After reading Margarethe Brummermann's blog post yesterday about bot flies, I became intrigued by the fuzzy, bumblebee-mimic deer bot fly pictured in the post:
Then I consulted Lynn Monroe's new book: "Desert Insects and Kin of Southern California: A Photographic Survey and Natural History - Anza Borrego Desert State Park" and became convinced that these bot flies might not only exist in the region, but that they might be out and about at this time of year.
So after meeting Gary's son Ted at the Mexican border to see him off on his Pacific Crest Trail adventure, Gary and I decided to take a hike at Lake Morena, convenient and close by. I did not really expect perfect "hill top" conditions (hill-topping is the habit of some insects of congregating at a high point like the top of a hill or mountain and often establishing territories, in an attempt to intercept passing potential mates). Bot flies are known for this behavior, and amazingly, after a false alarm, in which I thought a smaller carpenter bee was a bot fly (!), we actually FOUND deer bot flies perched and periodically flying about at a high point in the chaparral overlooking the lake!
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| Cephenemyia jellisoni, a Deer Bot Fly. This specimen was captured at Lake Morena, southern San Diego County, on April 20, 2013. |
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| Dorsal view of Cephenemyia jellisoni, deer bot fly. Lake Morena, April 20, 2013. |
These flies do not feed as adults, but after mating, females will deposit tiny larvae in the nasal cavities of Mule Deer. The maggots can reach as much as an inch in length, and will develop inside the respiratory passages of the deer. Later the maggots will be sneezed out, to eventually pupate in the ground and emerge as an adult fly. Apparently this does little harm to the deer, despite its repulsiveness to humans.
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| The "hill top" at Lake Morena. Rich chaparral habitat. |
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| Lake Morena, San Diego County, California. |
