INSTAR: reporting items for invertebrate welfare in research

Thomas Edward White , Kate Lynch, Jonathan Amory, Caitlyn Forster, Adam G Hart, Tanya Latty, Kate Umbers, Eleanor Drinkwater

Concern for the welfare of research animals has expanded rapidly across taxa, with increasing focus on invertebrates. Recent evidence for affective experience in cephalopod, decapod and insect taxa, alongside shifts in public attitudes and regulation, has raised the stakes of how invertebrates are used and reported, yet no reporting standard adequately addresses them. Here we present INSTAR (INvertebrate Standards for Treatment And Reporting) v1.0, an 18-item reporting standard. It does not assess or score welfare; it asks authors to report all facets of the handling and treatment of invertebrates in research and the reasoning behind it, spanning three cross-cutting foundations (Subjects, Procedures, Ethics and Compliance) and five welfare domains adapted from the Five Domains Model (Nutrition, Environment, Health, Behaviour, Affective state). It suits laboratory and field contexts alike, and is supported by a free R package and web tool. To establish current practice we surveyed 150 recent papers across 15 journals, scoring 2,700 item-level judgements, and found median coverage of 62.5% of applicable items. Welfare-specific items were rarely reported: humane endpoints in 10% of papers, welfare and three-Rs statements in 17%, and affective-state indicators in 32%. INSTAR is minimally burdensome, its primary output being a reporting sheet deposited alongside the paper, no more work than the methods paragraph itself. Wider adoption would make the treatment of invertebrates visible and comparable across studies, let reviewers and ethics bodies ask for what is missing, and establish a baseline against which improvement can be measured for the majority of animals used in research.