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Saturday, February 28, 2009

Evidence of Mantis Egg Parasites

I was checking on the ootheca the other day . . . mantis egg cases, that would be. I know where three of them are/on the crow/under the picnic bench/on the gourd earth, and so I take a look now and then, mostly just to look because the mantis nymphs aren't expected to hatch for several months, in mid-summer. So I was surprised to see these tiny round holes in one of them (the one on the earth); they looked to me just like egg-parasite exit holes on glassy-winged sharpshooter egg masses.

I searched around the internets but couldn't find any information specific to southern CA; but as we know mantis egg parasites do exist here. I did find out about some Australian parasitic wasps which actually hitch a ride under the wing of a newly matured female mantis. The female wasp waits (up to several months) until the mantis has mated and is laying its eggs within the oothecum, then creeps down to the foamy mass and locates a mantis egg with its long ovipositor, dropping an egg there. It repeats the process and then the foamy covering hardens, protecting the parasites as they consume the mantis eggs.

During my search I also ran across The Art of Being a Parasite, by Claude Combes, which sounds like a fun book to read if it shows up at my public library. (3/1: fixed that link/sorry 'bout that)


Cindy said...

After I began finding those little parasite exit-holes, I started collecting all the fresh ooths I found in the fall, and protecting them in a paper bag or fine mesh bug tent over the winter. In the spring, I put the ooths out in the yard again.

I wasn't aware that the parasite wasp might be hitching a ride on the female mantid, and if this is the case, it shoots holes (no pun intended) in my strategy. But so far, none of my protected egg cases has suffered from parasites.

vanessa cardui said...

well, I'm keeping an eye on the others. I think I might take in the one with the exit holes, and confirm how many mantids hatch, if any do. That's interesting that your protected ones have been parasite-free. It's a bit hard to believe (though not impossible) that you just happened to collect those that weren't already parasitized. So maybe "our" parasites here in OC don't use the hitch-a-ride gambit.

Cindy said...

Well, I'm lucky to find just one or two a year, in addition to those from any captive mantids I may have, so that could be why. Also, a mantid may make more than one ooth if conditions are favorable. Maybe they don't always get hitchhiked twice.

alaina said...

I collected 12 mantis eggs this spring. The majority of them show evidence of something erupting from them. Not the mantises. Over the winter & through early spring I store my eggs in opened (on 2 sides) zip lock bags. I have discovered small black wasps (2 of them) in these bags.