Ladybugs

Known as ladybugs, lady beetles, or ladybirds (Brit.), these voracious feeders are a welcome site in any garden.

Adult lady beetle (Gilles San Martin) CC BY-SA 2.0

​Members of the Coccinellidae (Co-see-nell-e-day) family, they are not true bugs at all. True bugs have piercing and sucking mouthparts, wings that are membranous or hardened only at the base, and they are born as miniature adults. Lady beetles (the correct name) have grasping jaws, a hard shell, and they go through distinct developmental stages. The ladybug of your childhood is actually a beetle.


Lady beetle development

Lady beetles go through four distinct stages of development called instars. Each of these instars look very different. This is called complete metamorphosis.

    Egg - Females lay as many as 300 eggs, in spring and summer, right in the middle of an aphid infestation.
   Larvae - Two to five days after eggs are laid, larvae that look like tiny alligators emerge. The larvae devour nearby aphids for the next three weeks. 
    Pupae - Once it has eaten its fill, the larvae develops a hard shell and it rests as a pupae for a week or so.
    Adult - A black adult beetle emerges from the pupae and returns to feeding on aphids, as well as hard and soft scale. Over time, different colors and spot arrangements* emerge. They can live 2 -3 years. Lady beetles hibernate in winter, living off of fat stores, much the way a bear does! And in spring, there can be massive migration flights, called ‘blooms’ that can be several miles wide and long.

Lady beetle larva (Jo Re) Pixabay

*The number of spots on the insect's back does not indicate its age. Coloration and spot arrangement are determined by species and genetics.


Lady beetle diet
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Over the course of its life, a single lady beetle may eat 5,000 aphids. They also eat alfalfa weevils, asparagus beetle larvae, bean thrips, chinch bugs, Colorado potato beetle larvae, grape rootworms, mealybugs, mites, scale insects, spider mites, and whiteflies.


Being voracious feeders, lady beetles also eat lacewing larvae and other soft-bodied beneficials. They will even eat other lady beetles. There are also vegetarian lady beetle species which feed on mildew, fungi, or plants.


​To buy or not to buy

Many novice gardeners buy lady beetles, but this is unnecessary. If a garden has aphids, lady beetles will find them. You can attract lady beetles by planting brightly colored flowers and other insectary plants that provide food, shelter, and landing zones for lady beetles and other beneficials. Also, avoid using broad spectrum chemical pesticides.


Lady beetle anatomy

Lady beetles have a protective exoskeleton made out of a protein much like our hair and fingernails. They have 3 main body parts: head, thorax, and abdomen.

    Head

• grasping jaws that chew side-to-side
• compound eyes
• antennae - used to touch, taste and smell
• pronotum - many people mistake the pronotum for the head; a lady beetle can pull its head into the pronotum the way a turtle pulls into its shell

    
    Thorax - strong muscles that control the legs and wings

• legs - 3 pair of legs with special organs on their feet used to smell things 
• wings - two pair of wings
• functional wings beat 85 times a second to fly 
• elytra - hard shell made from modified wings; used to protect the functional wings

    
  Abdomen - contains organs for digestion, reproduction and respiration [Adult lady beetles breathe air through body openings, called spiracles, on the sides of the abdomen and thorax.]


Lady beetle species

There are more than 4,500 species of lady beetle worldwide, with nearly 200 species in California. These include:

• ashy grey lady beetle
• Asian lady beetle
• black lady beetle
• California lady beetle
• eleven-spotted lady beetle
• mealybug destroyer lady beetle
• nine-spotted lady beetle
• seven-spotted lady beetle
• twenty-spotted lady beetle
• twice-stabbed lady beetle
• vedalia lady beetle

Bad lookalikes

Most lady beetles are beneficial insects. The Mexican bean beetle is a close cousin and it destroys many bean crops. Mexican bean beetles are orange with 8 black spots and they interfere with photosynthesis by turning leaves into lacework. Also, introduction of the Asian Harlequin variety of lady beetle (Harmonia axyridis) has been devastating to native populations.


Like skunks and the Monarch butterfly, the familiar bright coloration is a warning to predators. Lady beetles can secrete an alkaloid toxin from the joints in their legs which tastes awful. This behavior is called “reflex bleeding”.


Did you know that a threatened lady beetle may also play dead to protect itself? I didn't either.