SF Peninsula Arachnids - symbiote
Scorpion, probably Paruroctonus sylvestrii, seen on the trail in the grasslands of Russian Ridge OSP on a night hike.  Illumination is a UV LED flashlight centered at 365 nm.  There's a Schott UG.1 400 nm low-pass filter in front of the light to cut out the LED's spillover into the visible, which gives a violet/blue background to most such photos.

Scorpion, probably Paruroctonus sylvestrii, seen on the trail in the grasslands of Russian Ridge OSP on a night hike. Illumination is a UV LED flashlight centered at 365 nm. There's a Schott UG.1 400 nm low-pass filter in front of the light to cut out the LED's spillover into the visible, which gives a violet/blue background to most such photos.

arachnidscorpionblacklightfluorescence