Scorpions are ancient arachnids known for their distinctive appearance and venomous sting. One intriguing characteristic is their ability to emit a striking glow. This unique trait makes these nocturnal creatures visible under specific lighting conditions.
Understanding Scorpion Fluorescence
The glow in scorpions is fluorescence, which is distinct from bioluminescence. Bioluminescence involves an organism generating its own light through chemical reactions, as seen in fireflies. Scorpion fluorescence, however, occurs when their exoskeleton absorbs invisible ultraviolet (UV) light and then re-emits it as visible blue-green light.
This reaction takes place in a tough outer layer of their exoskeleton called the hyaline layer. Scientists have identified specific compounds within this layer, such as beta-carboline and 7-hydroxy-4-methylcoumarin, that are responsible for absorbing the UV light. The glow is a physical property of these compounds, not a result of a living biological process within the scorpion.
The Universality of the Glow
Most scorpion species fluoresce under ultraviolet light. However, there are nuances and conditions under which this glow might be absent or less pronounced. One common exception is newly molted scorpions. Their fresh exoskeletons have not yet fully hardened or developed the necessary fluorescent compounds, so they will not glow immediately.
The fluorescent compounds are thought to be a byproduct of the hardening process or secreted shortly after molting. Young scorpions (scorplings) may not glow strongly because their exoskeletons are still developing these proteins. The glowing property is remarkably durable. Dead or preserved scorpions can still fluoresce, and even scorpion fossils dating back millions of years retain this ability, highlighting the resilience of the hyaline layer.
How to Observe Scorpions Glowing
Observing scorpions glow requires a UV light, commonly known as a “black light.” These lights typically emit wavelengths in the 365-395 nanometer range, which is ideal for triggering the scorpion’s fluorescence. For best viewing, conduct observations in dim or dark conditions, as ambient light can diminish the glow’s visibility.
When searching for scorpions with a UV light, safety is important. Direct exposure to strong UV light can harm eyes, so UV-blocking safety glasses are advisable, especially with powerful devices. Additionally, wearing protective clothing such as gloves, boots, and long pants is recommended to prevent accidental stings when exploring areas where scorpions might be present. This method is widely used by researchers and pest control professionals to locate scorpions in their natural habitats.