Here are some recent clips of railroad-worm bioluminescence that I put together and annotated into a short film.  The brightness of the beetle’s glow and its control that it seems to have in switching on/off it’s lamps is remarkable.  The beetle is Stenophrixothrix fuscus (family Phengodidae), commonly known as the “railroad-worm” because it appears as a tiny railroad train driving through the night with its windows illuminated from within.  (This particular individual is an adult larviform female. It will never metamorphose into the typical-appearing beetle with wings, elytra and feathery plumose antennae that the adult male has.  It’s also absolutely bizarre to see them mate!)  This species emits a green light at a wavelength of about 550 nm from 8 pairs of tail lamps and a headlamp.  The lamps (aka. photic organs) are located on the last 8 abdominal segments and inside the head capsule.  One morning while sitting in a dark room, I observed an individual’s luminescence and the behavior of the light while gently blowing puffs of air to disturb it.  I found that that the headlamp remains continuously lit, while the 16 posterior tail lamps (8 pairs) turn on and off when disturbed.  In the short time that I watched, the beetle switched on all 8 segments or just one.  Photobiologists, Halverson, Case, Buck and Tiemann (1973) studied the luminescence of Stenophrixothrix, and other relatives in the luminescent beetle family Phengodidae, and found that the emitted light is neurally controlled by an adrenaline-based system. Here’s the link to the movie: https://apheloria.org/xfer/blog/Stenophrixothrix.mov

More reading about bioluminescent beetles in the family Phengodidae:

1. Halverson RC, JF Case, J Buck, D Tiemann (1973) Control of luminescence in phengodid beetles. J. Insect Physiol, 19: 1327-1339.
   

2. Arnoldi FGC, AJ da Silva Neto, VR Viviani (2010) Molecular insights on the evolution of the lateral and head lantern luciferases and bioluminescence colors in Mastinocerini railroad-worms (Coleoptera: Phengodidae). Photochem. Photobiol. Sci, 9: 87-92.
   

3. Sivinski J (1981) The nature and possible functions of luminescence in Coleoptera larvae. Coleop. Soc, 35: 167-179.
   

4. Tiemann DL (1967) Observations on the natural history of the western banded glowworm Zarhipis integripennis (Le Conte) (Coleoptera: Phengodidae). Proc. Cal. Acad. Sci, 35: 235-264.
   

5. * some really great photos in this, including bioluminescent images and Z. integripennis mating
   

6. Bioluminescent beetle, apheloria.org
   

7. Railroad-worm with a bright idea, apheloria.org