Entomoscope: An Open-Source Photomicroscope for Biodiversity Discovery

Abstract

Understanding and slowing down biodiversity loss are critical tasks for the survival of our planet. They are difficult because much of the earth's biodiversity is concentrated in abundant and species-rich groups of invertebrates like insects. Traditionally, bulk samples of insects had to be analyzed manually by experts using morphology. Not only did this require much taxonomic expertise, but it was also error-prone, time-consuming, and almost always involved commercially available microscopes that are too expensive for many biodiverse, tropical countries with limited science funding. An alternative to sorting bulk samples by experts using morphology is the use of DNA barcoding. However, this requires a well-equipped molecular laboratory and a different skill set. We present an alternative solution - the Entomoscope, a low-cost, open-source photomicroscope for taking high-resolution, focus-stacked images that can be used for insect classification. We describe two different versions of the Entomoscope, a standalone version that can be operated without additional hardware and an even simpler version, that is operated via a computer. We show that the optics are of sufficiently high quality to classify specimens with >95% accuracy into 15 different types of insects (mostly 'families' according to the Linnaean classification). The classifier can be successively extended or individually trained for specific classification tasks. We provide the building instructions, 3D files, and a list of commercially available parts so that everyone can build their own Entomoscope. We predict that open-source DIY hardware like the Entomoscope will facilitate cutting-edge biodiversity research by entomologists around the planet.