They don't stay put. They happily eat each other. I doubt they'd be an effective control of Jb's.

What york_rose said. The only thing I have actually seen eat a JB is an assassin bug. He sat there and munched on that beetle for a long time. At that rate, it would take many more of his type to make any kind of dent in the JB population.

For me, I ignore insects and beetles in the garden, and I let the good bugs (and birds) come in on their own to eat the bad bugs. In the 3 years since I sprayed insecticide, I have noticed that I have a lot better balance in my garden ... nothing is getting the upper hand. I tolerate the JB damage in the heat of summer, and I knock them into a bucket of water in the morning and/or evening if there are more of them than I can stand.

Connie

I'll tell you what I see eating JB's, and thats sparrows. I've watched them pick them off my roses and smash them to the ground before pulling apart and eating. That is why I gave up using insecticides years ago.

I guess I'm the only person here who's watched Mantis egg cases open.
It happens on sunny warm days, and all of a sudden there are these fragile almost transparent creatures (less than 5mm long) tumbling out. Then they look for places to hide, which is why they are better off in very shrubby places with lots of thin stems than on a HT with few hiding places.

It takes a lot longer than two weeks for these tiny predators to eat and molt and eat and molt etc. until they get to the three inch + length when we start noticing them.

I think their unappreciated value is in eating the smaller pests as they are putting on size.

Thanks for the replies....I wonder if they eat sawfly larvae.

I have mantises in my yard. The only thing I've ever seen them go after were my hummingbirds. I saw one hanging on the bottom of the feeder. I never knew they did that. I knocked him off into the flowerbed.

Mantids are generalist insect predators that are drawn to motion (I've paid very close attention to their hunting behavior before). If a younger (i.e. littler) immature mantid came across a rose slug that was moving around enough to catch the mantid's attention it would eat it.

However I very strongly doubt it would then decide to specifically go looking for more of them. Instead it would move on to whatever other small insect it noticed.

That's the way they work. When you buy mantis egg cases you aren't buying assassins, you're buying indiscriminate insect predators that eat and move on.

I watched one grab a Japanese Beetle and immediately release it.

I'm such a dork! When I saw the title of this thread, I thought you guys were going to be discussing the Mantis mini rototillers! LOL
I had tons of mantids at the mobile home park where we lived over 10yrs ago. It's considerably warmer down there. Up here in the Sierras, they don't do very well. I only bought an egg casing once when first we moved here. They just sort of disappeared. I've only ever seen maybe two or three adults since then. I think it gets too cold in the winter for them up here. I don't have Japanese beetles here, of course, but lots of other bugs. I do remember when we lived down the hill, one time I saw one chowing on a big fat katydid. They are interesting creatures. I wish they would thrive better here.

Beth, your temps are so much warmer than mine that I'd guess the cold isn't the limiting factor.

Maybe the difference is the kind of plants that are growing nearby.

Very rarely do I find Mantis egg cases on rose canes. Often I find them in Bridal Wreath thickets, in Privet Hedge masses (Privet hedge gone wild for at least 50 years), and sometimes in forsythia and winter jessamine shrubs. Those are very protective environs for hatching egg cases- something that the momma mantis looks for.

For me it's not a matter of "trying" them -- I've got 'em! For the past several years I've had at least 4-6 egg cases in the yard, and those are just the ones I can see. They are very fond of nesting in crape myrtles (lagerstroemia), to the extent that I have to be very cautious when I prune them.
They also love the rose garden, especially when I've interplanted them with Sensation cosmos -- the tall ones, 3 feet+ (and often ++). Last winter I wanted to move Sharifa Asma, but I didn't feel I should, since she had a mantid egg case on one of her canes. The little guys (and gals) generally stage their jailbreak in early to mid April, and after they do, they're almost microscopic -- less than ant size.
What do they eat? Mine love aphids, which makes be happy. But as many others have pointed out, they're indiscriminate. They also eat ladybugs and anything else that wanders into their vicinity. And yes, in mating season, decapitation happens. (Was it good for you too, dear?)

And here I was thinking this thread was gonna be about the Mantis mini-tillers....

Oh well...

Susan

Hey Ann, it might not be the temps, but possibly the elevation. I think I'm at around 1200ft. I think where we used to live it was like 500 or less. We had mantids popping out naturally all over the place. It was so cool. I miss them. I also miss my little black & white jumping spiders with the green eyes. They were really fun to watch, guarding the potted roses from bad bugs (and each other). I miss the toads too. Didn't have the deer there either. Dang, what am I doing up here?

I have preying mantises in huge quantities every year :D They are pretty darned impressive late in the season when they are huge!

Mine like the unmowed grass the best. That may be because I have so many darned grasshoppers each year, too. In those areas, I see a big preying mantis every 2-4 ft!

I do have some living in my roses, or I put them there and they like it. I still have too many JBs and grasshoppers -- just tons. But I have acres of grass, so numbers are a problem here.

