Rodent Bot Fly

Subject:  black spotted white bumblebee?
Geographic location of the bug:  pennsylvania
Date: 07/13/2019
Time: 06:58 PM EDT
Your letter to the bugman:  I spotted this bug after it landed on a blade of grass and hung there behind me. I originally thought it was a carpenter bee because that’s what it sounded like flying by. However, when I turned around and saw what it I was shocked. It was pretty docile and hung out upside down for about 8 minutes of the same blade of grass, and was calm enough to call several people over to it to check it out. I am so interested to see what this is!
How you want your letter signed:  Lyndsey Mertz

Rodent Bot Fly

Dear Lyndsey,
This is a Rodent Bot Fly in the genus Cuterebra, but we would require an expert opinion regarding the species.  We will attempt to contact Jeff Boettner for assistance in this matter.  According to BugGuide:  “Females typically deposit eggs in the burrows and ‘runs’ of rodent or rabbit hosts. A warm body passing by the eggs causes them to hatch almost instantly and the larvae glom onto the host. The larvae are subcutaneous (under the skin) parasites of the host. Their presence is easily detected as a tumor-like bulge, often in the throat or neck or flanks of the host. The larvae breathe by everting the anal spiracles out a hole (so they are oriented head-down inside the host). They feed on the flesh of the host, but only rarely does the host die as a result.”  this is our first Bot Fly image this season.  They are such unusual looking creatures and they are frequently mistaken for Bumblebees.

Rodent Bot Fly
Photo of author


BugMan aka Daniel Marlos has been identifying bugs since 1999. is his passion project and it has helped millions of readers identify the bug that has been bugging them for over two decades. You can reach out to him through our Contact Page.

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