A few days ago, I was pulling weeds from my gravel driveway. The night before, I had used the sprinkler to dampen the ground, making it possible to pull roots along with the plant from the otherwise sun-baked, hard ground. As I removed plants that morning, I discovered several ladybugs moving among the stems, apparently drawn to the moisture. I had to be careful where I pulled and stepped to avoid squishing or trampling ladybugs.
They’re so…cute! Tiny black-and-white faces, bright red shells with small black dots. They’re the only beetle about which I would use that descriptor. (The other beetle I see often – in my house – is the stink beetle, and there’s nothing cute about them. At all.)
I grew up calling these cute beetles ladybugs. In Britain and other English-speaking countries, they’re called ladybirds. Entomologists prefer the names ladybird beetles or lady beetles because they don’t fall within the classification of true bugs. But old habits die hard, so I’ll continue to call them ladybugs (as do many reputable websites).
As I watched those few ladybugs scramble across my driveway, I had a flashback.
Scene: High in the Cascade Mountains of Washington state, inside the Alpine Lakes Wilderness. An autumn overnight hiking trip with two friends and my dog (my first Malamute, a female I named Opus) in October 1987.
We ascended to an area mostly above tree line, camping near the shore of Lake Ethel at 6,050 feet in elevation. Larch tree needles were turning yellow, adding to the reds and oranges of huckleberry and other low-growing shrubs. We hiked cross-country, wherever we wanted, through an area of several small alpine lakes collectively called the Scottish Lakes (Lake Julius, Lock Eileen, Lake Ethel and Lake Donald), following our noses, scrambling up surrounding peaks to see what we could see. The air was clear and cool, and we could see forever, or so it seemed.
After scrambling through rock scree to bag yet another “peak” we stood admiring the stunning 360-degree views before sitting down for lunch. For some reason my friend Lance pulled a large boulder off a pile of similar boulders near where we sat. What we discovered under that rock was surprising and astounding, something I’ll never forget: thousands of ladybugs nestled on the dirt – and each other – and in the cervices between the other boulders in the pile! Exposed unexpectedly, they started moving, as one gigantic mob, crawling over and among each other. Realizing what he’d done and not wanting to expose them to the elements, Lance quickly replaced the boulder.
What had we seen? Why were so many ladybugs – those beautiful beetles I’d seen in my garden down in Seattle, at sea level – in a huge pile under boulders atop a mountain in the Cascade mountains at 7,000 feet in elevation? We surmised they must be hibernating, but beyond that we didn’t know anything about the ladybug’s life cycle, and…why there?
Many years later, when the internet made research easier, I learned that ladybugs do indeed hibernate, often under boulders on the tops of mountains, sometimes in hollow trees or logs. But that’s all I knew.
Seeing the ladybugs in my driveway, and remembering that long-ago discovery in Washington’s Cascade Mountains, I decided it’s high time (pun intended) I learned more. Here’s what a quick internet search provides:
A group of ladybugs is called a loveliness. (How cool is that?)
And when they’re hibernating in groups of thousands, they’re called an aggregation. (Not as cool.)
According to National Geographic, there are about 5,000 different species of ladybugs. Most of them eat plant-eating insects, such as aphids. In fact, they eat large numbers of aphids. In doing so, they’re valuable to farmers and gardeners, helping to protect crops and plants. “Ladybugs lay hundreds of eggs in the colonies of aphids and other plant-eating pests. When they hatch, the ladybug larvae immediately begin to feed.”
Here’s a nice video of the ladybug life cycle.
Their distinctive spots and red/orange colors are meant to be a signal to predators that they don’t taste good. Ladybugs can secrete a fluid from joints in their legs which gives them a foul taste.
According to the National Park Service, Capulin Volcano in New Mexico supports a wide variety of insects and particularly large populations of some that migrate to high elevations, including the Convergent Lady Beetle (Hippodamia convergens). It is named for the converging white lines on its thorax, and it usually has 13 black dots on an orange shell.
Each summer at Capulin Volcano, a new generation of lady beetle participates in a wind-carried migration and takes up residence at the highest points of the volcano. After feeding all summer, they hibernate through the winter on the volcano. Surviving beetles then catch a warm current off the volcano in February to the south to reproduce. Since the wind carries the lady beetle in its migration, it has a hard time controlling its destination and may go to aphid-rich fields near the volcano or maybe to wheat fields in Texas.
During a lifespan of a few months, the females lay up to 500 eggs on leaves and twigs. The eggs hatch and the larvae gorge themselves on the aphids. After the larvae clear the area of aphids, they pupate. Since the larvae usually clean the area of their favorite food, aphids, the adults migrate back to Capulin Volcano to await the opportunity when they too can go back to these aphid-rich areas and lay their eggs.
Ladybugs can’t fly if the temperature drops below 55 degrees F. They’ll literally drop to the ground if it’s too cold. And unlike migratory birds, ladybugs – solitary during most of their adult lives – don’t migrate in large groups, yet somehow hundreds or thousands of them end up in the same hibernation spot year after year, often depending on prevailing winds to help them fly to and fro.
According to KQED Science, “Scientists believe the behavior evolved as a way for a solitary species to reproduce and to cope with a limited winter food supply. After fattening themselves up, and before bedding down for winter, these ladybugs are getting together to take care of some final business — namely, mating. …Within the ladybug clumps, the movement is scrambling and unpredictable, not hierarchical as it is in a beehive or ant hill. Scientists think that the females — about half of the population, all of them previously unmated — may be selecting mates amid the chaos.”
Cornell University (which also has an Ornithology Lab and produced the wonderful app Merlin to help identify birds) hosts the Lost Ladybug Project. According to their website, the North American composition of ladybug species is changing, with native ladybugs becoming extremely rare, and ladybugs from other parts of the world increasing in numbers and range.
This is happening very quickly and we don’t know how, or why, or what impact it will have on ladybug diversity or the role that ladybugs play in keeping plant-feeding insect populations low. We’re asking you to join us in finding out where all the ladybugs have gone so we can try to prevent more native species from becoming so rare.
If you see ladybugs where you live, you might consider participating in their program. If you have kids, this could be a fun family project as well as a wonderful way to introduce them to insects and scientific methodology.
How big can a loveliness get? In June 2019, a group of ladybugs moving through San Diego was so big, it showed up on the National Weather Service’s radar. Meteorologist Joe Dandrea told the Los Angeles Times that the ladybug “bloom” appeared to be about 80 miles by 80 miles, with the insects spread through the sky rather than clustered together.
And finally, a PBS feature about ladybugs for Valentine’s Day in 2016, explaining more about their mating (“ladybug bacchanalia”) and hibernation.
Just goes to show what amazing things are discovered about the natural world when one follows their curiosity. Thanks, Lance, for turning over that boulder all those many years ago.