Summary; My own reflections

Colias ponteni Wallengren, 1860

47 years of investigations thought and speculations over a butterfly

Göran Sjöberg, Avellaneda Museum, Gävle, Sweden ngsjoberg@gmail.com

The world's most wanted butterfly - the only butterfly we do not quite know in which part of the world it was collected!

Where was it? Does it still survive? Which locality is the most likely? What theories are there today, 167 years after the last specimens were collected? Can the riddle be solved?

These are questions that I have thought about during my spare time and searched for the answers over the last 47 years.

With improved DNA technology, there is perhaps now finally an opportunity to gain clarity to this mystery, which, for a long time employed me and a host of researchers worldwide including many of my friends since 1972. With this article I want to tell you about the background to this mystery which, since the late 1800s, has caused so many headaches. I am also aware that in this article there are some repetitions but ask your readers to overlook this as it has been written during a period of more than 30 years and I am now unable to edit the entire material before the forthcoming DNA investigations.

Syntype: male of Colias ponteni Wallengren, 1860. Naturhistoriska Riksmuseet Stockholm. Photo Göran Sjöberg.

Summary

This is an account of what I consider after 50 years of study with regard to the mysterious butterfly Colias ponteni which was described in 1860, eight years after it was said to have been found in Hawaii during midsummer of 1852. The Swedish Frigate Eugenie made a two-week long beach anchorage at Honolulu on the island of Oahu in the Hawaii Archipelago for restocking food and water and for collecting animals and plants. Since that visit the butterfly has never been found again. On the other hand, it is said that another three, two males and one female, of the same species, were found in a herbarium in the Bank's collection in 1871. The herbarium was considered to originate from the English expedition with HMS Adventure to the southernmost South America from 1826 to 1827 under the leadership of Captain Phillip Parker King. Arthur Gardiner Butler then described these butterflies as a new species in 1871, i.e. 44 years after they were possibly collected. Who collected these butterflies is unknown as well as where this collection really was made. Butler listed Port Famine, a trading and refueling station with an old penal colony on the northwest coast of the Strait of Magellan in southernmost South America as a catch site, based on some plants in this herbarium identified with Port Famine as their collection site. Live specimens of the butterfly have never been found.

Three more specimens of the species are now available at the British Museum Natural History. Two of these, one male and one female are labelled “Sandwitsch Inseln”, something that suggests that even these were collected before the frigate Eugenie's visit. Since the name Sandwich Island was the name James Cook gave the islands when they were discovered by him in 1778 to honour his most significant benefactor John Montagu, 4th Earl of Sandwich. These two butterflies are derived from Elwes´ collection but when and by whom they are collected is unknown. The third specimen is labeled Honolulu and belonged to Lord Rothschild's private collection. This male as far as I can understand from the labels on the butterflies comes from Felder's collection and bears the label "Felder collection Ponteni Wallengr.". Possibly this specimen, but perhaps also the two others, can also originate from the Swedish Scientific Sailing trip round the World with the frigate Eugenie in 1851 – 1853. More about that later.

I first saw this mysterious butterfly on a visit to the Natural History Museum in Stockholm in 1972. Over the years I have occasionally tried to solve the mystery with the help of a lot of friends from all over the world. The mystery being as to where the species was actually collected. The butterfly Colias ponteni has, after all, been considered the world's most sought-after butterfly and at the same time probably the only described butterfly that you do not know in which continent it was collected! In addition, I had the pleasure at the Museum of Evolution in Uppsala, in connection with the museum being re-opened after a comprehensive restoration, in finding two unknown males of the species and a pupal case of a parasitized pupae whose origin is also probably derived from the described species Colias ponteni. In total, we now have 11 specimens, 7 males and 4 females divided into 4 museums, 3 in Sweden and 1 in England. But where were they collected? Hawaii? along the Strait of Magellan? Tahiti? Valparaiso? San Francisco? Galapagos Islands? Unfortunately, we lack the knowledge of whom or which people really made these collections as well as when and where this was done. The questions are many but the answers unfortunately are few, which opens up for extremely interesting speculations. A dream scenario for me as an investigator even in my civilian work.

My own reflections

I think I have now come up with a number of indications that point to the Hawaiian Islands as the most likely place where the butterflies were collected. However, with this article I would like to show that there are actually circumstances that may possibly speak against this assumption.

The assumption is based on a series of indications, and careful studies of many possible locations along the route of the frigate Eugenie from 1851 to 1853, and also a completed isotope study where some of

the collected Colias ponteni butterflies were compared to butterflies collected on both Oahu on Hawaii islands and in the areas along the Strait of Magellan. As far as I can see, everything suggests that Oahu, with the areas just outside Honolulu, being the place where the butterfly once existed. However it was eradicated shortly after the priest Samuel Pontén, probably together with the botanist Nils Johan Andersson and maybe even the expedition's zoologist Johan Kinberg, collected at least five, but possibly another one or even three specimens in midsummer of 1852. The reason for the extinction of this butterfly is very likely to be attributed to the new planting of sugar cane and other crops that were planted in the area around Honolulu on Oahu in the mid-1850s after the extensive European colonization. When these butterflies are said to have been collected, the original Polynesian population, mainly through various diseases that these colonists had brought with them, had been reduced from about 300,000 when Cook discovered the islands in 1778 to only 70,000 in the mid- 1850s when the Swedish frigate Eugenie visited Hawaii.

Why do I write and publish this article in spring 2019?

I decide to publish the results of my studies as I have heard that it is time to carry out new DNA investigations of all the butterflies that are found in the four museums where the species are represented. Hopefully, maybe my studies can also provide valuable information when it comes to analyzing and understanding the upcoming DNA results. I look with the utmost zeal towards what these modern DNA studies can provide. I participated more than 20 years ago in such an investigation. Unfortunately, at this time, the technology was too deficient in such old specimens, and would not give us adequate results in terms of kinship with other Colias species. Hopefully, the new DNA surveys may indicate Colias ponteni’s kinship and perhaps also show from where the species once arrived in Hawaii from. If Hawaii turns out to be the right place for the species? The parasitized pupa can hopefully give clues as to where this unique butterfly lived and if one can determine which parasitic species attacked the pupa and also which plant the pupa adhered to before hatching. However, there may still be a number of remaining questions even if one manages to determine the nature of the parasite and the plant. More about this below.