The Xerces Blue is Not Impressed With You

If your species has a royal name, start looking over your shoulder.

Named after the Persian kings of 5th Century BC, the Xerces blue butterfly is yet another creature that went extinct in living memory. Well, your grandparents’, anyway.

The first North American butterfly to be wiped out by habitat destruction, it vanished around the early 1940s, and there are only a few pinned specimens left in the world. But what a specimen it was.

Winged wonder

The Lycaenidae, or “gossamer-winged butterflies” are already known for their flashy colours and wing spots, and Xerces was no exception. The males had an iridescent lilac-blue on the outside wing, with large white spots with black “pupils” on the chestnut-brown inside. The females were generally duskier in colour, although this may have been due to the specimens’ age. Nonetheless, Xerces was peculiar in that there were up to 5 different variants, with both spots and pupils ranging in size.

Given this was from one small population, it’s an impressive level of mutation, but ticks one of the boxes for “in danger of annihilation” – being restricted to one area. I don’t blame it though, because who doesn’t love the beach?

It’s also a great place to show off your bizarrely hulking body shape.

Coastal homes are at a premium. Especially for insects.

Xerces could have spent as long as February to June flitting about the sand dunes of San Francisco, laying its eggs on low-growing plants like lotus and lupins, especially in the Sunset District. Sounds like a lovely place to live, doesn’t it? Yes, so we slapped houses all over it leaving poor Xerces nowhere else to go, and its favourite baby food, a specific kind of lotus, was highly strung and didn’t cope well with soil disruption. That wasn’t the only kind either.

The winds of change

Robert Langston’s paper in 1969 suggested a change in climate might have had a figurative hand in sweeping it away. With warmer winters and cooler summers here than the mainland, any spike in severity would probably also have spelt doom for these flutterers and the plants they fed on.

For a short time Xerces was still recorded at Fort Funston, but that proved decidedly less fun when it was bulldozed to the ground. It was at the former military base at Presidio, just 12 km (8 miles) further north, that the last specimen was netted in March of 1941. Not by some curious children or upstart, but etymologist W. Harry Lange no less, who later lamented “I thought there would be more. I was wrong”. I’m not sure if accidentally capturing the last of a species you’re studying is amazingly lucky or just embarrassing.

To add to the awkwardness, some of Xerces’ former haunts are now part of the ecologically protected Golden Gate National Recreation Area. Will we ever learn? Well, in this case, maybe.

Iconic insect

To counteract our horrendous actions, we set up The Xerces Society in 1971, specifically for endangered butterflies and other insects. In 2005, the society drew up a list of threatened US species, and in 2011, the Bohart Museum of Etymology in California, home of one of the last specimens, made the t-shirt “And Then There Were None” to showcase the Xerces blue butterfly as a warning.

Although Schultz et al.’s 2013 study found that there was no official body tracking conservation efforts, it’s a step in the right direction, and since many people (myself included!) sometimes find bugs gut-wrenching, a stunning butterfly is just the symbol needed for their conservation. Because if we won’t save the beauty, what hope has the beast got?

TLDR

Latin: Glaucopsyche xerces

What? Extinct butterfly with iridescent blue upper wings

Where? Sand dune areas of San Francisco, from Twin Peaks to North Bridge, but at one point concentrated in the Sunset District

How big? Wingspan of 2.8-3 cm / 1.1-1.2 inches

Probable motto: If you hadn’t liked the beach so much, my life wouldn’t have been one.

They look beautiful. Is there anything I can do to help them?

It’s too late for Xerces, of course, but The Xerces Society are working to prevent other species from disappearing into the ether.

Just to prove I’m not fibbing:

Foley, Jonathan. 2015. “Global science“. Boom California.

Garvey, Kathy Keatley. 2011. “And then there were none: Bohart Museum remembering Xerces blue butterfly in effort to help preserve other species”. University of California.

Hale, Katherine. 2016. “A tale of two butterflies“. EcoBlog.

Langston, Robert L. 1969. “A review of Glaucopsyche, the silvery blues, in California (Lycaenidae)“. Journal of the Lepidopterists’ Society 23(3):149-154.

Schultz, Cheryl B. et al. 2013. “Restoration, reintroduction, and captive propagation for at-risk butterflies: a review of British and American conservation efforts“. Israel Journal of Ecology & Evolution 54(1):41-61.

Showers, Paul. 1975. “Signals from the butterfly“. The New York Times.

Tilden, J.W. 1956. “San Francisco’s vanishing butterflies“. The Lepidopterists’ News 10(3-4):113-115.

Tilden, J.W. 1965. Butterflies of the San Francisco Bay Region. University of California Press.

Xerces blue“. No date. Florida Museum.

Featured image credit: Florida Museum of Natural History. Photo by Kristen Grace

3 comments

  1. A rather sad post. Even now in the UK some species of butterfly are under threat due to habitat loss/change. One ray of hope was the re-introduction of the Large Blue to the south west after becoming extinct in this country, and it has been a huge success. This should be a guide for the future, fingers crossed.

    Like

    1. Yes, that’s great to hear! It was outside the scope of this post, but the Schultz et al article did compare conservation practices in the UK with the US, and in the UK, at least at that time, it was more focused on things like moderate grazing and coppicing, whereas in the US it was mostly about removing invasive plant species and planting more native ones. I remember seeing hundreds of tortoiseshell, peacock and red admiral butterflies when I was a child, but now I’m lucky to spot a cabbage white!

      Like

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