Currently viewing the category: "Tachinid Flies"
What's That Bug? does not endorse extermination

Subject:  Black fly, yellow stripe on head
Geographic location of the bug:  Westfield, MA, USA
Date: 07/11/2020
Time: 01:47 PM EDT
Your letter to the bugman:  We have a hybrid hydrangea that blooms through July.  Some days there are many dozens of insects enjoying the blooms.  I cannot identify this one.
How you want your letter signed:  Steveb

Featherlegged Fly

Dear Steveb,
This is one of the parasitoid Tachinid Flies in the genus
Trichopoda which are known as the Featherlegged Flies, and it is probably Trichopoda lanipes which is pictured on BugGuide.  According to BugGuide, it preys on Leaf Footed Bugs in the family Coreidae.

What's That Bug? does not endorse extermination

Subject:  Karner blue butterfly
Geographic location of the bug:  Albany Pine Bush, Albany, NY
Date: 05/27/2020
Time: 05:43 PM EDT
Your letter to the bugman:  Hi What’s that Bug!
Here’s a mystery for you. I’m quite certain this is a Karner blue butterfly, Plebejus melissa samuelis. You may be aware that our Albany Pine Bush in upstate New York is one of the few habitats this endangered subspecies can thrive, since its larvae feed only on the wild blue lupine that grows here. I saw quite a few Karner blues out among the lupines on this visit! None of our other local blues have that much orange along the wing, so it has to be a Karner.
The mystery: what the heck is going on with its abdomen? What is that orange stuff at the end? I thought it might be laying an egg, but as far as I can tell their eggs are light gray or white, not orange. And anyway it’s not on a lupine–I think the plant is a raspberry or blackberry. It stayed in this position for a couple of minutes before fluttering off, and I didn’t realize there was anything weird until I looked at the photos.
I’ll also include a better image of a different individual for your enjoyment. This little guy seemed to be more interested in lapping up my sweat than anything else–I tried to coax it onto a lupine, but it wouldn’t leave!
How you want your letter signed:  Susan B.

Male Karner Blue exposing his genitalia

Dear Susan,
Though we are quite excited to post your Karner Blue images, we will start with the mystery.  We don’t know what that is, but we suspect it is not a good thing.  We suspect this might be evidence of parasitism, possibly Dipteran, meaning a type of fly.  Though we don’t often site Wikipedia, it does provide this information “A tachinid fly,
Aplomya theclarum, has also been listed as a Karner blue butterfly parasite.”*  We will attempt to get a second opinion on this matter.  Meanwhile, we really are thrilled with your images of Karner Blues.  Not only was it described by one of Daniel’s favorite writers, Vladimir Nabokov, it is a new species for our site that currently contains over postings. 

Karner Blue

*Haack, Robert A. (1993). “The endangered Karner blue butterfly (Lepidoptera: Lycaenidae): biology, management considerations, and data gaps”. In Gillespie, Andrew R.; Parker, George R.; Pope, Phillip E. (eds.). Proceedings, 9th central hardwood forest conference; 1993 March 8–10; West Lafayette, IN. Gen. Tech. Rep. NC-161. St. Paul, MN: U.S. Department of Agriculture, Forest Service, North Central Forest Experiment Station. pp. 83–100.

Thank you so much for your reply! I was pretty excited to spot so many Karner blues that day—usually I don’t get out to the Pine Bush until later in the year, when they are scarcer. I’ll be going back early in the morning to see if I can catch them basking with their wings open.
That’s a good thought that the orange mass may be parasites. I hadn’t even considered that it could be somebody else’s eggs. I’ve sent the image along to the staff at the Albany Pine Bush to see if they can identify it for sure, and also so that they can document it, since they monitor all the happenings with the wildlife there.
Susan B.
Karner blue update—I heard back from the entomologist at the Albany Pine Bush regarding the weird orange mass on my Karner blue butterfly. Here’s her response (with her permission to share):
“Hi Susan,
Thanks for sending along the images! I have to tell you, what you are seeing there at the end of the abdomen is rated PG-13. What you captured is the genitalia of a male karner. They don’t usually flash them like that, it is unusual to see as they are usually kept internally until mating. An interesting thing to document, for sure! Thanks again for sharing.
Best,
Dillon”
What a relief to hear that I was only witnessing a bit of lepidopteran exhibitionism, and not a parasite infestation (fascinating though that would be)!
-Susan B.

