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This robber fly was one of those that I actually remembered seeing from years prior to our studies and I was waiting to catch one to find out what it was. I had recalled that instead of the fat Laphria antennae it had a thin wispy one. Note that it is a big bumblebee mimic like Laphria. I personally think it is an even better bumble mimic than most Laphrias. I have watched these now in heavily flowered areas around bumblebees to clarify the question of whether the mimicry is there to improve bumble predation or to protect this robber from other predators that may avoid bumblebees. And I can say that I have yet to see this robber, Mallophora orcina, take a single bumblebee. I did see one knock one down and abandon the effort. And saw another try to take another Mallophora with equal ineffectiveness. Lavigne's database of prey and predator records quite a few bumblebee, honeybee, wasp and yellow jacket kills for this species. I will just have to watch longer I suppose. |
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When I caught this animal I had hopes it might be the Holy Grail of robber flies, Dasylechia atrox. Dasylechia also has the bumble look and also has a thin antennae. Mallophora has wing veins like a Promachus (see the Fritz-Geller robber link for anatomy schooling) which was astounding to look at on this bumble creature. Dasylechia is a genus with a single robber species and it is a very primitive one apparently. At present there have been only thirteen collected in all of North America. Most of these are from Ohio. But also as far away as Iowa and Utah. Obviously, the distribution is poorly known, not to mention the biology. Described in 1884, the only Michigan specimen (in the excellent Michigan Robber summary paper from 1975) was taken in 1888. Subsequently, several photographers on bugguide have discovered this species. See that selection of photos there. Now from six states in the Great Lakes region. |
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In July of 2005 I received an email from a Biologist at the Balcones Canyonland's NWR in Texas. A local gardener had some 'giant flies' emerging on her property. She described them as being 'fairly common' as they emerged from her compost heap. She apparently even had the pupal cases of some of them. She turned some over to the biologist, Chuck Sexton, who proceeded to key them to Mallophora after recognizing that they weren't just any flies, they were robber flies. This is no small feat, keying in the big eastern genera key without some fly experience. Maybe he had some. But this is indeed Mallophora leschenaulti, one of the largest Asilids in the US. This is a scan and not a photo but I brightened it up for improved viewing (thanks to Gayle Strickland for further photoshop enhancements). Interestingly, here is what Bromley had to say in his Robber Flies of Texas paper from 1934 about what was then known as Mallophora belzebul:
This huge species is represented
in Texas in the U. S. National Museum by
And from Nancy Radding, a master naturalist in the Austin area this info:
she actually lives in the south
part
Interesting that some of
these may have been storm borne from south of the border. Impressive insects.
It is more likely that the imported pig manure or compost in the first site
was the method of import. I vote for Belzebul's Bee-eater as the common name.
And now in 2013 we have bugguide records from Houston to San Antonio to
Austin and one up just south of Dallas. It is possible that further
movement of compost could result in emergence elsewhere. |
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This is a shot I had kept and was previously taken in the Austin area by John Ingram. I believe it is the free-flying adult of this same giant. Texas has a third species of Mallophora that is slightly smaller than M. orcina and is brownish. |
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In July 2005 I heard from another Austin, Texas resident who communicates with the name larvalbug for her internet activities. She also has the monster Mallophora in her yard. They were reemerging in July of this year. But she had shots of this egg-laying activity from 2004. This is the first time I have seen any Asilid with an eggmass associated with its eggs. The rest have just soil dispersed (Diogmites) or implanted eggs in plant stems or flower heads (Promachus and various Efferia). Patrick Coin has now found Megaphorus minutus making a very close imitation of this mass in NC. |
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Here is the completed egg mass. And apparently the 'hatchlings' have either a long way to fall or they must crawl to the soil at some point. This is unknown. |
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This is a pupal case post emergence from larvalbug's yard. |
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And her very fine adult shot. Her description: "I'd sort of forgotten about these robber flies until this morning (2005), when I went out to hang up some laundry. I found 3 that had just emerged from our lawn. This is where they are easiest to find, since they are pretty obvious against the grass and are still slow because of having just emerged. I can almost always find their pupa shells. They have a hard time getting airborne, but I simply pick them up and hold them several feet off the ground and they fly away with no trouble. As your page states, they are monster flies - I've never seen any as big and was at first rather startled when I encountered them. I've never seen them catch any prey, but I did see one female lay eggs last year..." |
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And the commonest Mallophora in TX and the SW all the way to California. Though you won't find a better shot of it. This is M. fautrix. Taken by Eric Isley in central TX. Quite a bit smaller than the above giant and slightly smaller than M. orcina. Only species in TX with yellow abdomen to the tip. Originally called M. bromleyi. |
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And the 2011 model of fautrix from Texas again. Eric trying to improve and already fine shot. Burlier and hairier legged than our local orcina. |