Sep 1, 2008

Hornworm Host

John took this photo of a wasp-cocoon infested tomato hornworm caterpillar near his him in Troy, NY, US.

I abominate the tomato hornworm (Manduca quinquemaculata). The caterpillars are enormous (up to 4" of undulating length), and the helicopter-moths (technically Hawk, Sphinx, or Hummingbird moths), are even worse, with a wingspan of 5 inches. I've had cats drag these monsters into the house and release them, forcing me to bring out my anti-aircraft weaponry to bring them down off the drapes.

But let's get back to the wasp-cocoon infestation I mentioned. Those little white rice-looking protuberances on the caterpillar are the cocoons of small braconid wasps (Cotesia congregatus). Earlier, the wasplings had been dining on the innards of the caterpillar, and the caterpillar could do nothing about it. But now that they're pupating, the caterpillar's life is almost over. It will die when the parasitoid wasps emerge. If you see a tomato hornworm so infested, and you hate them, as I do, leave it be. The wasps once hatched will seek out other hornworms. This is nature's way of protecting her tomatoes, eggplants, and potatoes.

Thanks, John.

8 comments:

Meg said...

Oh sweet jesus. Mental note to self: Never, ever click on Ugly Overload while eating lunch.

Will be back later. This is too gross/creepy/freaky to pass up!

niner said...

No matter how terrible the little hornworm is, it's still a sad story. I don't wish anything with such adorable little stubby legs such a fate. Why don't those wasp things like spiders? Now that, I would cheer for.

Anonymous said...

Meg: Don't even eat pita chips while on ugly overload *sick face* o-o

This has to be the one picture on UO that actually made me gag a little. It has my two most hated things in the entire world in it: Tomato worms, and bodily pupae infestation >.<

Ψ*Ψ said...

Adult braconids are really cute! They're smallish and dainty-looking. I used to sequence their DNA for a living (I think I even had one in the Cotesia genus).

Theodosia said...

If it's any consolation, the caterpillar isn't in any pain -- remember that the parasite trick is to keep the host healthy as long as possible in order to foster their own growth and development.

Anyway, I think the large hawkmoths are neato-cool, and I know somebody who catches them to bring them indoors for her cats to have substantial, moving toys to play with...

Anonymous said...

Ugly Overload has solved a mystery for me! I was sitting with a friend in her garden, when we spotted this crazy weird 'hummingbird' flitting around. It was very small for a hummingbird... and it appeared to have antennae. We agreed it was really weird.
Now, thanks to UO, I know it was a grown up version of this little fellow here (well, sans the wasplings).

I wouldn't like the idea of anything nomming on my tomato plants, but I think the 'helicopter moths' are pretty cool.

Sherry at SofN

Wanda said...

That is disgusting! Ick!

Aronwy said...

Oh. My. God. *starts scratching self furiously*