WOOSTER, Ohio - Ohio State University entomologists are trying to find out what makes the multicolored Asian lady beetle tick.
If successful, the information could provide relief for Ohio homeowners who must contend with the insect, which invades homes during the fall seeking a warm, dry place to over-winter.
"We've gotten information from people saying that they get thousands upon thousands of lady beetles in their homes every year, and they say it just gets worse year after year," said Joe Kovach, of the OSU integrated pest management program. "I think the number of lady beetles just keeps growing exponentially. They aren't going to go away any time soon."
With the thought of effective management practices in mind, the researchers surveyed 1,500 homeowners throughout Ohio seeking information on their experiences with the multicolored Asian lady beetle. Preliminary data from the respondents is helping the researchers learn more about the insect.
The OSU IPM program has scheduled town meetings, beginning Sept. 6, in four counties (Tuscarawas, Athens, Pike and Franklin) that have been most affected by multicolored Asian lady beetle infestations. The town meetings are designed to present what is known about the biology and ecology of the insect, the results from the Ohio Lady Beetle Survey, and suggested management techniques that will be used in a research project sponsored by the IPM program.
The multicolored Asian lady beetle, introduced to the United States from Asia, is considered a beneficial insect in that it eats other insect pests, like scales and aphids, that damage ornamental plants and crops. The insect, however, is quickly becoming a nuisance for homeowners who spend the fall months trying to rid the lady beetle from their homes using a variety of techniques from applying pesticides to vacuuming three or four times a day.
"The Asian lady beetle makes a good bio-control agent, but I don't think most people realized how much the insects like to use homes as an over-wintering site," said Kovach, holding a jar of over 11,000 lady beetles one woman in Hocking County collected over a two-day period. "And once they get into the walls, it's virtually impossible to get rid of them."
The Ohio Lady Beetle Survey focused on data such as age of the house, house and roof colors, where the house was located geographically, and places in the house homeowners experienced lady beetle infestations. Preliminary results unveiled information that the researchers intend to use in future studies.
The survey showed that the age of the house was irrelevant to lady beetle infestations, but 66 percent of respondents who experienced recurring lady beetle problems owned a light-colored house and 40 percent had a dark-colored roof.
"Most of the houses in Ohio are light-colored, so that may not mean much," said Kovach. "But it's possible that the dark-colored roof with a light-colored house may simulate vegetation of a hill or tree line, which is what the insects are truly targeting."
Kovach said the insects use an orienting technique called hypsotactic behavior where they aim for the highest point to over-winter, whether a tree, a hill or a radio tower. The researchers speculate that houses may be targeted as over-wintering sites because they are in the "line of sight" with some distant tall structure.
"The real mystery is why the lady beetles keep coming back year after year," said Kovach. "Do they release pheromones that attract others to the same house or is there something about the smell of dead lady beetles or insect feces that keeps them coming back?"
Eighty-six percent of respondents surveyed stated that lady beetles congregated around house windows, reaffirming the fact that the insects like warm, dry areas. It may also be the reason why the majority of lady beetles are also found in bedrooms and living rooms.
The survey results also showed that over 50 percent of the respondents who experienced high lady beetle infestations lived in houses surrounded by woods, as opposed to farmland, open fields or other homes.
"The fact that there are woods present seems to be an important factor in lady beetle migration. The insect is an arboreal species, which means they prefer to live in trees," said Kovach. "But there's something going on there, whether it's air currents, heat, smells or something else that is pulling them away from the woods and into homes."
The researchers are currently developing a capture and release program to determine how far away the insects fly and temperature-dependent aggregation models to determine when the beetles start and finish massing. "If we can develop some theories now, then we'll have something we can work with for next year," said Kovach.
The researchers are also evaluating pesticides that would have the longest residual effect on the insects. "If we can predict when they will start and finish massing and determine the most effective pesticide, then we can better time pesticide applications to minimize use" said Kovach.
Other OSU IPM program researchers participating in the study include Margaret Huelsman, Bruce Eisley, Curtis Young and Jim Jasinski.
Below is the IPM town meeting schedule:
September 6, 7-9 p.m., Tuscarawas County
Jim's Place (annex of the First United Methodist Church),
228 W. High St., New Philadelphia
September 13, 7-9 p.m., Franklin County
Kottman Hall, Room 103
The Ohio State University, 2021 Coffey Road
(NO PERMITS WILL BE REQUIRED TO PARK ON CAMPUS)
September 24, 7-9 p.m., Athens County
Athens City Recreation Center, 701 E. State St.
September 25, 7-9 p.m., Pike County
Verne Riffe Vocational School, 175 Beaver Creek Road
For more information on the town meetings, contact the Ohio Lady Beetle Hotline at (800) 678-6412. The information can also be accessed on the OSU IPM website at http://www.ag.ohio-state.edu/~ipm/.