Wednesday, August 17, 2011

A New Garden Visitor - The Two-Spotted Digger Wasp


I wish I had a smartphone.  Then I would have been able to get a quick ID on the dozens of these guys tearing up my mint flowers, which would have led me to read quotes like, "should not be handled at any time," and "among the most painful wasp stings," and "complex venom with a long half-life."   Luckily, I didn't get stung.

Meet Scolia dubia, the two-spotted digger wasp, a close cousin of the gnar-rad Cicada Killer.  The digger wasp is an aggressive pollinator of mint species (as you can see from these pictures) and prefers to lay its eggs on the larvae (grubs) of small beetles like junebugs and Japanese beetles.  Which I am totally down with, since beetles are not good friends of my garden. Plus, this wasp is gigantic, so I'm going to not bother it, ever. Let's take a look at how this all plays out:


photo from hivemind.net
Ouchy!  Like the cicada killer, the digger wasp repeatedly paralyzes its "babies' host" so it can't escape.  Unlike the cicada killer, which captures and flies the cicada back to its own burrow, the digger wasp just expands on the grub's own burrow. 

The eggs mature and then the wasp larvae eat the still living grub.  That'll teach you to be a beetle.  Note to God: please don't send me back to earth as a beetle.

As I've written before about other native solitary bees and wasps (who pollinate our food!!), there are a few things you can do around your garden to help these fellas out.

1. Plant pollinator-friendly flowers and herbs in your garden.  Don't cut all of the blooms.


2. Don't use ridiculous amounts of pesticides on beetles. If, hypothetically, all the beetles were gone for two years, this species might become extinct. Which might be fine except that the beetles will return.




3. Don't try to eliminate the wasps by spraying your lawn or their burrows. That's just ignorant. In the case of the larger and ever-so-slightly aggressive cicada killer, I think a protective sign or fence or a warning to the kids might be warranted, but let the wasps work!


6 comments:

Alex said...

Cool wasp. I always think biological controls are neat.

If you're in need of any more wasps, I found a giant red wasp nest in my old hunting truck's gas tank cover yesterday. Though my reaction wasn't "oh cool!"...I think I substituted with some other four letter word as I ran away.

troutrageous1 said...

Damn that thing looks nasty. I appreciate all the wasps do, but if it was by my house, the only 4 letter word I'd be saying was RAID.

River Mud said...

Alex, I am not interested in any "big red wasp" of any variety. No thank you. Keep them in florida, with the velvet ants and everything else (we actually have velvet ants on the coastlines of MD and VA too).

TR, this wasp and the cicada killer are for real. They are "busy bees" and will do everything they can to ignore you, but again, I'd hate to see what'd happen if you cup one in your hands and shake it up!!!

biobabbler said...

Interesting. I saw a small wasp last night on the ground near my tomatoes which, however, are just a few feet from my mint (which I just planted last year), which has been blooming wildly. Lots of happy bugs buzzing around it.

Wasp had a deep, reddish body, like yours, and black wings. Maybe about 1 inch long. I observed carefully, and left. =) MIGHT have tried to take it's picture, but had a hot cat-sitting date, so had to clear out.

ANYhow, your timing is GREAT. Thanks so much!

Randy Emmitt said...

I see these wasps every summer on our apple and mountain mints. Glad to know what they are and how bad they sting. We enjoy them and other pollinators in the garden. Our bees, I have a beehive don't mind the company of these wasps at all. Yellow Jackets on the other hand are not honey bee friendly.

Outdoor Blogger Network said...

Beautiful close ups!
Ok, I'll think (try to) of the wasp in a new way after reading this post.
Thank you for sharing these ~
Rebecca