The Ladybug’s Life Cycle
Most people, including gardeners, do not recognize the adult ladybug.
It’s easy to understand — the immature forms of ladybugs don’t look like their adult counterparts — but it is important to learn about ladybugs at all stages of their life cycle to ensure that beneficiaries aren’t mistaken for pests. While ladybugs are known to eat aphids in their adult form, the larvae of ladybugs eat hundreds more aphids than adults before they pupate.
It is important to note that ladybugs, which entomologists call “ladybeetles”, are not insects at all. Ladybugs belong to the Coleoptera order, which is the same order as all beetles. Bugs, on the other hand, are members of Hemiptera. A beetle undergoes a complete transformation between its larval stage and its adult stage (also known as imago), while a true bug immature is called a Nymph and already looks like its adult form.
Ladybugs can be any colour combination, but the most common is red with black spots. This includes the North American Nine-spotted Ladybug (Coccinella Novemnotata), and the European native Seven-spotted Ladybug (Coccinella Septempunctata). The ladybugs can come in a variety of colours, including yellow, orange and gray with stripes or spots. Harmonia axyridis, the multicolored Asian ladybeetle has such a wide range of colors and spots that it is known as harlequin. This means “in various colours.”
The seven-spotted ladybird as well as the multicolored Asian Lady Beetle were introduced into the United States to control pests. They are effective in reducing aphids, but they also pose an environmental problem as they compete with native North American ladybugs. All three species look similar in their larval stage, making it difficult to eradicate them.
Not all ladybug species are carnivorous. In the Coccinellidae family of ladybugs, there is also the subfamily Epilachninae. These are the plant-eating Ladybugs. The squash ladybug (Epilachna bearalis), also known as the squash beetle in the garden, attacks vines, leaves, and rinds of cucumbers, pumpkins and melons. On the other hand, Mexican bean beetles (Epilachna varivestis) feed on legumes. Gardeners can rejoice that these pests are not mistaken for ladybugs in their larval stages, when they have long black spikes and are yellow.
Here’s everything gardeners should know about the life cycle of this insect, whether you call it ladybugs, Ladybirds (the preferred term in the U.K.), or Lady Beetles.
Adults
The first time a ladybug can fly is when it emerges as an adult from its pupa. It takes some minutes for it to adjust to its new shape and spread its wings. The newly-minted adult ladybug will have a yellowish exoskeleton, which hardens to become the permanent color of the ladybug. Adults can survive for up to one year by overwintering somewhere out of the weather.
Pupa
A larva that is about to pupate will cling to a leaf. As it starts to take on the form of an adult ladybug, its black skin molts. It changes from black with orange dots to yellow or black with red spots over a period of one to two week.
Larva
The larvae of beneficial ladybugs look like small black alligators, with stripes or spots in orange. The larvae have six black feet and are so tiny that it is easy to miss. They will rapidly advance through the four instars if they eat a constant diet of scales, mites and aphids. After a period of three to one month, the pupae are ready.
Eggs
The eggs are grouped in clusters ranging from 5 to 30 on the underside a leaf, near food sources such as an aphid nest. The eggs are oval, yellow or orange and stand up on end.
If you have an oleander infestation, you may see ladybug eggs on the milkweed. The larvae begin to eat the aphids when the eggs hatch within two to ten days.
