News

Ladybugs, Where Do They Go?

11/2/2020

The gardens around Crab Cove are abuzz with insects in summer, including ladybugs. They are a gardener’s best friend and an important part of the environment. Over their lifetime of about one year, ladybugs can eat up to 5,000 aphids and other soft-bodied creatures that consume plants. In the warmer months, watch for these attractive beetles around your home and in undeveloped areas as they search for food. Their larvae, who look like tiny alligators, have just as big an appetite for the same prey. But what happens in the colder months when aphids disappear?

Sometime in early to mid-fall, ladybugs from the Bay Area lowlands seem to fly away with the prevailing winds to the east, settling down in numerous places in the East Bay hills to hibernate. In Reinhardt Redwood Regional Park near the junction of the Stream and Prince Trails, thousands of convergent ladybugs (Hippodamia convergens) can often be found huddling together from about late October to mid-February. They are on objects like bushes, logs, fence posts, and underneath leaves. It is an amazing sight to behold that often brings joy to both kids and adults.

Why do convergent ladybugs come together in such numbers? Possible reasons include:
• Staying moist and saving energy by hibernating in a cool, damp, and safe location. Cold locations also protect against bacterial and fungal infections.
• Easily finding mates during warmer periods, especially just before they fly away in February (observe carefully).
• Protection in numbers — perhaps they are less likely to be eaten when together. Their red color warns predators that they taste yucky,

The hibernating ladybugs have never spent a winter here, so how did they find the same place as previous
generations? Perhaps it’s instinctual to fly east, and winds may tend to steer them towards certain areas. Pheromones, or scent markers left behind on the ground and possibly in the air, may have attracted them to specific locations.

Ladybug Fun Facts
• There are about 175 species of ladybugs in California, 5,000 in the world, and they come in many colors.
• Ladybugs can beat their wings about 85 times per second.
• When disturbed, they can emit a toxic, yellow liquid out of their leg joints.
• Ladybugs are actually beetles, not true bugs. If you want to visit the hibernating beetles, it is a 1.5-mile fairly easy walk one way, up the Stream Trail when starting at the Canyon Meadow Staging Area in Redwood Reinhardt Regional Park.

Please respect them by watching from a short distance. Collecting is prohibited, plus they would not survive if taken. For a healthy habitat and to help protect animals like ladybugs, please keep your garden free of pesticides, and consider buying organic food.

For more about ladybugs, enjoy KQED's Deep Look documentary which was partially filmed at Reinhardt Redwood Regional Park.

Ladybug larvae and convergent ladybugs in Reinhardt Redwood Regional Park.


Jennifer Vanya, Public Information Specialist
510-544-2207

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