Scorpions in the family Chaerilidae do not fluorescence under UV light

Scorpions fluorescence when they are exposed to ultraviolet light (in the range 320 - 400 nm). Several authors have discussed possible functions for this phenomena or if it has no function at all (previous blog posts on fluorescence).

Wilson Lourenco now reports that species in the family Chaerilidae do not fluorescence when exposed to UV light (Nine species were tested). This surprise finding is very interesting in the quest for any function of the fluorescence in scorpions. Interestingly, professor Lourenco also tested four species in the enigmatic family Pseudochactidae and they all did fluorescence. Pseudochactidae is considered to be the oldest and most primitive scorpion family and the presence of fluorescence may indicate that this is an early adaption in scorpions.

Abstract:
The fluorescence of scorpions in ultraviolet light, a well-known phenomenon, was discovered more than 60 years ago. Its possible function remains, however, a matter of discussion. Even during very recent studies, no conclusion has been reached. As suggested in these recent publications, the lack of or reduction of fluorescence could be a useful tool to explain the phenomenon. It is suggested here that, in at least some species of the family Chaerilidae Simon, this phenomenon is absent. This new discovery may initiate important comparative eco-physiological studies.

Reference:
Lourenço WR. Fluorescence in scorpions under UV light; can haerilids be a possible exception? Comptes Rendus - Biologies. 2012;335:731-4. [Subscritpion required for full text]

Thanks to professor Wilson Lourenco for sending me his paper!