Insects: Ladybug

Range: almost worldwide but especially in temperate climates Habitat: gardens, forests, weed patches, and vacant lots full of weeds

One cute insect

One of the most popular symbols of springtime is the speckled, miniature dome of a ladybug strolling along a plant stem looking for its next meal. They are also found in nursery rhymes and folklore around the world. Of all the "creepy crawlies," ladybugs are the most beloved and respected of insects.

Lady "bugs" are a group of beetles that are also known as ladybird beetles, or lady beetles. In fact, the name ladybug is scientifically considered to be a slang term for the more correct name, lady beetle. They are harmless to humans and are often considered cute by people that don't like other insects. They are small and usually quite round in shape. The color on the wing covers (elytra) can be yellow, orange, or red and often has small black dots on it. Some species are entirely black. Ladybugs also have black legs, head, and antennae. Some people think ladybugs are a sign of good luck.

Lady beetle bodies

Like other insects, the ladybug has an exoskeleton made of a protein like the one that forms our hair and fingernails, and their bodies are made up of three parts: the head, thorax, and abdomen. Each of the three body parts has a different function. The head houses the ladybug’s mouthparts, compound eyes, and antennae. The thorax is where the three pairs of legs and two pairs of wings are attached. The first pair of wings is the hardened elytra that protect the flight wings underneath. When the ladybug takes flight, the elytra open and the thin, veined wings unfold. The abdomen contains organs for digestion, respiration, and reproduction. Adult ladybugs breathe air like humans, but the air enters the body through openings called spiracles, found on the sides of the abdomen and thorax.

Many phases of the ladybug

The female ladybug will lay her tiny, golden eggs on the undersides of leaves, usually near an aphid colony. In most species the eggs will hatch into larvae (that look like caterpillars) in just a few days. Once hatched, the larvae eat about 350 to 400 aphids in the 2 weeks it takes them to become fully grown. As they grow, the larvae shed their skin several times. Once they are a certain size the larvae will stop eating and will attach themselves to a plant leaf or stem. They will then enter their next developmental stage, called the pupa. When it is time, the adult ladybug emerges from the pupa. Though it now has all the features of an adult beetle, its exoskeleton is still very soft and light in color.  The emergent insect is referred to as "teneral" during this stage, and it will take several hours for the exoskeleton to harden and darken. Their entire life cycle only takes three to seven weeks.

Red, black, and not very tasty

Many ladybugs are brightly colored to advertise to predators that they are not worth the effort! If disturbed, they can release a foul-smelling chemical from their "knees" to keep enemies away. Predators link the color combinations of bright oranges, reds, and blacks with these unappetizing chemicals and they avoid eating the ladybugs. This advertisement is so successful that even ladybugs that are not distasteful mimic the colors of the poisonous ones.

Down time for busy beetles

It is thought that ladybugs gather together in large groups to diapause (the insect equivalent of hibernation). This helps the beetles conserve resources and brings males and females together for reproductive purposes. Some of them will gather in protected hiding places such as logs, buildings, ground cover, beneath snow drifts, and even in houses! Millions gather in the southwestern United States, where they cover the ground like a blanket of red and black. Ladybugs can survive for up to nine months by living off their stored reserves. They break out of diapause when the temperature reaches 55 degrees Fahrenheit (13 degrees Celsius), which is generally when food becomes available again.

Helpful hungry insects

There is nothing ladylike about a ladybug's appetite: an adult may eat up to 75 aphids per day! They also eat other harmful insects like fruit flies, thrips, mites, and other plant-sucking insects. Although not all ladybugs are carnivorous, the predatory ones are very helpful to gardeners because they do not damage crops while filling their bellies. In fact, they provide pest removal services that many growers use instead of pesticides. For this reason, ladybugs can be purchased from many suppliers. More than 100 species of ladybugs are now living in California because of the benefits they provide. Most of the time this is a good thing, but now and then introduced species displace our California natives. We must remember: all things in moderation!

Ladybug lore

Worldwide, ladybugs are seen as omens of good luck. In England, finding a ladybug means there will be a good harvest. In Sweden, if a ladybug lands on a young maiden's hand, she will soon be getting married. In the United States, ladybugs are the official state insect of Delaware, Massachusetts, New Hampshire, Ohio, and Tennessee. How interesting that such a tiny insect can make such a vast difference in the world!