Saturday, March 20, 2010

Ladybug Luck

Oh happy day! The sun has been shining down on New Haven since mid-week. On Thursday the temperature got to the mid-sixties, and actually felt like the mid-sixties for the first time in months. It was warm enough to stroll up the street for an outdoor lunch at Nica’s Market. So many people had the same idea that we had to wait for a table. Orange Street had come alive. It was so bright and balmy, so Springlike, so strange to see the trees still bare. But so nice to be sitting outside. (It’s been a very gray, wet winter in The Have.)

Just before we arrived home, the first ladybug of the season lit on my left shoulder, and we both instantly smiled at my good fortune. In the split second I had to admire her before she flew away, all I managed to note was that she was orange-red with at least two black spots. And then I paused to consider what makes ladybugs so lucky. It should come as no surprise that I have lots of information to share with you.

The ladybug is actually a beetle (Coleoptera) in the family (Coccinellidae). There are thought to be more than 5,000 different species of ladybird in the world, with more than 450 species found in North America alone. This beetle is universally regarded as a symbol of good luck. In Christian cultures, the ladybug has strong associations with the Virgin Mary.

Why does every culture associate this little red creature with good fortune? It is most likely because the ladybug is one of the most effective forms of pest control. I looked up “ladybug” in my 1978 edition of The Encyclopedia of Organic Gardening, published by Rodale. The entry reads: “The familiar ladybug is probably the best-known beneficial insect in the garden. Both the cherry-colored adults and lizard-like larvae are important in making poison-free gardening as easy as it is. Larvae have the best appetites, consuming aphids, asparagus beetle eggs, Colorado potato beetles, grape rootworm, bean thrips, alfalfa weevils, and cinch bugs. The beetles specialize on aphids, scale, mealybugs, whiteflies, and spider mites.” They have few predators, since, for their protection, they exude a yellow, sticky substance with a repulsive taste.

John M. Samaha, SM, a brother at the University of Dayton, wrote extensively on the the Marian roots of the name “Our Lady’s Bird.”  He also spoke in great depth about the first use of ladybugs as pest control in the US. In the 1890s, the  orange groves in California’s Santa Clara Valley were being decimated by a previously unknown pest — the aphid, which had arrived on flowering peach trees imported from China. The aphids had a field day in the groves and soon spread all the way to the East Coast. The Department of Agriculture tried a variety of pesticides, with little success. The visionary Mr. C.V. Riley, chief entomologist of the Department of Agriculture, suggested introducing other insects which would prey on the aphids. When he learned that the ladybird beetle was keeping aphids under control in Australia, he had some sent to California. When set free in an infested orange grove on trees covered with gauze screens, the ladybugs cleared the trees of pests within a few days. More ladybirds were imported, and California scientists began to raise them in wholesale quantities.

Ever since then, they have commonly been used as pest control, both to combat large-scale infestations of crops, and to wipe out aphids in home rose gardens. But, as with most actions, there have been unintended consequences.

All ladybugs devour insects, but some species proved more aggressive than others in their eating habits. The USDA turned once again to foreign imports. One of these was the multicolored Asian lady beetle (Harmonia axyridis), which was imported and released as early as 1916. Over the years, federal, state, and private entomologists released the insect at a number of locations, but this species did not take hold and spread until the 1990s. It is now found on both coasts and throughout most of the US. Some scientists believe that current infestations originated not from intentional releases, but from beetles accidentally transported into New Orleans on a freighter from Japan. Harmonia axyridis has achieved notoriety for autumnal home invasions in which swarms of ladybugs enter homes through unprotected openings to escape the cold, all the while attracting others with their pheromones. And remember that protective substance they release when threatened? While nontoxic, it apparently stinks and leaves yellow stains. Scientists in Mississippi have found that catnip oil is useful as a repellant.

Even worse still, not only are these Asian lady beetles home invaders, they have been found to prey on native species! 

In fact, today most species of ladybugs native to North America can now only be found at the base of the Rockies and further west. I had no idea just how lucky I was to have that ladybug land on me. While I don’t believe “my ladybug” had enough spots to be Harmonia axyridis, I can not identify her. Although she may have been the seven-spot, which is also non-native, I like to think she was one of the rare ones, but now I'll never know.

In 2008, after being unable to find a single specimen of the nine-spotted ladybug (the New York state official insect) for 16 years, scientists at Cornell started The Lost Ladybug Project, funded with $2 million from the National Science Foundation. The project is intended to help scientists better understand why some species of ladybugs have become extremely rare while other species have greatly increased both their numbers and range.

The project has enlisted the help of citizen scientists, in particular schoolchildren, around the country, asking them to locate and photograph any ladybugs they can find and to upload the photo and geographic location to the project website—a hands-on science project.

At Cornell, South Dakota State University, and the nearby North Central Agricultural Research Laboratory, scientists are breeding colonies of nine-spotted specimens captured in the grasslands of South Dakota, where the species is also now becoming rare.  Researcher John Losey said, “Specifically, we’re testing if the introduced species could have introduced a disease, outcompeted the natives for aphids or interbred with the native species… Once we know why they declined, we will be on our way to being able to help them and other species in the same predicament. All this research was made possible by our dedicated volunteer ‘spotters.’”

After losing a colony of nine-spotted ladybugs in 2008 and nearly losing another in 2009, researchers in South Dakota recently discovered that the colony could thrive if their diet included varieties of aphids that have been around since the early 1900s. This could be a breakthrough in understanding nine-spotted ladybug decline.

The Lost Ladybug Project is a perfect teaching tool for the classroom or a youth group. The site has all the materials you need, including instructions for a sweep net to help you collect specimens for study without harming them. You can go online to see the most recent map with confirmed sitings. While most of the rare varieties have been recorded in the western US, there have been two recent sitings of the two-spotted variety in Massachusetts. Everyone, young and older, is welcome to submit photos. So keep your digital camera handy and your eyes wide open so you can help the Cornell scientists solve this mystery. There have been 4728 ladybug photos contributed as of March 20, 2010.

What more can you do?  Learn to identify ladybug larvae so you don’t accidentally kill them thinking they are problem pests. And try attracting ladybugs to your garden by planting  plants with pollen or nectar, such as dill, calendula, Queen Anne’s lace, fennel or cock’s comb.

Even if you do not believe in the luck of the ladybug, I hope you have a newfound respect for this valuable and endangered creature, and that you will never, ever harm one, in either its larval or its adult state.

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