Figure 2

Fully developed self-sustained antenna oscillations (SO) of Drosophila, 20 min after DMSO injection (after Ref. 30).

(a) Red: Data from³⁰, green: simulations. (b) Best data-based polynomial approximating ordinary differential equation of SO , with polynomials of order n = 2 and m = 5, respectively. At extracted parameters, this system is close to a Hopf bifurcation, cf. Fig. 3. The damping term Pn(x) shows negative damping around the origin (Pn(x) < 0); the restoring force Pm(x) shows areas of negative stiffness Pm′(x) < 0. (c) Red: Data from³⁰, green: low-passed reconstructed SO data.