# In-vivo biomagnetic characterisation of the American cockroach

## TL;DR

This study introduces a novel quantum sensor-based method for non-invasively characterizing magnetic properties inside living insects, revealing differences in magnetic deposits between alive and dead American cockroaches, and advancing understanding of insect magneto-reception.

## Contribution

It is the first to characterize magnetisation dynamics in live insects using quantum sensors, linking behavioral and material magnetic properties.

## Key findings

- Magnetic deposits differ between live and dead cockroaches.
- The method enables non-invasive, in vivo magnetic characterization.
- Insights into cockroach magneto-reception mechanisms.

## Abstract

We present a quantitative method, utilising a highly sensitive quantum sensor, that extends applicability of magnetorelaxometry to biological samples at physiological temperature. The observed magnetic fields allow for non-invasive determination of physical properties of magnetic materials and their surrounding environment inside the specimen. The method is applied to American cockroaches and reveals magnetic deposits with strikingly different behaviour in alive and dead insects. We discuss consequences of this finding to cockroach magneto-reception. To our knowledge, this work represents the first characterisation of the magnetisation dynamics in live insects and helps to connect results from behavioural experiments on insects in magnetic fields with characterisation of magnetic materials in their corpses.