Tropical eDNA sampling and its challenges

While insect decline is a growing concern globally, relatively little is known about the rate of this decline, and even further less is known about the declination rate of aquatic insects. In light of the threats posed to global biodiversity, especially in tropical regions that hold a large percentage of the earth’s biodiversity, the importance of non-invasive sampling and monitoring techniques for these macroinvertebrate communities cannot be overemphasized. Using environmental DNA (eDNA), which incorporates DNA metabarcoding, the entire breadth of macroinvertebrate communities can be studied with minuscule quantities of DNA expelled into the aquatic matrix. However, given the dramatically different environmental conditions globally, there are inevitably variations to the efficacy of this technique in different bioclimatic regions, particularly in the tropics. These environmental factors could affect detectability and by extension, the success of this technique. Through preliminary research and some metadata, we identified some of the factors that negatively influence eDNA sampling in the tropics such as high temperatures, and the high presence of PCR inhibitors. We hope that by accounting for these factors in future efforts, the success of eDNA sampling and metabarcoding will be improved.