Bug of the Day: Ladybug
In England they have been called ladybirds for over 600 years, but in the United States we call them ladybugs. The name is a misnomer, though – these insects are not bugs at all, but are actually beetles (and they are not all ladies.) They can be very useful to people because the larvae and adults of many species are voracious predators that eat soft-bodied pests, notably aphids.
Originally, the common name “ladybird” referred to one species of European beetle, Coccinella septempunctata, commonly known as the “seven-spot ladybird.” Over time, the name “ladybird” was applied to other beetles in the family Coccinellidae, which includes almost 6,000 different species worldwide.
In Florida, we have at least 105 species of beetles from the Coccinellidae family; some are native, others were introduced deliberately to control pests, or they arrived here by other means. The most common species in North America, Harmonia axyridis, the harlequin ladybug, was first introduced in 1916, making this year its 100th anniversary in America.
Ladybugs are hemispherical in shape – like a ball cut in half. Though we typically think of them as being bright red in color with black spots, there is wide variation in the physical appearance in this family. Some ladybugs have seven black spots, or more, or fewer. They can have stripes or no markings at all. Their colors can range from yellow to orange to red while some species are black, gray, or brown.
Most beetles in the family Coccinellidae are predatory, and feed on soft-bodied insects and mites. Some predatory species are generalist predators, eating anything they can catch, others are very prey-specific and only consume insects from one species or a closely related group of species. Predatory ladybugs are used as biological control agents to help farmers fight crop damage by aphids, scale insects, mites, whiteflies, mealybugs, and psyllids. There are also species of ladybugs that eat plants, and a few of them are considered crop pests.
Some farmers make use of the predatory ladybugs already present in their area and support local populations by avoiding the use of chemicals that might harm them. Sometimes, farmers release additional ladybugs into an area where they want enhanced pest control; they usually release larvae, which cannot fly away (unlike adults) and will remain in the area where they were released.
Because ladybugs hibernate, people sometimes find them indoors during the fall as the beetles seek a cozy place to spend the winter. Although it’s unusual, occasionally a large aggregation of ladybugs will be found hibernating in a home or business, a situation that can create problems for human occupants due to allergy issues, beetle waste, and the likelihood of smashed ladybugs everywhere if hundreds or thousands of them enter a space used by people.
As a matter of fact, even a close encounter with one ladybug can be unpleasant. Many species employ a defense mechanism known as reflex bleeding, in which a distressed ladybug releases a dark fluid called hemolymph, the insect equivalent of blood. Hemolymph smells bad, tastes bad, will cause numbness to the mouth, and will stain some fabrics and surfaces.
(One Bug Week staffer learned the hard way about the “tastes bad” and “causes numbness” consequences, after a ladybug accidentally landed in a plate of soupy Chinese food he was eating – he removed the beetle, took another bite, and soon realized his mistake. He should have discarded the food the beetle contacted, and then possibly discarded the spoon for good measure. Don’t worry we cannot find any account of people being killed by a little ladybug hemolymph.)
Possibly because they benefit farmers, ladybugs are considered a symbol of good luck in many cultures. In Italy, if you see a ladybug, you are supposed to make a wish. So, if you’re out and about and spot one of these amazing insects – quick! – make a wish and thank them for devouring our pests.
But think twice before picking them up.
You can read more about ladybugs in this “Featured Creatures” document from the UF/IFAS Entomology and Nematology Department.
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UF/IFAS Photo by Tyler Jones