Told my mother-in-law I was thinking of buying ladybugs for my garden because of an interesting article I’d read. She had a small conniption fit about the ladybugs that infest her home in the fall and bite her.
I researched this. Ladybugs’ mouths are too small to actually bite a human. They don’t have teeth. The yellow-orange Asian ladybugs have external pincers to draw water into their mouths and/or investigate surfaces which may feel like a sharp pinch. Typically the Asian type will occasionally “bite” if you are sweaty or are strongly perfumed. Native ladybugs don’t even do that.
Yes, ladybugs seek warm places to hibernate in the fall, which may include your home. They typically like older homes because of the heat they reflect. As they settle in for the season they release pheromones, which let other ladybugs know they’ve found a good place to settle in together for the cold winter. The best defense is seal your home well and scrub areas where they’ve congregated in the past with soapy water to remove the pheromones.
I want to attract ladybugs to my garden because – besides being cute – they will allow me to cut back on pesticides and rid flower beds of aphids and other insect pests. Aphids are the most common garden pest and are difficult to control by spraying. One ladybug can eat dozens of aphids a day, seeking them out wherever they hide. In fact a ladybug can eat as many as 5,000 aphids during its lifespan. Ladybugs also prey on mealybugs, scale, leaf hoppers and mites. They are one of the most active predators, searching from dawn to dusk for food.
My research turned up all sorts of info, which I’ll share in a series of articles… in case you too might be interested in cutting back on the pesticides in favor of cute little beetles.
Ladybugs have a very characteristic convex, hemispherical to oval body shape. The head is covered by a hood called the pronotum. Their antennae are 11-segmented and inserted at the inner margin of the eyes below the front. What is really cool is ladybugs can retract their heads like a turtle into the prothorax. They may be white, yellow, pink, orange, red or black, and usually have spots. Like many of other brightly-colored insects, ladybugs are bad-tasting to predators. When disturbed they may secrete an odorous, distasteful fluid out of their joints to discourage enemies. There are about 4,000 species found worldwide and more than 350 in North America. [guide to ID ladybugs]
Adult females lay their clusters of eggs in the vicinity of aphid, scale or mealybug colonies. The larvae eggs are highly nutritious and rich in protein. A ladybug will lay a large number of both fertilized and unfertilized eggs, because the unfertilized eggs are a primary source of food for the larvae.
The larvae of ladybugs resemble small crocodiles and are just as predatory. They are spiny and black with bright spots, a small pointed stomach and their legs protrude from the side of their bodies. During the one month ladybugs are larvae, they can consume hundreds of aphids or other soft-bodied insects. Although they look dangerous, ladybug larvae are harmless to humans. After feeding on insect prey for several weeks, the larva pupates on leaves.
Within a year, there can be as many as 5-6 generations of ladybugs as the average time from egg to adult is about 3-4 weeks. In the spring, females lay from 50-300 eggs. The eggs take 3-5 days to hatch and the larvae voraciously feed on aphids for 2-3 weeks before they pupate into adults.
Adults spend the winter in protected hiding places such as plant refuse, crevices in logs, buildings, and particularly like under fallen leaves. They need areas protected from frigid winter temperatures. They hibernate in mass with several hundred adults gathering at the base of a tree, along a fence row or under a rock… or in my mother-in-law’s house.
With the onset of spring the adults leave their winter clusters and fly to fields and yards. When the adults emerge they feed on aphids, but as fall approaches they also eat pollen which supplies fat for winter hibernation. Adults tend to move on once pests get scarce, while the larvae remain and search for more prey. Pollen in the diet is also necessary for egg laying.