Tomato hornworm survived parasitic wasps

[bugmankeith]

I had a tomato hornworm on my tomatoes, and it has the wasp larave crawling out of it from tiny holes. I decided to pull them off gently just to see what happened. They were fastened on by a thin thread of silk.

The hornworm is still alive 5 days after this and growing, so I imagine only the adults end up killing the caterpillar?

 

[Villosa]

I believe the caterpillar is done for either way, with or without your help. To the best of my knowledge, the wasp larvae releases certain signals into the hosts body to prevent them from pupating, thus becoming giant eating machines.

 

[bugmankeith]

so then wouldnt it stay a caterpillar (like an axolotl never "matures") and keep living like that? I could always keep it inside and feed it hornworm chow and sliced tomatos just to see what happens.

 

[Villosa]

It could, see what happens. No harm in trying right? I'm pretty sure it'll just keep growing till it dies of exhaustion.

 

[v4climber]

Definitely take pictures as it grows, how cool would that be eh?

 

[froggyman]

so I imagine only the adults end up killing the caterpillar?

wouldnt the larva if unmolested eat and then leave the catipillar for dead with gaping holes in its side and the majority of its innards eaten? im just guessing that your intervention played a part in this

 

[bugmankeith]

See thats the funny part, when it had the larvae and cocoons on it I still observed it eating and pooing, if it couldnt digest food than how was this possible? I figured the adults must kill it with stings or something, because how else would the cocoon affect it's growth if I still saw it eating?

Or mabye this is just a rare case of the caterpillar surviving from not being infected with alot of them, each brood im sure varies in size and this caterpillar was big when they matured so mabye it wasnt affected as badly?

 

[froggyman]

See thats the funny part, when it had the larvae and cocoons on it I still observed it eating and pooing, if it couldnt digest food than how was this possible? I figured the adults must kill it with stings or something

its a little confusing i dont see any reason for the adults to kill it...maybe this is a case of a parasite that doesnt kill its host

http://en.wikipedia.org/wiki/Manduca_sexta#Larvae

 

[Galapoheros]

That's interesting. I've raised giant silkworm caterpillars that were infested with parasitic fly larvae, not the wasp, none made it. I've only seen empty wasp cocoons sticking out of some caterpillars but all the caterpillars I've seen were dead, but I've only seen a few. I've read the larvae eat around vital organs so the caterpillar won't die before they are ready to pupate. But I've seen an infested caterpillar make a cocoon before the fly larvae come out. I don't know much about the parasitic wasp. That'd be cool if that caterpillar makes it, that be the first time I've heard of that.

 

[Mat]

See thats the funny part, when it had the larvae and cocoons on it I still observed it eating and pooing, if it couldnt digest food than how was this possible? I figured the adults must kill it with stings or something, because how else would the cocoon affect it's growth if I still saw it eating?

Or mabye this is just a rare case of the caterpillar surviving from not being infected with alot of them, each brood im sure varies in size and this caterpillar was big when they matured so mabye it wasnt affected as badly?

Normally, when the parasitic wasp larvae emerge from their caterpillar host they are ready to spin their own coccons and pupate. They do not feed any further or attack or "sting" the host in any way.

In most instances the host dies when this happens as the parasites have eaten too much of the inside of the host for the caterpillar to survive. Vary occasionally you will get host caterpillars surviving, it depends on the number of parasites and the size of the host.

Can you take some pictures of your caterpillar for us and post them up here, I'd be interested to see how big it can get.

Matt

 

[bugmankeith]

When I search about the damage the wasps do this is what I have been finding.

The wasps will kill the hornworms when they emerge from the cocoons and will seek out other hornworms to parasitize.

If that is true and it's still eating im sure it has some chance at survival. I've raised hornworms, and this one is not yet near full growth, it's growth however is slow but it is growing. It's very aggressive (well mabye all wild ones are)
When I approach it it snaps it's jaws together making a clicking sound and will bite me and will "dance" for a few seconds like a cobra does sort of.

I'll get a picture of it. Right now it's still outside on the plant, I didnt want to buy hornworm chow and have it mabye not live and waste that money, and im not sure if I have enough leaves to keep picking, my tomato plants are very small. If it eats Petunia leaves though, then I know I have a good food source I have a bunch of those flowers and plenty of ripe grape tomatos.

I hope it doesnt get infected again.

 

[bugmankeith]

I got a picture.

From my observations the caterpillars head has slowly been turning from green to yellow, possibly from lack of nutrition or eating, it also is underweight.

I decided to keep it inside in a cage, I have placed inside petunia & tomato leaves, plus sliced grape tomatoes. The caterpillar instantly went to the sliced tomatoes and started munching away, I guess outside it was too weak to break the skin of the tomatoes on my plants.

So i'll just have to wait and see what happens. If it was not re-infested with more wasps it may stand a chance. If it develops slowly and doesnt pupate before it gets too cold, then i'll just keep it as a pet and feed it sugar water when it becomes a moth or hummingbird nectar.

 

[Mat]

Nice pic. I can see all the little black spots where the parasite exit holes have healed over. Any chance you could take some close ups of those too and post them up here, just for a photographic reference of what a "survivor" looks like.

Regards

Matt

 

[bugmankeith]

The caterpillar is already much greener and heavier in just 2 days! That yellow face you see is green now. I'll try to get a close up but I dont know how close i can get for it not to be blurry.

This is the best I could get.

 

[Warren Bautista]

Is it still alive?

 

[bugmankeith]

It was alive up to last week, but it had yet another infestation inside and didnt survive the 2nd infestation. If it had not been infested twice, it would have survived as it was growing and thriving after the 1st infestation was over.

 

[Galapoheros]

Awe that sucks. I kept 20 to 30 Polyphemus caterpillars outside and they all got infested really fast by a fly. Anyway, I guess it would have made it too if it hadn't been infested again.