Succumbing to the lure of the model organism: studying the imported red fire ant

Guest Post by Karl Roeder

Ants. The adorable arthropods that have captured my imagination for years have finally become the focus of my Ph.D. research. They are abundant, diverse, and ecologically important with a variety of castes that contain a range of alternative phenotypes that differ in body size, life span, societal role, and reproductive output. Quite simply, ants are awesome. But perhaps most importantly for my work, they occupy almost every trophic level in a community.

So what am I up to? Besides cataloging the ant diversity across Oklahoma, I am working towards understanding the factors that influence stable isotope signatures. Specifically, I will be looking at variation in Nitrogen (N) and Carbon (C) isotopes as these are routinely used to estimate the trophic position and carbon flow of organisms. Together N and C help piece together how energy flows through a food web. However stable isotope studies using ants are presented with a variety of challenges.

The tools of the trade

Tools of the trade when studying fire ants. All this, and a strong immune system. 

One challenge is size. In this case I am not just talking about body size but also colony and potentially population size. Understanding how and at what level size influences the intraspecific variation in isotopic signatures are first steps towards using stable isotopes to definitively map the trophic structuring of ant assemblages. In my mind it is vital to determine if a species’ isotopic signature is due to its diet or an artifact of morphological or behavioral mechanisms. Either way, the answer should be interesting!

Fire ants

After extracting ants from all that soil, Solenopsis invicta shows a range of sizes. 

This summer I am based at the University of Oklahoma Biological Station to work on these questions. And as an added bonus I am working with one of my favorite species, Solenopsis invicta. Having been intimately acquainted with the red imported fire ant for almost three years, I still find myself continually fascinated by their life history. Polymorphic workers, mono- and polygyne queens, unmatched aggressiveness, painful stings, and a behavioral escape mechanism to floods by rafting (and thank goodness given the amount of rain in Oklahoma this summer!). Perhaps it seems fitting that I continue to work in this system, as they appear to be the perfect model organisms to address my surplus of size based questions. Just remember to grab your shovel!

%d bloggers like this: