Overview
- Male Doratosepion andreanum extend and coil specialized long arms during courtship to create alternating bands of horizontally and vertically oriented light that are highly conspicuous to cuttlefish vision.
- In observation tanks that replicated oceanic horizontal polarization, polarization‑camera footage showed no such pattern in non‑courting states, indicating the signal is specific to courtship.
- Optical tests and tissue analyses found iridophores generate horizontally polarized reflections that rotate by roughly 90 degrees to vertical as light passes through transparent, birefringent arm muscle.
- The arm shape and thickness enhance the effect, with adjacent arm tips producing especially strong polarization contrast comparable in conspicuousness to colorful ornaments in other species.
- The authors present this as the first evidence of a mating display based on polarization patterns invisible to humans, and an outside expert suggested possible bio‑inspired and underwater signaling applications that remain speculative.