The need for a (non-destructive) method revolution in entomology

There are worrying signs that arthropods are in decline both in density and diversity. This threatens global biodiversity as well as the ecosystem services provided by arthropods. Nonetheless, entomological research, even when studying arthropods with a conservation focus, frequently uses lethal methods. We analysed 1029 articles published in the major biological conservation journals between 2014 and 2020 and found that, while single-species-focused studies used more non-lethal than lethal methods (76.3 % vs. 23.7 %, respectively), the opposite was true for multiple-species ones (24.0 % vs. 76.0 %). In tropical regions, 74.6 % of studies used lethal methods vs. 18.5 % non-lethal ones. Of the major orders, Odonata, Lepidoptera and Orthoptera were generally studied using non-lethal methods (88.1 %, 80.7 %, and 70.8 %, respectively) in non-tropical regions, while in the tropics, only Lepidoptera were frequently (51.9 %) studied by such methods. We argue that even if the evidence for arthropod decline were uncertain, and even if research would not add much to the overall level of mortality, entomologists should be showing an example. If research on invertebrates continues to be ethically blind, entomologists risk losing public support for conserving arthropod diversity.