Where Have All The Ladybirds Gone?

As a child, I remember being fascinated by ladybirds. They were everywhere with their armour-like wings that formed a shield when folded. I used to be like every other child - I would hold a ladybird delicately on my finger and sing the old rhyme. "Ladybird, ladybird, fly away home. Your house is on fire, your children alone." Then I would blow ever so gently on the little luck bug to speed her on her way home. Now, I rarely see one; but, they still enthrall me.

One of the great mysteries of the insect world right now ranking up there with the loss of winged pollinators in general is what has happened to North America's native ladybug species? About 20 years ago, they started to "fly away" just like the nursery rhyme. There are still ladybugs to be found; but, the chances are they are not native ladybugs. One formerly widespread species, the nine-spotted ladybug, is now virtually extinct in northeast North America.

While ladybirds can still be seen, they are likely to be an invasive species such as the Asian lady beetle. Invasive ladybird beetles now account for two-thirds of all ladybugs in the United States and Canada.

Other countries are faring no better. The UK is suffering a serious invasion of Harlequin ladybugs. These aliens are taking over and pushing out the native species there as well. Many more countries are fighting their own battle with invasive alien ladybird beetles.

A luck bug. Photo courtesy: bumblebee.org

Until the 1980s, the US Department of Agriculture repeatedly tried without success to introduce imported (alien) species of ladybugs to help in control of insect crop pests like aphids, moths, mealybugs and caterpillars. These invasive species did little more than hang on until lately. Now they are flourishing and the native ladybirds are gone. What changed?

It would appear that more of man's meddling is coming to fruition and we are reaping the rewards. John Losey, one of the world's leading experts on ladybugs, believes climate change could be a driving force behind native ladybug declines. He has enlisted the aid of thousands of "citizen scientists" - especially children - in both the USA and Canada to record sightings. Through his website, Lost Ladybug Project, he has collected over 10,000 reports and is still analyzing all the data.

Warmer temperatures may be a godsend for sun worshippers; but, they are a disaster for ladybirds. Warmer weather means less winter snow to cover the ladybugs' overwintering sites. They hibernate in grass, leaves and bark at the base of trees. The snow cover keeps the ground temperatures at a constant 0oC which is cold enough for them to remain dormant all winter without freezing to death.

Constant temperatures are the key to the little beetles successful hibernation. If the temperature drops too low, they freeze to death; and, if there is a warm spell, they could wake up, fly off leading to an early demise if the temperatures drop again.

John Losey says: "Overwintering mortality could be an important factor" in the declines.

Ladybugs are the workhorses of the pest suppression species. They eat many times their weight in aphids and other plant-eating pests. Photo courtesy: gardenerstips.co.uk

The new introduced species have a unique overwintering habit that allows them to flourish regardless of the climate. In the wild, they use the cracks and fissures in cliffs for overwintering; but, in developed areas they find gaps and holes in the walls of houses and buildings. When the weather turns colder, they all mass there together in the chinks they have found or behind a bit of loose siding or anywhere that affords them a little protection for the weather.

However, one of the unforeseen consequences of importing the Asian ladybug is this habit of invading homes in swarms making it a nuisance. They have been nicknamed the "Halloween ladybug" because of the time of year they seek shelter inside. Invasive ladybugs are capable of biting though it is not dreadfully painful. However, when frightened they give off a yellowish ooze that can stain wall and smells bad. What an endearing quality!

To get an idea how beneficial these little guys can be in the plant-eating pest eradication department, read on. Ladybugs and other predator insects are so effective and so voracious, they add $4.5 billion to the US economy each year through natural pest suppression.

Additionally, there are hidden financial and environmental benefits that are not reflected in the $4.5 billion. For every acre that is treated by use of natural pest suppression, no chemicals are bought and used. Not only does the farmer save the price of the chemicals, there is no damage to the environment in that area.

There is another theory put forward by Scott Black, executive director of the Portland, Oregon-based Xerces Society for Invertebrate Conservation. He feels the problem may be that native ladybirds are specialists while the invasive species are generalists. The native species have been here so long they have specific food, temperature, foliage; and, other requirements. If they are unable to find these conditions, they die rather than adapt.

The alien species; however, are generalists able to adapt to many changing conditions. If the conditions change, they change too. One theory is that introduced species like the Asian ladybug have pushed the native species out of their favoured habitat; and, the native species being unable to adapt are dying.

Another idea is that the number of parasitic wasps that prey upon ladybugs increased with the introduction of alien ladybugs. Changes in cropping patterns and loss of agricultural land also may have played a prominent role.

