Ladybugs and Other Nasty-Tasting Things

Susan and I live in California in a redwood forest, in a land called Big Sur (some of the time–we’re kind of disorganized and move around a lot).  One of several magical things about our property there is that it is a congregation site for ladybugs.  Some times of the year, things look like the snapshots here, which were taken in summer of 2008.  They mass on railing posts and tree trunks, they lie in blankets under the forest duff, and sometimes you can’t walk across the deck without making a disturbing crunch-crunch sound.  On warm days they take wing in clouds, and end up inside the house, crawling all over you.  Susan once muttered, “You know, it’s actually kind of refreshing when you feel something crawling on you, and you look down and it’s a spider.”

Convergent Ladybird Beetles (Hippodamia convergens) in our forest duff in Big Sur

And not many people know this:  Those little suckers bite!  Okay, it’s not a bad bite, but when they’re boiling up your pant legs from the leaf litter it can get annoying.

But of course, I’ve never been able to stay annoyed at one of nature’s miracles for very long, so I did what I usually do and looked up some stuff on ladybugs.  Here you go:

They’re actually called the convergent ladybird beetle (they’re actually called Hippodamia convergens, but let’s not go to the Latin place), and almost everything we know about them, we know because of the agriculture industry, so I’m awash in information about the movements of the California Central Valley ladybugs, but no wiser about the ones on our Big Sur property.  Oh, well.  Still, the Central Valley story is a pretty good yarn, so listen up:

In the farm fields of the Central Valley, the ladybugs gorge on aphids in the spring, mate, lay eggs and die.  The larvae hatch and gorge on more aphids (this is why farmers know a lot about ladybugs and consider them to be extremely cool).  When they turn into adults in June, they fly east to the Sierra Nevada mountains to over-winter, and that’s pretty interesting because beetles, as a group, are pretty crummy flyers, and ladybugs are no exception.  So how do you migrate hundreds of miles by air when you have no compass, no brain to speak of, and you’re a bad flyer?  Well, here’s what they do:  they simply fly upward.  Period.  That’s all they do.  Ask a ladybug how she does it and that’s all you’ll get back.  But here’s what happens:

At altitude a favorable wind takes them and carries them east toward the mountains while they just continue flying up because that’s all they do, and an interesting thing keeps them from ending up in outer space:  Like most cold-blooded animals, they go into a stupor in the cold, and it gets cold with altitude (4.5 degrees farenhiet colder per thousand feet).  This is fun because it proves that evolution is nothing if not innovative.  The evolutionary process invented the concept of turning a problem into an opportunity, and they have actually made that stupor thing work for them.  They wouldn’t be good enough flyers to maintain a consistent altitude on their own, but what happens is that at several thousand feet, when it gets so cold that they can’t function, they fold their wings and drop like little pebbles for a thousand or more feet until they warm up, then they come to and start climbing again because that’s all they do.   The result is an eastward path that occilates up and down by about a thousand feet, staying in the general vicinity of 6,000 feet, give or take a thousand.  Eventually, they simply run into a mountainside, and consider themselves to have arrived.

All summer they move down the mountains in the canyons, then they hibernate under the duff or the snowpack at about 2,000 feet of elevation, and when they wake up in the spring they fly back west to the farm fields to do it all again.  This time, though, there’s no Sierra Nevada mountain range to stop them, so they just fly until it turns dark and cold, and then they fold their wings and drop all the way to the ground.  The result is that the ones who leave early in the morning make it the farthest and populate the western Central Valley, while the ones who leave later don’t get as far and end up more in the east.

They’re pretty interesting creatures.  If you disturb a plant that they’re on, they will drop off, and it will look to you like they just had a poor grip on things, but actually it’s done on purpose.  It’s a defensive move, and if you look at where they fell, you’ll find that they’re lying there playing dead.

But actually, they have almost no predators, because they taste nasty.   They excrete blood from their leg joints when they’re disturbed, in a process called reflex bleeding, and the blood has an alkaloid in it that tastes like hell, and is toxic.  Their bold orange and black markings are considered warning coloration.  A bird will try one once, and will not soon forget that look.  It’s thought that they acquired the coloration in the Cretacious period.  They’re a much older animal than that, but the Cretacious period was when birds began to become important predators.

And a friend of mine pointed out something else that’s fascinating about the ladybug: we all love them.  The most squeamish person in the world will love ladybugs.  Everybody thinks they’re cute, and no one minds when they crawl on them.  And I’m as irrational about it as anyone else.  If that were any other insect massing on our property in those numbers, I would be absolutely horrified.  And that one, Ranger Randy cannot explain for you.  I love all things natural, but I politely avoid the subject of how my mind works.

Folks collect them in the Sierras, literally by the gallon, and sell them to nurseries, who sell them to gardeners.  The collectors get twenty bucks per gallon (a gallon is about 70,000 ladybugs), and they can make up to $1,000 per day.  We have never collected or sold ours, and would not dream of doing that to the creatures.  (We’re unkind enough to them every time we have to walk across the deck.)  And anyway, there’s a fallacy to releasing ladybugs in your garden.  Remember where they were in their life cycle when they were collected:  The next thing they do will not be eat—it will be fly.

Now you know.