Scientists have created the world’s first genetically engineered wax moths, according to a study published in the journal Nature Lab Animal. The authors suggest that these animals could speed medical research and significantly reduce the use of mice and rats in research.
For their work, researchers from the University of Exeter, UK, used the greater wax moth (Galleria mellonella), a small insect that is increasingly seen as an ethical and practical alternative to mammals in infection research.
The need for faster, better testing is urgent. Antimicrobial resistance (AMR) is considered one of the most serious threats to global health. Dr James Pearce from the University of Exeter said: “With AMR posing one of the biggest threats to human health, we urgently need faster, ethical, and scalable ways to test new research. Engineered wax moths offer exactly that; a practical alternative that reduces mammalian use and accelerates knowledge discovery.”
What makes the greater wax moth particularly useful is that it can be kept at 37 degrees Celsius and its cells respond to bacterial and fungal infections in a way that closely mirrors what happens in mammals. This makes it a far more relevant stand-in than most other non-rodent alternatives. Until now, however, its potential has been held back by the absence of the genetic tools needed to study and modify it.
The Exeter team overcame this by adapting techniques originally developed for fruit fly research, using them to create wax moth lines that are either fluorescent or gene-edited for the first time. This opens the door to so-called “sensor moths”: larvae that glow when they become infected or respond to antibiotics, providing a living, real-time view of how disease and treatment interact inside a whole organism.
“By putting new genes into the wax moth genome, we’re able to make larvae that glow in a controlled way. This paves the way for ‘sensor moths’ that light up when infected or responding to antibiotics – offering a living, real-time window into disease,” said Professor James Wakefield from the University of Exeter.
The moths can be infected with human pathogens including the superbug Staphylococcus aureus and the fungus Candida albicans, making them a realistic testing ground that sits between basic laboratory cell cultures and full animal trials. “Our methods make wax moths genetically tractable for the first time. The ability to insert, delete or modify genes opens huge potential, from understanding innate immunity to developing real-time biosensors for infection,” added Dr Pearce.
The potential impact on animal testing is significant. Around 100,000 mice are used each year in the UK for infection biology research alone. If just 10% of those studies switched to using moths instead, more than 10,000 mice a year could be spared — while still producing scientifically robust, human-relevant results.
Pearce, J.C., Campbell, J.S., Prior, J.L. et al. PiggyBac-mediated transgenesis and CRISPR–Cas9 knockout in the greater wax moth, Galleria mellonella. Lab Anim 55, 95–102 (2026). https://doi.org/10.1038/s41684-025-01665-7