symbiosis, and control. Twitter: @ChouvencL. Email: tomchouv@ufl.edu.

4 Comments »

  1. They won’t have any effect of Florida, Florida has so many invasive ants, its not new at all, and it wont change anything.

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