Development of alternatives to mammalian models in medicine

Caterpillars as a replacement for mammalian models in preclinical research

Insect larvae such as tobacco hornworm can accelerate and economize preclinical research by complementing classic laboratory animals such as rats and mice.

© Fraunhofer IME | Kim Weigand
© Fraunhofer IME | Anton Windfelder
© Fraunhofer IME | Anton Windfelder

Small mammals like mice or rats are indispensable for preclinical research. However, growing ethical concerns led to the incorporation of the 3R principle (replacement, reduction, and refinement) into animal experiments legislation and research funding. In the future, the number of vertebrate laboratory animals should be reduced, and non-vertebrate alternatives should be used where possible. Furthermore, the incorporation of the 3R principle will also economize preclinical research since insect husbandry is much cheaper than the traditional housing of laboratory mammals.

In that context, insect larvae like Manduca can serve as an alternative in vivo animal model. Particularly, with the high degree of evolutionary conservation in the innate immunity of the gut and similarities in the enteric epithelial structure, Manduca sexta can serve as a model for human gut inflammation.

In the introduced paper, we employed larvae of the tobacco hornworm Manduca sexta, which are big enough for macroscopic imaging techniques, such as computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET) as a high-throughput platform to study the innate immunity of the gut and host-pathogen interactions.

The developed platform represents an ethically acceptable, resource-saving, large-scale, and 3R-compatible screening tool for various life science disciplines, including the identification of new effectors and inhibitors in gut inflammation, the assessment of pesticides or other environmental factors, the assessment and evaluation of new antibiotic therapies, the analysis of host-pathogen interactions, and the identification of new contrast agents or tracers in radiology. Since 75% of the known human disease-causing genes have homologs in insects, this approach will also be helpful in testing preclinical hypotheses in inflammatory bowel disease.


Windfelder et al. High-throughput Screening of Caterpillars as a Platform to Study Host-microbe Interactions and Enteric Immunity. Nature Communications


Laussmann et al. Dynamic monitoring of vital functions and tissue re-organization in Saturnia pavonia (Lepidoptera, Saturniidae) during final metamorphosis by non-invasive MRI. Scientific Reports


How does the contrast agent work?


MRI scans

Heartbeat of the larvae


a-c in sagittal and d in axial orientation

Application of the contrast agent

MRI scans