Centipedes sense heat to see

When centipedes are exposed to light, they scurry back toward the dark. So scientists perusing the centipede genome after it was sequenced in 2020 were surprised by the absence of any recognizable photoreceptor proteins. Researchers investigating how the arthropods sense light have found a possible explanation. The crawly critters have temperature-sensing ion channels in their antennae and seem to be able to convert light into heat to activate the channels (Proc. Nat. Acad. Sci. U.S.A. 2023, DOI: 10.1073/pnas.2218948120).

Scientists at Northeast Forestry University led by biologist Shilong Yang found, using thermal imaging, that centipedes’ antennae heat rapidly when illuminated. The antennae get much hotter than the rest of the creatures’ bodies. When their antennae were covered with foil, the centipedes were much less likely to flee from bright light.

To find out how the organ senses the heat it generates, the researchers expressed proteins from centipede-antenna sensory neurons one by one in cultured cells and used calcium imaging to find a cation channel that opens when heated. It’s not clear how the antennae warm up so efficiently when exposed to light, though similar photothermal effects have been observed in other arthropods. But the centipedes seem to be able to sense the heating and use it to “see” changes in light levels. The researchers hope to determine the structure of the new channel, which is unrelated to known heat-sensing proteins, for more insight into how centipede heat sensing works.