On four gloriously sunny days in June, a small team of entomologists convened at Kenai National Wildlife Refuge to do what entomologists do best: collect insects.
They had come to take part in a rapid ecological assessment of arthropod biodiversity in which as many species as possible are collected in a short time. The goals were twofold: to augment the list of arthropods known to live on the refuge and to build a corresponding library of DNA barcodes for those species. The project blends old–fashioned collecting in the spirit of 19th–century explorers with modern DNA work.
The whole idea is to work myself out a job.
Though the ecological importance of insects is plainly evident and their quick responsiveness to environmental change makes them ideal candidates as indicators of habitat quality, the trouble with insects is that they are hard
to identify.
It took years to sort through more than 15,000 specimens collected from 2004 to 2006 as part of the refuge’s Long Term Ecological Monitoring Program, and many remain unidentified today. If insect diversity is to be monitored feasibly, this identification problem must be surmounted.
Our plan at Kenai Refuge is to take bulk samples of hundreds of insects, liquefy them in a blender, extract the insects’ DNA from the slurry, and—using a next–generation DNA barcoding method—obtain a list of species present in the sample.
DNA barcoding is the use of a short section of DNA for species identification, not unlike recognizing products in a store by their barcode labels. This method will make monitoring of insects much more manageable by eliminating the tedious task of sorting and identifying them using forceps, microscope and identification keys.
However, this next–generation method requires that a library of DNA barcodes from known specimens be established first. Otherwise, barcodes obtained from a slurry of pulverized insects are nothing more than barcodes. We began building this library last winter by sequencing specimens already in Kenai Refuge’s entomology collection, but the collection included only 208 species, just a small portion of the refuge’s arthropod diversity. In June, we sought to build on the collection.
All–Star Team
With help from an all–star team of four Alaska entomologists, we scoured the refuge, visiting as many habitats as possible in four days. We surveyed the forest, muskeg and lakeshore near refuge headquarters. We toured habitats along Skilak Lake’s shore. At Emerald Lake, we sampled the subalpine thickets, meadows, waters and alpine habitats.
We employed various collecting methods (sweep nets, beat sheets, aerial nets, malaise traps, pan traps, sieves, aquatic nets, streamside washing) and searched by hand under stones, logs and bark. Each of us focused on the methods and insect groups we knew best.
I have since begun cataloging the many vials, bags and containers of insects we obtained. I don’t yet have a reliable estimate of the number of specimens and species we collected. I can say it was at least thousands of specimens, representing probably hundreds of species. Incidentally, we found a northern holly fern near Emerald Lake, a plant species not previously recorded at Kenai Refuge.
The insect specimens will be sorted and mailed to specialists for identification. This winter, the specimens will be sent for DNA barcoding. Specimen data from this project is being posted on the Internet in near–real time via the Arctos database (http://arctos.database.museum/knwr_ento).
As we obtain DNA barcodes, they will be deposited in the National Center for Biotechnology Information’s GenBank, where they will be useful not only to Kenai Refuge but also to any study using DNA barcodes to identify insects. Our efforts will allow national parks, national forests and other refuges to rapidly assess insect diversity on their respective pieces of Alaska.
Matt Bowser is an entomologist at Kenai National Wildlife Refuge. This article originally appeared in the Peninsula Clarion newspaper on
Aug. 5, 2011.
