There is a drawback to ladybugs I'm afraid.
I copied and pasted the following article from the Learn 2 Grow website,
http://www.google.com/url?sa=t&sour...dybugs&usg=AFQjCNFhA5IBw7Ka5dObZ0NL661roFgxYA
"Where do these ladybugs come from?” Most ladybugs for sale are the convergent lady beetle, Hippodamia convergens, and sadly, they’ve been “harvested” from natural winter aggregation sites.
What does this mean exactly? Well, in the western United States, after the ladybugs have fed all summer, they head up into the mountains by the millions to spend their “off season.” While resting clumped together by the thousands, collectors come along and scoop up the hibernating ladybugs. Next, these dazed beetles are either packaged and shipped out to retailers or they’re held in refrigeration to break their hibernation. If they aren’t held to “break” their hibernation cycle, they won’t lay eggs when released. This dormancy stage must be broken for the life cycle to continue.
If you do purchase wild-harvested ladybugs after they’ve had their dormancy broken, what will happen? Most of the time once they’re released, the beetles migrate before starting to feed or laying their eggs. In most cases, they’ll migrate right out of your garden. Unfortunately, this means little or no control for your pests.
Another concern is that harvested ladybugs may have been parasitized by a small wasp called Perilitus coccinellae. The wasp develops as an internal parasite, killing the ladybugs. There is no test for the parasite, so you may inadvertently be adding them to your garden when you buy your ladybugs.
The short point here is that purchasing wild-harvested ladybugs, which almost certainly what you will find at retail outlets, will not do much good for your garden, and it may introduce non-native species into your local ecosystem. Additionally, purchasing these ladybugs may contribute to the decimation of the wild ladybug populations. This is an unfortunate situation because some collectors are taking advantage of an opportunity to literally pick money (the ladybugs) from the landscape, and they don’t see the longer term consequences. If more people know about this reality and stop purchasing wild-harvested ladybugs, this problem can be stopped."