Volunteers: Jaya Walsh and her son Gaelen look for ladybugs as part of the Lost Ladybug Project near Ithica, N.Y. Photo courtesy: Christian Science Monitor

The truly worrisome aspect is the impact of the invasive species on the native species; not to mention, the wider ecosystem. It turns out that the imported ladybugs are highly aggressive predators that may be able to eradicate our own species. One of the most critical dangers of reduced ladybird diversity is that if there is a disease outbreak, there are fewer species to fall back on. We could lose ladybugs altogether; and, we cannot afford to lose even one species of winged pollinator.

John Losey says it very succinctly: "If you get a disease that wipes them out, you don't have a backup."

EnviroFunFact

A Luck Bug. Photo courtesy: flickr

Ladybugs are probably the world's most beloved insect - the official bug of six US states and thought to in some cultures to be close to God or saints. The Turks associate them with good fortune and call them the "luck bug". They're also one of nature's workhorses.

Voracious hunters of aphids and other plant-eating pests that damage crops, ladybugs and other predator insects add $4.5 billion to the US economy each year through natural pest suppression, according to a study co-authored by entomologist John Losey in 2006.

The Lost Ladybug Project

Photo courtesy: Cause2

When I first moved into my condo 15 years ago, I thought I lived in a ladybug flight path. They were all over the balcony, they flew in the windows, they were everywhere. I loved it!! I have always loved ladybugs - it's been a lifelong love affair.

Unfortunately, my ladybugs do not visit me as much anymore. Actually, they are few and far between nowadays. They have gone the way of the frog, the grasshopper, the garden snake and many other disappearing species I remember from childhood.

The Lost Ladybug Project is tracking ladybugs throughout the US and Canada in an effort to gain added insight into their disappearance. Great family activity to do with the children; and, the website has content designed especially for children.

This from Cause2:

Scientists are asking children, adults, families, educators and everyone from two to 102-years-old to join a citizens-science group to help our ladybugs.

Ladybugs were once one of the most common bugs found across the U.S. and Canada. Controlling pests that attack farm harvests, balancing the ecosystems in forests and fields, their industriousness is an important part of the ecosystem.

During the past two decades as invasive look-alike ladybugs expanded their territories and pollution and habitat loss have crowded them out, species of Native ladybugs began vanishing and the invasive species began increasing. These include the multicolored Asian ladybug, checkerboard ladybug and the seven-spotted ladybug.

The larger, rounder multicolored Asian ladybug had been introduced as a biological control for scale bugs then mass produced across the lands. It even eats ladybug larvae. The checkerboard ladybug, which is small and yellow, hitched a ride from Europe through the St. Lawrence River in the 1960s and has since been traveling steadily southward. The seven-spotted ladybug, also from Europe, came to North America in 1956. Its population extended its range as the Native nine-spotted and two-spotted began disappearing.

“This has happened very quickly and we don't know how this shift happened, what impact it will have, and how we can prevent more native species from becoming so rare,” said John E. Losey, Cornell University entomologist.

In June 2007 the Lost Ladybug collaborators, headed by Losey, received a $2 million grant from the National Science Foundation to expand the program throughout New York and extend it nationally. Their goal is to use citizen science to bring more participation in the search for the bugs. The ladybugs are collected into vials with twigs and drops of water. The date, time and place they were found are written down. The discoveries are placed on a gray square and their pictures are taken. Digital images are sent to the project's website, or color prints can be mailed to the university. The ladybugs are returned to where they were found.

The database will help scientists understand the shifting changes on earth, help farmers with crops and further understanding of rare species and the ecosystems in which they live. There are more than 5,000 species of ladybugs around the earth. About 450 are Native to North America. It’s not yet known if the new species inhabiting the continent will serve the same function or favor the same habitats as the native species.

In turn, youth will learn about the place of the ladybug in the community of nature and the importance of biodiversity and conservation for the web of life through hands-on participation in research. Educational materials, books, collection vials and nets are provided through Cornell University.

The project's website will post instructions for finding collection sites, making nets, photographing ladybugs, submitting data and uploading photos. The website will also offer an automated identification feature to provide people with real-time feedback on species that have been collected. Ladybug lore, myths, songs and culturally based stories are being posted to explain the relationships between ladybugs, pests and our food.

As of this year, more than 3,000 ladybugs will be in the new data display sent in by hundreds of participants across the U.S. and Canada.

For more information visit the Lost Ladybug Project.