Glow Up! New discovery of fluorescing lesser horseshoe bats (Rhinolophus hipposideros)

A European team of bat researchers led by Henry Schofield (VWT's former Head of Conservation) and including biologists from Pell Frischmann and the Croatian Biospeleological Society, discovered this bizarre phenomenon last year and realised the differences between species under UV light could be used as a new survey tool. The team worked with VWT, checking bat colonies in VWT roosts in Britain to see whether the fluorescing bats occurred elsewhere in Europe... they do!

The fluorescence in these two species was only observed in adult bats of both sexes and not in juveniles (at least until they were six months old). It is unlikely that this phenomenon has any function in the ecology or behaviour of the species, as horseshoe bats lack the eye structure that would enable them to detect light emitted at these wavelengths. It may also be a negative feature since some nocturnal predators may have the ability to detect the fluorescence. But for bat conservationists, the UV fluorescence demonstrated by the adults of these bats may also provide those monitoring their population status with an additional tool, especially concerning confirming maternity colonies and estimates of the productivity of colonies. 

In the case of R. blasii, it may also aid in the identification of this generally hard to spot species that often roosts with other medium-sized horseshoe bats. R. blasii is a cryptic species that roosts with R. euryale in some areas of Europe and the two species are difficult to separate without catching and handling the bats. The use of UV-torches to determine whether R. blasii is present and if so, what proportion of the mixed colony they comprise would be a non-invasive means of monitoring this species.

For more information, read the recently published paper.