Tachinid Fly

Subject:  Bee-fly??
Geographic location of the bug:  Sanbernardino National Forest – southern California
Date: 11/09/2017
Time: 09:39 AM EDT
What the heck is this?? Lol
Found in Southern California on a rabbit brush bush.. feeding on the blossoms.  Nov 8, 2017
How you want your letter signed:  Sandy

Tachinid Fly

Dear Sandy,
This is not a Bee Fly.  It is a member of the family Tachinidae, and the only common name for members of the family is Tachinid Fly.  According to BugGuide, it is the “Second largest dipteran family (after Tipulidae), with ~1350 spp. in >300 genera of 4 subfamilies in our area(1) and >10,000 spp. in ~1600 genera worldwide; it is possible that only half of the species have been described.”  There are many genera that look similar, and the same with species, so we don’t believe we will be able to provide you with an exact species name, but it might be
Paradejeania rutilioides which is pictured on BugGuide.  There is a similar looking individual not identified beyond the family posted on the Natural History of Orange County site.  Tachinid Flies are parasitoids, and the female lays an egg on a host that hatches and feeds on the internal organs of the host, eventually killing it.  According to BugGuide:  “Larval stages are parasitoids of other arthropods; hosts include members of 11 insect orders, centipedes, spiders, and scorpions. Some tachinids are very host-specific, others parasitize a wide variety of hosts. The most common hosts are caterpillars. Most tachinids deposit their eggs directly on the body of their host, and it is not uncommon to see caterpillars with several tachinid eggs on them. Upon hatching the larva usually burrows into its host and feeds internally. Full-grown larva leaves the host and pupates nearby. Some tachinids lay their eggs on foliage; the larvae are flattened and are called planidia; they remain on the foliage until they find a suitable host.”

Tachinid Fly

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