Thanks for the fascinating update Susan.  It is interesting that Nabokov classified many of the Blues using a theoretical taxonomy that he devised after dissecting the genitalia of museum specimens.

What's That Bug? does not endorse extermination

Subject:  Bristle Fly
Geographic location of the bug:  Oakdale NSW
Date: 02/02/2020
Time: 06:58 PM EDT
Your letter to the bugman:  Can you please confirm if the attached image is of a Bristle fly. The markings are slightly different than those on your website.
How you want your letter signed:  Bristle fly?

Tachinid Fly

This is a Tachinid Fly in the family Tachinidae, and some species are known as Bristle Flies because of the course hairs that cover the abdomen of many species.  We believe your individual might be Formosia speciosa which is pictured on Brisbane Insects.

What's That Bug? does not endorse extermination

Subject:  Strange looking housefly I saw in my garden
Geographic location of the bug:  Kelowna, British Columbia
Date: 05/27/2019
Time: 08:38 AM EDT
Your letter to the bugman:  I took a photo of this fly I saw on a plant while I was weeding my flower garden on May 24th 2019. It looks like a cross between a housefly and a ladybug. I took several photos, but in the first one you can see the line of black dots on it’s red back.
How you want your letter signed:  Samantha C.

Tachinid Fly

Dear Samantha,
This is a beneficial Tachinid Fly a member of a family of parasitoid flies with larvae that prey upon a variety of arthropods.  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.”  We believe based on this BugGuide image, your individual is in the genus
Gymnosoma.  According to BugGuide:  “Hosts are Pentatomidae bugs.  Adults take nectar.”  Pentatomidae includes Stink Bugs and Shield Bugs, many of which are agricultural pests.  The Master Gardener Program of the University of Wisconsin-Madison has a nice page on Tachinid Flies.

What's That Bug? does not endorse extermination

Subject:  Colourful fly
Geographic location of the bug:  Oak Beach qld
Date: 02/14/2019
Time: 09:17 PM EDT
Your letter to the bugman:  Spotted this beautiful fly.  First time I have seen one like this.  Just wondering what it is
How you want your letter signed:  Rhonda

Tachinid Fly

Dear Rhonda,
This is a parasitic Tachinid Fly, and 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. Some 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.”  Your individual resembles this colorful Tachinid Fly from New Guinea.  The Museums Victoria Collection has a similar looking individual identified in the genus Rutilia.  This Rutilia species on FlickR also looks similar, but not exactly correct.  The Brisbane Insect site has images of several species in the genus Rutilia, and we believe the genus is correct, but we are not certain of the species.  Tachinid Flies are called Bristle Flies in Australia.

What's That Bug? does not endorse extermination

Subject:  Bristle Fly?
Geographic location of the bug:  Mittagong NSW
Date: 01/26/2019
Time: 10:42 PM EDT
Your letter to the bugman:  Saw this today. Is it a Bristle Fly?
How you want your letter signed:  Thanks and regards, Paul

Tachinid Fly

Dear Paul,
This is a Tachinid Fly in the family Tachinidae, and members of this family are sometimes called Bristle Flies in Australia, but we are not entirely certain if that name is used for the entire family or just a few species, like
Amphibolia vidua which is represented on our site under the common name Bristle Fly.  We believe your individual is a different species, possibly Formosia speciosa, which is pictured on the Brisbane Insect site.

What's That Bug? does not endorse extermination