IRMS (Isotope Ratio Mass Spectrometer) "isotope study"

IRMS (Isotope Ratio Mass Spectrometer) isotope investigations

After more than 30 years of researching the sources that up until now have been available to me in order for me to find a solution to the question as to where these butterflies have been collected, the problem seemed insoluble. So one afternoon as I quickly looked through a newly published issue of the Swedish “Entomologisk Tidskrift” (Entomological Journal) I saw a call for help where Oskar Brattström talks about the work of using isotope studies, IRMS (Isotope Ratio Mass Spectrometer) of captured migrating butterflies like the Painted Lady and the Red Admiral, Vanessa (Cynthia) cardui and Vanessa atalanta to try to determine whether these migrants, in Sweden, come from Spain and North Africa or if they had flown to Sweden from south-eastern Europe or the Caucasus. Of course, my thoughts went directly to the question of Colias ponteni’s descent. Perhaps one can get a clue about whether the butterflies are caught at the Strait of Magellan's or in the Hawaii archipelago using isotope investigations? The straight line distance between these places is almost 12000 km so it should be possible to see a significant difference. The bedrock is also quite different, although some volcanic activity also occurred at the Strait of Magellan, albeit of a completely different intensity than the Hawaiian Islands.

Oskar Brattström liked the idea and promised to investigate whether there was any possibility of doing these investigations. A major problem with this type of examination is that certain material must be taken from the butterfly itself. It was of course impossible to take any part of the syntypes at the Natural History Museum in Stockholm. After conversing with my friends at the Museum of Evolution, where I suggested the possibility that we might through this method be able to solve the question of the origin of this completely unique species, I was allowed to take an extremely small piece of the front edge of the hindwing which in both living and in normal set positions is under the inner margin of the forewing.

It then remained to find suitable comparative material, both from Hawaii and also from the Strait of Magellan. When it came to the Strait of Magellan, this was no problem as my Japanese friend and tireless collector Hiroshi Hara, sent me several specimens of Colias vauthierii cunninghamii which he had captured at the Strait of Magellan. When it came to Hawaii, of course, there are no Colias

butterflies to compare with, so I had to take some other butterflies from my own world collection that came from the Hawaiian Islands. It had to be a Monarch butterfly, Danaus plexippus and a Long Tailed Blue, Lampides boeticus, both butterflies collected on the island of Oahu. The latter kindly donated to me for this purpose by Jack Harry in USA

After a long time at the laboratory in Canada we got the results from their isotope studies. These show a notable similarity between Ponten's and/or Kinberg's collected Colias butterflies and my butterflies collected in Hawaii while the difference between Pontén's and/or Kinberg's collected Colias butterflies and the Colias butterflies, Colias vauthierii cunninghamii, which Hiroshi Hara collected at Strait of Magellan is clear. The comparative figures with the butterflies from the Strait of Magellan show on average "-101" while for the butterflies that have been collected on the Hawaiian Islands lies on average "-65" and the samples we have taken on two of the Colias ponteni butterflies are on average "-74". I would also like to take this opportunity to thank Nicklas Wahlberg who now works as the Zoologist in Lund for his help in reconnecting with Oskar.

Both Oskar Brattström and I are, of course, aware that this isotope survey is not a comprehensive proof that the butterflies Pontén or Kinberg presented to Wallengren are really collected by those gentlemen on Oahu, which they have always declared. Along with previous discussion in this article, Hawaii rather than Port Famine on the Strait of Magellan, appears a much more likely place where this butterfly was collected. Oskar Brattström has long intended to publish this and his other isotope studies for more than 9 years, since the spring of 2010. I have been waiting to publish this long article about my soon 50-year study of the butterfly Colias ponteni, but when the newly started DNA study came to my knowledge a month ago, I felt that even though vague promises to Oskar about the opposite, I still want to publish my article that was mainly written so long ago for publication in our journal at the same time as Oskar publishes his article on his isotope studies. However, that now completely omits Oskar's company isotope survey, which was de facto initiated by me, which feels completely wrong which is why I made the decision to mention this isotope investigation, which in any case strongly points to Hawaii as the right place for Colias ponteni. During the course of publishing this article over the summer, I have also received permission from Oskar to publish the above related results of the isotope study, which of course I am very happy about.