Subject: Strange looking housefly I saw in my garden
Geographic location of the bug: Kelowna, British Columbia
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.
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.