L.A.'s Endangered Nature: Giant Flower-loving Flies

August 9, 2013

Ever heard of a fly that is big enough to be mistaken for a small hummingbird? Don’t worry this is not some horror movie featuring an overly large arthropod (think The Fly, Them, or the upcoming Big Ass Spider movie) this is real-life nature! Also, this is rare nature for Los Angeles; these flies are very, very uncommon in our region.

Ever seen this exhibit? Some of you may have heard of the Delhi Sands Flower-loving Fly, Rhaphiomidas terminatus abdominalis, a federally listed endangered species. In fact, this is the only fly on the U.S. Fish and Wildlife Service’s (USFWS) endangered species list for the continental U.S. (there are a bunch of listed flies from Hawaii). We even have a whole exhibit dedicated to these flies in a somewhat hidden stairwell (close to the ground floor elevators—have I ever mentioned how much I love our hidden exhibits?). However, the fly I’m talking about was thought to be extinct until recently! The coastal dunes in southwestern L.A. used to be home to a population of the El Segundo Flower-loving Flies, Rhaphiomidas terminatus terminatus.  It was thought that this subspecies was totally extinct, since there had been no sightings of the fly since 1965. However, research conducted in 2001, by George and Mattoni, found a small colony on the upper Malaga sand dune (on the Palos Verde peninsula). How could we have thought these flies were extinct for 36 years? It is not an easy question to answer. Maybe the entomologists weren’t out there looking (funding for research isn’t always available), or maybe they were looking in the wrong place, or at the wrong time. The biology of these flies is pretty intriguing. Adult flower-loving flies emerge in the summer for a period of only about two weeks! The rest of their lives are spent underground as eggs and larvae. The only way to find larvae is to a dig a large pit, and sift through lots and lots of soil. As you can imagine, this isn’t always feasible, especially in sensitive dune habitats that support other rare species. No wonder these flies went unnoticed for so long. If you are a visual person like I am, you can see how the range of the El Segundo Flower-loving Fly has changed over the last 100 years in our new Nature Lab. Check out our Life on the Edge interactive (directly underneath the taxidermied mountain lion). Here’s a teaser:

Guess what happens to the range of this fly when you press the "Today" button? Now that scientists have confirmed this fly is not extinct, I would have thought that it too would be on the USFWS’s endangered species list, but it is not. I am not sure why, something to contemplate and look into deeper mmmm...

(Posted by: Lila Higgins)

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