On our FaceBook page and on this CBC website we are used to recording any Bath White as the Eastern Bath White - Pontia edusa. This is a bit of an assumption because there are in fact two species of Bath White found in Europe.
In the west of the continent we find the Bath White - Pontia daplidice and as you have probably guessed, in the east we find the Eastern Bath White - Pontia edusa. The two species meet somewhere in the north of Italy, where some say there is hybridisation between them. Scientists tell us that the two species are morphologically identical (they look the same) but are biochemically distinct (they have different genes and so are separate species). So on the face of it one might consider that we are fairly safe in concluding that the species we find on Corfu is the Eastern Bath White - P. edusa.
However, the Bath White - P. daplidice has also been found in Cyprus and so we must consider the possibility that this species may have also spread north to Corfu (both species are known to share their distributions in some parts of Turkey). Until we receive permission to undertake genetic barcoding of the butterflies on Corfu we are left with the unenviable task of looking for differences in wing patterning where others have failed to find such differences.
Fortunately, there has been some success with this approach in other parts of Europe and so at this time of year, when the Bath White can be found on Corfu in high abundance, CBC is asking you to take as many closed wing shots of this species as you can and then post them on our facebook page. Such images will help us see if there is any morphological evidence for either or both species on the island, which we will compare with the results of genetic analysis, once permission to do so has been granted.
Here are some examples of the types of photos we hope to see posted and some that are of lesser value - please see the comments attached to each image.
When we have looked at enough images we will get back to you with our results.