So, I discovered today that my starting to pupate Carolina sphinx caterpillar didn’t make it 🙁 and I’m wondering if you had any idea what kind of parasitoid wasp this might be. Here are the deets:
1) The caterpillar had begun to pupate between two sheets of paper towel, so I had easy access to check on her progress quite a bit. At no point did she have white cocoons on her body, so I did not suspect she had any kind of parasite ahead of time.
2) The adult wasps came out of a large hole in her body. It looked like there were four total.
Have you experienced this? The Googling I’ve done doesn’t seem to yield any results except for the usual “covered in cocoons” pictures.
That is indeed very strange. My experience with parasitoids has been with flies and wasps.
The wasps will either parasitize eggs, or pupate on the caterpillar:
Above: Assassin bug eggs (Zelus sp.) parasitized by wasps
Above: Braconid wasps parasitizing caterpillars. Left: Geometrid caterpillar (inchworm) Center: Dagger moth (naked pupa, no cocoon) Right: Vine sphinx
Above: Stupid wasps that parasitized my little caterpillar, so I never got to find out what species he was.
The flies will grow up inside the caterpillar, and then either emerge as larvae to pupate, or they will wait until the caterpillar makes a cocoon, then they will emerge, pupate themselves, and exit the cocoon as an adult.
Above: Southern Flannel Moth parasitized by Tachninid fly (maggot on the left). Fly pupated outside of the caterpillar.
Above: Tachinid flies parasitized Southern Flannel Moth caterpillar, pupated inside cocoon and freaked me out when I saw them come out D:
That said, my experience is by far not exhaustive, and these parasitic relationships are so complex (like some parasitoids will parasitize parasitoids… aaaaaahhh!). Even Bugguide throws its hands up in the air and gives up [link to their attempt to categorize parasitic wasps]. Maybe you’ve made an important discovery!
I don’t recognize your parasitoid. These things do tend to be tiny/microscopic, so it’s hard to make out the details in the photo. If I didn’t have any of your information, I would probably guess this wasn’t even a wasp. It *might* be a fly (maybe??), and if it is, that would somewhat match the patterns I’ve seen, except I have never known a full adult to emerge from a caterpillar. That’s very strange! Do you still have the wasps? Any chance of getting closer photos of these things?
August 8, 2018
I wish I’d gotten a better picture of the remaining parasitoids! I took the enclosure outside to take some macro pics in the sunlight before releasing them, but the three that were still alive saw an opening and decided it was time to bolt.
Ooh, further research: Maybe it’s a type of mummy wasp (Aleoides)? I’m looking at images of their victims, and it looks very similar to the way my caterpillar was left. Maybe it hadn’t begun to pupate, as I’d originally thought – it turned brown and fat, so I assumed it was starting the process, but the mummification looks closer to what happened.
I’ve seen mummy wasps at my house frequently, but I never really thought to look up why they were called that. I have found aphid mummies, but never caterpillar mummies!
Above: An aphid mummy. Exit “flap” visible on the aphids butt in the right photo (butt is at the top).
There’s a subfamily of wasps, Rogadinae, which all make mummies [link to bugguide]. The subfamily includes the Aleoides genus. The ones I see are Smooth-headed Mummy Wasps, Aleoides politiceps:
Bugguide said that this species is one of the largest mummy wasps, and one of the few that can be identified without a microscope. I didn’t find any photos of what their prey look like, but here is the mummy left behind by another species, Aleoides stigmator: [WARNING trypophobia alert, here be holes]
Mummy left by Aleoides stigmator wasps. Photo from iNaturalist – Source [link]
Interestingly, these wasps are braconid wasps. These ones just don’t bother burrowing out to spin cocoons like the more commonly known ones.
That is so much more interesting than tachinid flies!
August 9, 2018