Over the past 20 years, the ladybug distribution in North America has been changing. Native ladybugs that were once very common have become rare while non-native ladybugs have increased in number and range.
According to The Lost Ladybug Project, scientists aren't sure why this is happening or how it will impact the role that ladybugs play in keeping plant feeding insect populations low.
In an article of Cornandsoybeandigest.com published in 2011, Cornell University Extension Entomologist John Losey said that "The total number of ladybugs may not have declined." Perhaps they were crowded out of their traditional habitat by more competitive invaders, although native numbers had started to shrink before the foreigners took over.
Seven-spotted ladybugs, for instance, were introduced intentionally to feed on pea aphids. Likewise, multicolored Asian ladybugs were brought to this country to help control pecan aphids in the Southeastern U.S. Both types have become major predators of soybean aphids.
Getting ladybugs to come to your garden, and more importantly stay in your garden, is easy once you know a few simple facts and tricks. Check out some tips on how to attract ladybugs to your garden at Gardeningknowhow.com.