Marzipan and Iodine: Sniffing out bioluminescence
Deep in Sequoia National Forest, just after the winter snow melts, in groves, meadows and grassy clearings, the stars of the night sky are reflected in the vegetation below. The source of this most natural light are hundreds of bioluminescent millipedes of the genus Motyxia. Only found in certain parts of the National Forest and at specific altitudes, these millipedes are among few animals of their type to produce light. If this is sounding familiar, it’s because I tried to photograph them last year, but mostly failed. You can read about that episode here.
Fast forward ten months and my wife Julie and I were making our way back along a hiking trail in Sequoia National Forest, in the dark. We came across a small clearing where we found tens of these special bugs glowing at our feet, and without the help of any artificial light sources. With our lights off, and once our eyes had properly adjusted to the darkness we saw them dotted all over the clearing, slowly going about their business, their entire bodies and many appendages glowing with a beautiful aqua-blue bioluminescence. Where we had seen few during daylight hours, there were now many, as they slowly meandered across the forest floor we took a moment to take in a scene that looked like something from a Studio Ghibli movie.
When all was said and done, we were extremely tired after working through the night, but mostly grateful to have experienced something so beautiful and to have had the chance to share it here. We also learned something too, and that is to do with the way these millipedes smell. The non-bioluminescent types we saw generally gave off an aroma of iodine or antiseptic, while the slightly larger, bioluminescent species smelled more like marzipan or almonds. While interesting, it is advised that you don’t spend too long sniffing millipedes as both smells are indicative of cyanide. Professor Paul Marek has evidence that suggests that the bioluminescence of Motyxia could be a type of aposematism, warning would-be predators to the toxic compounds secreted within. UPDATE: After the rediscovery of a new bioluminescent species in San Luis Obisbo County, CA, it is thought that bioluminescence in these millipedes may first have been an evolutionary by-product as the millipedes adapted to living in a hot, dry climate. The fact that bioluminescence helps deter predators from eating these bugs ended up being a fortunate, added benefit. Read the paper by Marek and Moore here, and read a National Geographic web article here.
Of all the bioluminescence I have ever seen, it certainly wasn’t the brightest, which made photographing them very difficult. I was generally working with an exposure of around 13 seconds at maximum sensitivity and widest aperture, so getting a sharp image of these things as they moved was a rare occurrence. Photographing or filming bioluminescence is among the most difficult subjects I have ever tried to capture, and in fact, I used to work for Martin Dohrn who has spent most of his life actually building video cameras to do the job. I experimented with very low levels of flash to give detail to the animals’ bodies and context to the place they lived, but this generally lessened the impact of the bioluminescence, I instead opted for the ‘glowing creature in the dark’ look.