by Alex Robles
The name “Ladybird” has been used for over 500 in England to describe the European beetle Coccinella septempunctata. One of the most popular story of how they got this name is this.
During the middle ages in Europe, swarms of aphids were destroying crops. The farmers prayed to the Virgin Mary for help – and help came in the form of ladybugs that devoured the plant‐destroying pests and saved the crops! The grateful farmers named these insects “Our Lady’s beetles”, which became “Our Lady’s bird”. Since Mary (Our Lady) was often depicted wearing a red cloak in early paintings, and the spots of the seven-spot ladybird (the most common in Europe) were said to symbolise her seven joys and seven sorrows.
They’ve also been called “God’s little cow” or “Moses’s little cow”.
Eventually the “Ladybirds” came to the USA, where the name was americanized to “Ladybugs” even though they’re beetles, not bugs or birds. Now the name “Ladybird/Ladybug” is used to describe over 4,000 different known species of Coccinellidae beetle. Most ladybug species are considered beneficial to our gardens because they eat phytophagous insects (“pests of plants”, sometimes called “plant pests”), but a few of them are considered pests because they do eat and damage plants.
What are they?
Ladybugs are great general predators, meaning they’ll eat many different types of plant pests. The two main kind that we’ll find online or in our local nursery here in the U.S. are: Hippodamia convergens, the convergent lady beetle, a medium sized orange and black species that is commonly sold for biological control of aphids. Coccinella septempunctata, seven spotted lady beetle, sometimes called ‘C-7′, is a medium-sized, orange beetle with seven black spots. It is a European species that was introduced into the US to aid in managing some aphid pests.
- Adult ladybugs will have the characteristic dome or oval shaped bodies. They can range in size from 1mm to over 10mm, depending on the species and on average the females are larger than the males.
- Some adults will come in a variety of bright colors, from yellow, pink, orange, red, or black, and usually have distinct spots that help us identify them.
- These colors act as a warning (aposematic) to predators that might want to eat them, that they’re toxic and distasteful.
- The adults are able to reflex-bleed from the tibio-femoral articulations (leg joints). A yellow smelly alkaloid toxin oozes out of joints which is a defense mechanism against predators. The toxin that the adult ooze out is also present in the immature stages of a ladybugs life (egg, larvae and pupae).
- The main predators of coccinellids are usually birds, but they are also the prey of frogs, wasps, spiders, and dragonflies.
- Females will lay clusters of their elongated eggs close to their prey so the larvae will find prey easily after they hatch.
- The larvae are going to go through four instars (developmental stages between each molt) in 10-14 days before they cocoon themselves. A few days after the adults hatch they’ll be ready to fly, mate and reproduce.
- The total lifespan of some ladybugs in the wild is one to two years on average.
- Ladybugs are a natural predator of pests like aphids, thrips and other sap feeders. A single beetle can eat as many as 5,000 aphid in its lifetime.
- Both the adults and the larvae find and devour aphids, but the adults don’t have a very big appetite. The true predators are the alligator like larvae that will crawl along the surface and chomp most pests it finds. The larvae are usually black with bright spots and spiny.
- When prey becomes scarce, ladybugs (adults and larvae) have been know to supplement their diet with other types of food. They’ll eat flower nectar, water and honeydew that’s excreted by sap sucking insects like aphids and whitflies.
- Cannibalism of eggs, larvae and pupae is also common when prey is scarce.
- Remember that ants will tend and defend aphids for their honeydew and will fight off any ladybugs, looking to feed on them.
Note: Many plant species also contain organelles in locations on the plant other than the flower — known as extrafloral nectaries — that makes a nutrient rich secretion. It’s widely believed that most plants actually use the extrafloral nectaries to attract predators and parasites for protection from pests.
There are four ladybird species available from commercial insectaries:
- Cryptolaemus montrouzieri Mealybug destroyer (mealybugs on citrus, ornamentals, and vegetables, and in greenhouses and interiorscapes).
- Delphastus catalinae Whitefly predator (greenhouse, banded-winged, sweetpotato, woolly, azalea, hibiscus, cloudywinged, citrus and rhododendron whiteflies on ornamentals, vegetables, fruit, and citrus, and in greenhouses and interiorscapes).
- Hippodamia convergens Ladybeetle (aphids, scales and thrips, in citrus, ornamentals, fruits and vegetables, and in greenhouses and interiorscapes). Some suppliers do not raise the beetles, but collect overwintering adults from the mountains of eastern California (Sierra Nevada) – there are two problems with this (A) they carry parasites that could infect local ladybug colonies and (B) it’s believed that since they are harvested wild, they could be programmed to fly west at the end of the winter hibernation (which doesn’t do us any good if they all take to flight back to California and leave our gardens).
- Rhyzobius lophanthae (also called Lindorus lophanthae) (hard and soft scales and mealybugs on ornamentals).
Now releasing ladybugs has always been a little tricky because the adults have this strong natural instinct to fly away. Below is a list of things that I’ve learned to do in all my outdoor gardens to make it more attractive them to lay eggs.
- As soon as I get them home from the nursery or in the mail, I’ll refrigerate them. The cooler temperature is going to slow them down. I don’t want them too active when I release them.
- Before I release them I’ll water the garden or target plant so the ladybugs have something to drink. I don’t know how long they’ve been in their package.
- I’ll wait until the sun has gone down and temperature is cooler to release them. The warmer it is, the more active they get, which means the more likely they are to fly away soon after they’re released. I’m hoping their hunger and the cool night air will make them want to crawl around looking for food, instead of flying away.
- I read that spraying their backs with soda pop and water will “glue” their wings shut so they can’t fly. I’ve never tried this so I have no idea how good this works. I’m not even sure when I would spray them. It says that the sprayed-on solution will work for up to a week until it wears off.
I hope this helps you better understand how ladybugs can help our outdoor gardens. I don’t really have any different advice for indoor gardens. I did read that the artificial light spectrum might mess with how they see or identify their prey.
Grow Learn Teach
University of Florida – http://entnemdept.ufl.edu/creatures/beneficial/lady_beetles.htm
University of Kentucky – https://entomology.ca.uky.edu/ef105