Rodent Bot Fly

Subject: Insect ID
Location: Odessa, Florida
June 30, 2015 5:21 pm
Dear Bugman, This morning in my front yard, attached to one of my Iris leaves was this really cool insect that I’ve never seen before. At first I thought it was a bumble bee but realized it wasn’t when I got a closer look. It has characteristics of a fly but also a bee. I hope someone can identify it! I’d love to know what it is. Thank you for your time and effort.
Signature: Brenda Wickham

Rodent Bot Fly
Rodent Bot Fly

Dear Brenda,
You have encountered some species of Rodent Bot Fly in the genus
Cuterebra.  We believe it is one of the fontinella group identified on BugGuide, which includes the Squirrel Bot Fly, Cuterebra emasculator, and the Mouse Bot Fly, Cuterebra fontinella.    According to Featured Creatures, the Tree Squirrel Bot Fly:  “is an obligate parasite of tree squirrels and chipmunks throughout most of eastern North America. The adult and other life stages are seldom seen; instead, what is usually observed from July through September or October is the outcome of infestation, namely the relatively large, fluid-draining swellings (‘warbles’) in a host’s hide caused by the subcutaneous larvae.”  We are going to copy Jeff Boettner to see if he can provide any additional information as he has assisted us in Bot Fly species identifications in the past.

Jeff Boettner responds
Hi Daniel (and please forward to Brenda),
Whatsthatbug is a good name for this one. This is a bit of a mystery. First off, this is a very freshly emerged bot…likely it had not flown yet and was still developing its color patterns and “hardening up”. That said, this one keys nicely to Cuterebra fontinella grisea which would be great except C. grisea is a northern bot (Canada south to NJ!) and not known from FL??? But the status of grisea is kind of still a confused mess. The general host for these guys is deer mice, P. maniculatus in the north. It is possible there is a very similar bot that is still unknown from FL in Peromyscus gossypinus? I would love to see the dna of bots found in this species of mouse in FL. So not sure what to call this for sure –but you are correct that it is likely a mouse bot in the Cuterebra fontinella group. Absolutely, a fabulous find and could be something very much unknown…Thanks for letting me know about it.
Jeff Boettner
[email protected]

Thanks for the information Jeff and we will pass it on to Brenda.

Thank you both so much for your help and information! Very informative and interesting! I have not seen this bug again since that morning unfortunately. I have two other pictures of it that I’ll email to you. I tried sending all three pictures initially but they wouldn’t go through.
Thanks again!
Brenda Wickham.

Thanks Brenda,
Additional images would be nice.  You should be able to attach to the reply instead of sending a new form.

Good Morning gentlemen, Here are the two additional pictures of the Bot Fly. I’d love to hear about any additional information you may discover regarding this particular species. We have a very large squirrel population here, so that would be my guess as to the host.
Thank you,
Brenda Wickham.

Rodent Bot Fly
Rodent Bot Fly

Thanks Brenda,
We will await any new information from Jeff, but the head on view might be helpful.

Wow Brenda! and Daniel,
This is a female fly by the space between the eyes. It is also almost for sure a mouse bot and not a squirrel or rabbit bot without going into details and for sure . It is nearly identical to Cuterebra fontinella grisea (which will likely become two species judging by dna). But this one is just enough different in looks (and way out of the known host range for grisea which should be north of NJ and nowhere near FL) that I really don’t know what to call it??? This could be a new subspecies of fontinella bot or possibly a new species?
I would love to try and get down that way in August to look for larvae and figure out the host? Not sure if I could get there this year…but will think about it. Its a really neat find. So glad you got multiple views of it. It is something very close to C. f. grisea, so likely using a southern Peromyscus mouse. I will start studying up on FL mice…
Very cool find. Very exciting find!

We are really excited to be able to post this unique find and to have such excellent, expert perspective.

Update:  July 14, 2015
I’m so glad the additional images were helpful! This is exciting!! We’ve been at this home for 6 years now and I’ve never actually seen any mice but plenty of squirrels, so that is surprising.  Please let me know if you do get a chance to visit this area. I’d be glad to have you stop by and look around! Do you think it’s possible that I would ever see this bot again or is it usually just a onetime event?  If there was any chance of spotting it again, my husband was curious as to whether I should attempt to capture it?

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