Banner year for bugs?
It's still too early to know for sure, but mild winter could lead to larger than normal summer insect populations.
Wed, Feb 08, 2012 at 04:22 PM
BEE ON THE LOOKOUT: The unusually mild winter could lead to an increase in populations of insects such as this native bee. (Photo: Tom Oder)
Where’s winter? The question is being asked across much of the country.
From the Deep South to Chicago and other northern cities, the winter of 2012 has been unusually mild because the jet stream has kept cold temperatures mostly above the U.S.-Canadian border.
The concern of many in the American horticultural community is that more seasonable weather could suddenly show up with a vengeance in the lower 48 states. Then the question might be, ‘Where’s spring?’
The answer in that case could be ‘Nipped in the bud.’
With only five weeks of winter left until spring officially arrives on March 20, it’s too early to draw any conclusions about how the so-far mild winter will affect the leafing out of plants, spring blooms or the insects that pollinate and feed on them.
In fact, we may not know that until April or May, points out Doug Tallamy, professor of entomology and wildlife ecology at the University of Delaware. That’s because if we have a cool, wet spring, a possibility that Tallamy said concerns him more than the mild winter, insect pathogens could develop that might result in heavy losses of such beneficial insects as beetles and butterflies.
But, if the warm weather continues, entomologists and others agree that it could be a banner year for bugs – beneficial pollinators such as honey bees, native bees, flies and moths, annoying insects such as mosquitoes and destructive ones such as termites.
“The biggest impact of continuing unseasonably mild weather on insect populations is that they will get an early start and their populations will get bigger more quickly than is normal,” said Paul Guillebeau, a professor of entomology at the University of Georgia.
“A hundred can become a thousand, which can become 10,000 that can explode to 100,000 very quickly,” he said.
The most common insects he said people are likely to see coming out early if the warm trend continues are box elder bugs. He said these insects like to congregate in warm areas, such as the sunny side of a house. Large numbers of them will make homeowners nervous because they won’t know what they are. It’s possible that some could even get into the house through cracks around windows and doors. But, Guillebeau pointed out, there’s no chance they will establish a colony inside the house because there is nothing there for them to feed on.
Guillebeau also said that continuing mild winter could cause lightning bugs to come out too early and then have large portions of their population wiped out by a cold snap. There’s no danger they could become extinct, he said, but the situation could develop in which Southerners would see far fewer fireflies this summer.
Dennis Judy, president of the Georgia Pest Control Association, said if the ground continues to stay moist and the temperatures mild that he expects insect populations to thrive. In fact, he said he’s already receiving earlier-than-usual calls about yellow jackets and swarms of termites in South Georgia.
Conditions are also right for mosquitoes to have a very good year, Judy said. Fortunately, it’s still too cool for them to be active now. But, he added, “I can assure you the eggs are there waiting.”
The key thing to watch for, Tallamy said, is the plants. That’s where the food web starts.
The danger with the warm temperatures and the possibility of a cold snap is that temperature is one of the two triggers for the sap flow (day length is the other) that leads to bud break in plants, he said. And warmth can bypass day length as the main trigger.
If the warm trend continues and insects such as caterpillars hatch before bud break, there will be nothing for them to feed on. And they need to eat quickly after hatching, Tallamy pointed out.
If migratory birds arrive after insects have died, it will be difficult for the birds to reproduce because so many bird species feed insects to their offspring, he added.
There are a lot if “ifs” this year, Tallamy said, and there will be some winners and losers. “We are in uncharted territory that’s difficult to predict.”
“We will just have to watch Mother Nature,” said Judy, “and be in awe of what she gives us and then be prepared to deal with it.”