Sloane’s Urania

A day-flying moth

Sloane’s urania, a strikingly beautiful moth with a wingspan of up to 7.6 centimeters, probably died out at the beginning of the 20th century because it could no longer find food plants for its caterpillars. What was special about Sloane’s urania was not only that, because of its coloration, it was considered “the most spectacular Urania species” (Lees and Smith), but also that the moth was active during the day. Most moths are nocturnal. By the way, the bright colors of the urania moth were not only aesthetic, they were above all a warning to predators, because Sloane’s urania was poisonous.

The English naturalist Philip Henry Gosse wrote two reports for the journal The Entomologist in 1880 and 1881 about the behavior of the butterfly species: Urania sloanus at home and Urania sloanus at home II. Sloane’s urania could be observed especially in April and June in large swarms while foraging, for example on avocado blossoms. The moths appeared shortly before sunrise, and once the heat of the day set in around eight or nine o’clock, they returned to their resting places. In the afternoon, when rain set in and it became cooler, they came back to the flowers.

Sloane’s urania was once very common in the Blue Mountains, a mountain region in eastern Jamaica. Reports claiming that the butterfly was also sighted elsewhere, such as in South America, could not be confirmed.

From about 1894 or 1895 onward, there were no more sightings of the moth, although some museums contain later dates such as 1908. The reasons for the sudden disappearance of Sloane’s urania are not clear, but plausible theories exist.

Sloane’s urania – fact sheet

alternative names	Sloan’s urania, Jamaican sunset moth
scientific names	Urania sloanus, Papilio sloanus, Papilio sloaneus, Cydimon sloanus, Leilus occidentalis
original range	Jamaica
time of extinction	early 20th century
causes of extinction	habitat loss, disappearance of the main food plant, environmental influences (e.g. hurricanes)

The disappearance of the food plant probably caused the extinction

In their study (2015) of a museum specimen from the Upper Silesian Museum in Poland, Pawel Domagala, Adam Larysz and colleagues name reasons for the disappearance of the urania moth. These include habitat destruction, the extinction of the main food plant, and environmental influences such as hurricanes, which Jamaica frequently has to contend with.

The scientists also note that this moth species must have been particularly valuable to collectors, especially at the beginning of the 20th century, because by that time Sloane’s urania had become very hard to find.

Certainly habitat loss also played a role in the moth’s extinction, but in a study on food plants and urania moths, David C. Lees and Neal G. Smith pointed out in 1991 that Jamaica still has a considerable amount of primary forest today.

Lees and Smith further state that the Jamaican cobnut (Omphalea triandra), regarded as one of the main food plants of the extinct moth, is still widespread in Jamaica.

The experts therefore assume that the caterpillars of Sloane’s urania relied primarily on Omphalea diandra as their main food plant. The reason: this plant used to be widespread in Portland, a parish in northeastern Jamaica. This also corresponds with the main range of the urania moth.

O. diandra has not been recorded in this region in recent years, which is why most scientists agree that the disappearance of the plant is connected to the extinction of Sloane’s urania.

Moth caterpillars depend on certain plants for food and development. Without these food plants, populations decline and the insects eventually go extinct. A similar fate also befell other butterfly species such as the Xerces blue or the Miller moth.

Named after the famous collector Hans Sloane

The British physician and naturalist Hans Sloane bequeathed his collections—from flora and fauna to coins and manuscripts—to the British Museum in London after his death. Several specimens of Sloane’s urania can therefore still be viewed there today.

Sloane was also the one who first portrayed the urania moth in 1725, namely in his book Natural History of Jamaika (Volume 2). The formal first scientific description of Sloane’s urania, however, was finally provided by the Dutch entomologist Pieter Cramer in 1779. He called the butterfly Papilio sloanus and honored Hans Sloane in the species name. The German entomologist Jacob Hübner then placed the moth in the genus Urania in 1816.

Moths of the family Uraniidae are mainly native to tropical regions of the Americas, Africa and Australia. Many of the species are known for their colorful, radiant colors, which make them look like true butterflies or day-flying butterflies. They were therefore given the English common name sunset moths. Six species belong to the genus Urania.

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