We have all seen ladybugs and probably have been reciting the rhyme “ladybug, ladybug, fly away home” since we were children. But why are they called this? Presumably half must be male, right?
Actually, not everyone calls them ladybugs. In the United Kingdom, they are called ladybirds, which is even stranger than ladybug, as they are most decidedly not birds. The term lady refers to Mary, the mother of Jesus. In early art, Mary often wore a red cloak – though another tradition robes her in blue – and this beetle reminded people of a red-cloaked Mary. In England, the term bug had a negative connotation, referring to an object of disgust or horror, perhaps even with overtones of sodomy. It is perhaps not surprising then that people used bird rather than bug to describe these beneficial insects. In the United States, the term ladybird morphed into ladybug.
Etymologists prefer the term lady beetle because these insects are beetles, not true bugs. (True bugs, such as aphids, have rigid piercing and sucking mouthparts: Lady beetles have chewing mouthparts.)
Whatever you call them, there are more than 450 species in North America, most often red or orange or yellow with black marks; some are black with red marks. There are other variations, too. Adults are usually round or oval.
The darker the color of these beetles and the more they stand out from their surroundings, the more toxic they are to predators. The deep red is a warning, signaling to predators that they are unsuitable for a meal. Their blood (hemolymph) is toxic to many insect and bird predators. It also smells bad. When threatened, lady beetles defend themselves by releasing this smelly, toxic and bitter fluid from their knee joints – what’s called reflex bleeding. If you have picked up a lady beetle and discovered a yellowish fluid in your palm, the beetle has released its blood into your hand. If you get this bitter fluid in your mouth, it might cause temporary numbness.
Most lady beetles eat aphids. Some also feed on mites, thrips or other small insects and their eggs. Lady beetles overwinter as adults under leaf litter, rocks, bark or other protected places. In spring, they disperse, searching for prey and suitable sites to lay eggs. Some people buy mail-order lady beetles thinking they can use them to control aphid populations on their plants. But these beetles have wings and a habit of dispersing, which makes them unsuitable for this purpose. If you put 1,500 lady beetles in your garden, they will fly away within a couple of days. The aphids in your garden might hardly notice.
Often the ladybugs you buy will be a nonnative species. Whenever you move animals from one are to another, you run the risk of moving pathogens and parasites, too. These can harm the local ladybug population.
Some nurseries and garden catalogs sell lady beetles to control garden pests. People collect these lady beetles in mountainous areas on the West Coast, where the beetles overwinter in large numbers. These migratory beetles have paused their reproductive development (called diapause). If you buy them in the spring, they will tend to migrate north and feed for several weeks before they restart their development and lay eggs. In addition, these beetles sometimes contain parasites that can spread to noninfected beetles if they are shipped to other parts of the country.
Female lady beetles lay eggs (from 20 to 1,000 depending on the species) beginning in spring or early summer. They lay their often orangish eggs near prey – aphids again – in small clusters. Dark-spotted larvae with three pairs of legs hatch from the eggs that some people describe as looking like little alligators, though whoever heard of an alligator with three pairs of legs? The larvae grow and molt three times in about a month, then attaches its hind end to a leaf, head down, where it pupates. The pupal stage lasts about a week, depending on temperature and species. Adults emerge, mate and search for prey. If it is late in the season, they find a good place to overwinter. When they overwinter, they suspend their development.
Lady beetles have voracious appetites, and adults may eat their weight in aphids each day. Females need to eat a great deal so they can produce and lay eggs. Larvae eat even more than females because they are growing rapidly. A seven-spotted lady beetle adult, for example, can eat 100 aphids per day, while a larva may eat 200 to 300. Once an aphid colony has been eaten, the beetles disperse, looking for more food.
Most species of lady beetles are active from late spring to early fall if aphids are available. Only some of the lady beetles in Massachusetts are native – it’s the nonnative seven-spotted ladybug that is the Massachusetts state insect. (Did you even know Massachusetts had a state insect?) Lady beetles migrate south in fall as temperatures cool and north in spring as temperatures warm. They migrate through areas with large numbers of aphids, which means they mostly avoid migrating through urban areas. In summer, there are approximately 90,000 lady beetles in Massachusetts, but by winter that number has decreased to about 22,000 (presumably most of whom are waiting out the winter under bark or leaves).
To encourage lady beetles, follow many of the same gardening practices that you would to encourage bees, such as by having flowers that bloom in each season; lady beetles like shallow flowers, such as alyssum, coriander, dill, milkweed and nasturtiums. Leave the leaves, so ladybugs have a place to overwinter. I know this sound counterintuitive, but leave aphids on plants: The ladybugs will find them eventually. Aphids have coevolved with their host plants and seldom cause serious harm, but once aphids arrive other beneficial insects, spiders and birds arrive to feast on them. These species are in turn eaten by other species, and so on up the food chain.
Seen nearby
Jon Turner spotted this fisher in Bolton on May 7, 2020.
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Jeanine Farley is an educational writer who has lived in the Boston area for more than 30 years. She enjoys taking photos of our urban wild things.
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