Early in the year I have sawfly damage, but none later, so mantises may well be why that works out. I have other good bugs, too, so it's hard to tell.

I have frogs and toads and snakes, etc. too. And so many spiders :D

Apparently, 'locusts' and JBs really are kinda plague-like ;) Moles and voles, too, I think!

In any case, I'm sure the mantises help a lot. They sure are cool to watch while gardening :)

I agree with those who doubt the value of importing egg cases. My experience is that by the end of the summer, only a few remain. Not enough to control the Japanese Beetle attacks we endure. However, they are great photography subjects:

The moment of birth. If you look carefully, you can see a tiny hatchling.

{{gwi:232168}}

There's no question they have a big appetite:

{{gwi:232169}}

They don't always eat the targeted pest.

{{gwi:228436}}

Who could resist something so cute? Any question as to how they hang onto prey?

{{gwi:223315}}

Great pics. What is the fella eating in the second picture?

What is the fella eating in the second picture?

That's a katydid. They're pests (somewhat akin to grasshoppers & crickets), but typically not especially problematic ones.

There are plenty of egg cases for sale on Ebay.

Great photos, Harryshoe. I love to have them in the garden, whether they eat the right stuff or not. When they look at me with that triangular prehistoric head, I get the eerie feeling like they are sizing me up as prey. I get both green ones and brown ones. Does anyone know if these are two different species, or do they change color?

I think the brown one is an Asian type while the green is native. But, don't quote me.

Do you think that egg case sellers bother to look closely? Do they even know the easy way to tell if the case has hatched or not?

I do know that cases will last at least a year after they have hatched.

(Hint: where there is a slight offset that parallels the stem of the bush, when the babies have left, there are many, many fine slits in that offset.)

I tried for 3 years to get egg casings & never succeeded. Suppliers were always sold out by the time I could put them out in our yard. I have noticed the population on the increase in my yard after stopping insecticide use, and I'm happy. I love playing with mantises & I'm fascinated watching them. I also have to take great care when pruning because they blend in with stems. I've also nearly harvested their bodies out of our oregano and thyme.

They don't eat the JBs at my house, but they were pretty gung-ho about cucumber beetles. I think it's a timing issue. Cuke beetles show up late in the season, at about the time the mantises are at their largest.

I get green mantises and also purple ones. Are the purple ones the ones you are calling brown?

Check out this guy (not the type I get):

http://images.nationalgeographic.com/wpf/media-live/photos/000/291/cache/ngpc-wp-wk-8-3_29141_990x742.jpg
http://www.flickr.com/photos/gmitola/4665480899/

This is more like what I get:

http://www.flickr.com/photos/88926946@N00/94465696

I consider them a good thing in the garden, especially when they take up in the tomatoes.

We have lots of mantis in our no spray yard and flower beds. They love the roses, as well as other plants, and many times I accidentally spray them when watering, causing a huge mantid panic, while I mutter apologies (yes, I seem to speak out loud to insects more and more). My observation about mantis color is that they begin summer as green and by the end of the season with cold weather approaching, they grow progressively browner. They become very sluggish, and are usually hugely pregnant, too. We've had them clinging for days to our window screens during this time period, and moved a few, too. I find them endlessly fascinating.
Diane

Dang, Dimitrig! You have found an Italian comic opera mantis!! He/she is gorgeous!! Better yet, it looks like his/her entree for the day is some sort of scale or whitefly larva. Mine are much less flamboyant. Your "purple" guy/gal is also not quite what I get as brown. Here in Pasadena, at least in my garden, the brown ones are paler, almost buff color, and the green ones are a pretty vivid pale green. The green ones tend to have a more bulbous posterior, while the brown or buff ones are more pencil shaped.

The "bulbous" ones are the females. The "pencil shaped" ones are the males. The coloring has nothing to do with male/female. It's whatever sub species they are.

onederw,

I am also in Pasadena/Altadena up near Eaton Canyon, but I do not get any pale brown mantids. I do get the green ones, though. They seem to love my neighbor's mimosa trees. No idea what insects they are eating up there. I didn't realize they could fly until last year. I had never seen one do it until then.

I've been told that only one sex is capable of flight. Can't remember which one, though.

I have both the pale green and pale brown ones. I swear I caught one and brought it to my sister in a big coffee mug, and it had changed color. But that's been years, so I may just be confuddled. Don't quote me ;)

I had a green one on my car. The windshield to be exact. I didnt know how best to move him (her?) but certainly didn't want it to jump/fly at me.

Don't get me wrong...they are super cool....but that whole thing where the body never moves and the head rotates to look at you..... (((shiver))) I gives me the creeps I tell ya!!

I used a big piece of cardboard to transport him/her to safer grounds.

That head rotation just gives me the willies!!

Ronda

I've been told that only one sex is capable of flight. Can't remember which one, though.

This is certainly true of some other insects (such as the armored scales, for instance), but I don't for a moment believe this to be true of the mantids.