WIBSRC Alexander Fleming · SpinBio
Coordination between physically separated fliesTesting a candidate electromagnetic mechanism.
Wi-Fly investigates whether Drosophila melanogaster, housed individually without visual, tactile or olfactory contact, show coordinated changes in locomotor state. The experiments test whether near-field electromagnetic coupling could contribute to the effect.
Experimental design
Forty-eight flies are recorded simultaneously in a 3D printed opaque plastic multiwell plate, with one animal in each optically and mechanically isolated well. The animals share the plate and the imposed light schedule, but have no direct visual or tactile contact.
Light transitions produce a common behavioural response across the plate. This shared stimulus can generate apparent synchrony even if the animals do not influence one another, so it must be separated from any additional coordination.
The analysis compares pairwise correlations within the same transition with correlations for the same pairs across different transitions. Both comparisons contain the stimulus response; their difference estimates coordination beyond that common drive.
Analysis framework
Three quantities derived from the locomotion traces.
- Δ
The difference between within-transition and cross-transition pair correlations after Fisher z transformation. This comparison controls for the shared response to the light transition.
- χ
Background common-mode activity, N·Var(M), estimated away from transitions. It quantifies plate-wide covariance arising from drift, vibration or other shared influences.
Statistical significance is assessed by permutation testing with max-statistic correction across analysis windows. Leave-out procedures are used to evaluate common-mode removal.
Material comparison
Testing the effect of plate conductivity
If coordination depends on near-field electromagnetic coupling, conducting plates should attenuate it relative to an insulating plate. The experiment was therefore repeated in geometrically matched PETG, steel and aluminium plates.
An insulating reference material expected to produce the least electromagnetic attenuation between wells.
A conducting material with greater measured sub-gigahertz near-field transmission than aluminium.
The most conductive material tested, with the shallowest calculated skin depth and greatest expected attenuation.
The principal comparison is PETG versus metal. The steel–aluminium difference is in the predicted direction, but the present data do not provide a well-powered test of that contrast.