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Saturday, May 13, 2023

A Lady by Many Names

 

Lady Beetle Aggregation

Lady beetles, also known as ladybugs or ladybirds, are familiar insects that are part of the Coccinellidae family, which comes from the Latin coccineus meaning ‘scarlet’ and refers to their bright color.  The origin of their common names traces back to a European legend when farmers were said to pray to the Virgin Mary to prevent their crops from being destroyed by agricultural pests.  Commonly red or orange with black spots on their elytra or wing covers, their coloring serves as a warning to predators that they are not good to eat.

Lady beetles have a lifecycle that begins as an egg and hatches into a larva after 4 to 10 days.  The larvae are quite small, generally dark and alligator-like with three pairs of prominent legs.  They typically spend 20 to 30 days eating and growing until they pupate and then emerge as adults. Most lady beetles are active spring and fall, but can be encountered at any time of year.  During the winter, they gather in large groups called aggregations, to mate and protect each other from the cold during their hibernation period, as some can live as adults for more than a year. 

Lady Beetle Larva

There are more than 5,000 species of lady beetles worldwide, with many species imported from other countries.  This practice started in the late 1800s when an Australian species was imported to California for a pest control experiment which helped to triple the orange crop, so efforts were soon put in place to breed them.  Lady beetles typically eat several types of small, soft-bodied insects that are usually described as garden pests, such as aphids, whiteflies, scale insects, mealybugs, and spider mites. In Central Texas, the lady beetle species most commonly encountered are the Seven-spotted (Coccinella septempunctata), Spotless (Cycloneda sanguinea), Convergent (Hippodamia convergens), Ashy Gray (Olla v-nigrum), and Asian (Harmonia axyridis) Lady Beetles. 

Seven-spotted Lady Beetle

With a total of seven black spots on the red elytra and a black head with two white spots, the Seven-spotted is native to Asia and Europe, and was introduced specifically to control aphids.  Having no spots on bright red to orange elytra, and also called the Blood-Red Ladybird Beetle, the Spotless can often be found on milkweed species searching for aphids.  The Convergent has up to six small black spots on its red to orange-red elytra, white lines that converge behind the head, and are often found in aggregations.  The Ashy Gray comes in two color forms; the light form with ashy yellowish-gray elytra and few to numerous black spots, and the dark form with black elytra and two large red to yellow spots.  It feeds on aphids and jumping plant lice.  

Convergent Lady Beetle

Spotless Lady Beetle

The Asian Lady Beetle is highly variable in color and pattern, but typically has a marking that looks like a W or an M behind its head.  This lady beetle is sometimes called the Halloween Beetle, as it often invades homes to overwinter when the weather starts to cool in October.  Native to Asia, it is the most common and widespread lady beetle in North America, and is universally sold in the nursery trade for aphid control.

Asian Lady Beetle