During the fall and spring, Blue Thumb volunteers join us for macroinvertebrate subsampling, or what we like to call “bug picking.” At these events, volunteers meet with us at an indoor location, where we bring the bug sample that they helped us collect from their stream the previous winter or summer. We divide the sample into a small fraction of what’s in a mason jar and put it into a tray separated into numbered squares. Then, the volunteers use a magnifying lamp and tweezers to pick through the bugs in each randomly selected square, at least five squares, until they find at least 100 bugs. Blue Thumb staff then put the bugs into a vial to be sent off to a taxonomist for further identification. Many volunteers have asked about that process, who identifies the bugs, what they look for and how or why the identification takes place. While we have been sending bugs to a taxonomist in Texas, our colleague here at the Conservation Commission has been working hard to become our in-house bug identifier. Here's his story:
Hello, I’m Nathan Carter and I live in rural Northeastern Oklahoma with my wife and our three daughters who luckily, are accepting of my various quirks that allow me to be what I am! Actually, my home is not far from where I spent my childhood and the stream that ignited my curiosity about the creatures that live in our streams. One of my favorite activities as a child was to go to the creek on my family’s property and flip rocks to see what I could find hiding underneath them. As I grew older, my interest led me to finding deep holes in the creek and fishing with rod and reel and eventually I even started seining the creek with whomever I could get to help me. I was always fascinated by the variety of bugs and fish that I could find! I could recognize a few of them but many of the creatures I found I could only describe by their appearance or how they acted when I captured them. Just like the majority of rural children, I maintained that close tie to the outdoors into adulthood and that tie influenced me greatly when I considered what I should do after high school. I began a meandering journey toward higher education that eventually led me to Northeastern State University. The majority of my time at NSU was spent studying the life that could be found in the many Ozark streams that surrounded the campus, those streams are where I really honed in on what I wanted to do after college. My introduction to the Oklahoma Conservation Commission (OCC) was purely by chance. I didn’t keep in close contact with my advisor so it was odd that I happened to bump into her and she let me know about an internship advertisement for the OCC. I interviewed and was selected to be an intern during the summer of 2010. My experience was such that I could not see myself doing anything else. I returned for the summer of 2011 and was hired as a full time employee in the fall of 2011.
Since I’ve been with the OCC, I have received many opportunities to expand my knowledge and competency beyond just carrying backpack shockers and keeping up with paper work. While there is still plenty of both of those, I am now a crew leader for summer fish collections and habitat assessments, I act as our fish taxonomist and I identify all of the fish samples that our crews and Blue Thumb collect every year. I can measure high flow discharge with the OCC’s ADCP, I get opportunities to help educate groups of professionals and students about fish identification, and now I am a certified benthic macroinvertebrate taxonomist with the Society for Freshwater Science. My work with the macroinvertebrates has been my most interesting venture yet. It began with subsampling many hundreds of bug samples that are collected in the summer and winter. Over time, I became familiar with the organisms that I was removing from the sample to be sent off for identification but I wanted to know more. After researching what it would take to become a taxonomist myself, I learned about the Society for Freshwater Science and their certification program. I was fortunate in that there were endless supplies of preserved bugs for me to practice with, so I found the recommended text and began keying out bugs one by one. Once I had familiarized myself with my collection, I set about becoming certified and I have now passed two ID tests. This process took me well over a year before I felt that I had even the most basic knowledge and continues now even after being certified.
When I begin identifying a bug sample, I remove the bugs from the vial that they are stored in and place them in a petri dish so I can look at them under my microscope. Next, I start looking at each individual bug, one by one. At this point, I know many of them just by sight but at first I had to use a key to key each of the bugs, a process that would take hours. The ID process is made much more difficult if the bugs are damaged at all because in order to correctly identify them you need to look at minute details like the shape of their gills or even the tiny hairs on the bug’s mouth parts! It is necessary to look at them at that level of detail because of the great diversity among benthic macroinvertebrates, with Oklahoma having hundreds of genera and many thousands of species. It is that diversity that makes them so interesting to me.
The bugs that we find can tell us about a stream’s water quality. Simply put, bugs can be divided into two groups, those that are intolerant to pollution and those that are tolerant of pollution. Any time the majority of the bugs in a sample fall in the tolerant group, it is an indication that there is something bad occurring in that stream. That is an extreme simplification but is the general premise for our analysis. Bugs that I hope to find and that are universally recognized as good indicators are members of EPT group. EPT is made up of the families Ephemeroptera, Plecoptera, and Trichoptera, more commonly known as mayflies, stoneflies, and caddisflies. These bugs are all generally intolerant to pollution and are used as indicators of water quality. Conversely, many true flies, dragonflies, and leeches are tolerant to pollution to varying degrees. Just because a sample contains bugs that are tolerant to pollution, does not necessarily mean that the stream is polluted as long as there are plenty of members of the intolerant group as well. However, if the sample is made entirely of tolerant bugs or worse, there are no bugs found, then there is a definite pollution problem in the stream.
My work with identifying bugs feeds my curiosity. I love the diversity of the organisms and I relish the instance where I find a bug that I have yet to see in person or when I come across one that is very rare. Surprises are not uncommon and it is a treat when I find a bug that I think could never have come from a particular stream because on the surface that stream appeared to be far too polluted and yet they are there. I enjoy finding hidden gems like that across the state and for me it is a sign that our work at the OCC can pay off when streams improve to the point that these very interesting bugs can live there once again.