No cause for worry regarding ladybug infestations on campus

Ladybugs have been appearing in dorms and academic buildings across campus. University officials say that they pose no threat to students. (Junbo Huang/The Daily Campus)

Recent accumulations of ladybugs in dorms and academic buildings are no cause for concern, University of Connecticut officials say, as the beetles are not inherently dangerous to students.

Students and staff have reported ladybugs entering and conglomerating in several buildings, especially near windows in the corners of rooms. Assistant Director of Building Services Aris Ristau said the bugs are no cause for concern, as they generally enter buildings seeking warmth as the weather cools each year.

“We typically see higher numbers of ladybugs during the fall months as they are drawn to the warmer temperature of buildings,” Ristau said. “Ladybugs are not known to carry disease, are harmless and do not damage structures.”

Students can place a work order if they need assistance with clearing the bugs out of their dorms, Ristau said. However, since the bugs are harmless, it is considered a lower priority than other building safety needs.

“It’s not unusual to see more ladybugs than usual at this time of year, given the temperature variations,” UConn spokesperson Stephanie Reitz said. “UConn sends our housekeeping crews to clean them up at locations when we learn of large numbers of the bugs at a certain spot.”

The particular type of ladybug seen within buildings is actually not native to Connecticut, UConn assistant extension professor and entomologist Ana Legrand said. This particular species is known as the multicolored Asian ladybeetle Harmonia axyridis, which was initially brought to the United States for the purpose of pest control, Legrand said.

“It was originally introduced in the 70’s,” Legrand said. “The (exact) origin isn’t certain. They help with a lot with the number of insect pests… They’re a very good predator in orchards.”

The Asian ladybeetles tend to be orange to red-orange, and eat soft-bodied insects such as aphids and small caterpillars, Legrand said.

During the winter, the Asian ladybeetle seeks out shelter in the form of heated buildings. Native Connecticut ladybugs will instead winter in rocky crevasses, under mulch and buried in leaf mold, which is why Asian ladybeetles are the primary species found in buildings, Legrand said.

“(The Asian ladybeetles) do that to look for refuge to pass the winter time,” Legrand said. “Anywhere where’s there’s a gap (in the building), they get in there. It’s an issue we contend with every year.”

It only takes an opening one-eighth of an inch in size for a ladybug to gain entry. The insects will usually enter through opened windows, gaps in caulking and insulation, under doorways and even in entryways for wires and pipes, Legrand said

The ladybeetles do not harm buildings or people, though if disturbed, the bugs may spray a defensive chemical from their joints. The chemical, while harmless, has a strong bitter odor and may stain the walls a yellow color, Legrand said.

“In high infestations in close quarters, it has been reported that people have allergic reactions,” Legrand said. “(However), it’s not common. You’d need a very enclosed area where ventilation is an issue.”   

The color and location of the building can be a factors in attracting the ladybugs, as structures with lighter colors and that are located near woods or large amounts of trees tend to see higher aggregations of the insects.

Once inside, the insects gather in corners in higher areas in order to conserve warmth, and are attracted to one another. Severe infestations, though rare, can see hundreds of bugs in one mass, Legrand said.

The main way to keep the insects out is to seal points of entry by caulking up windows, sealing cracks in the foundations and repairing damaged windows, Legrand said.

“The main thing is to find a way to prevent entry,” Legrand said. “It’s a lot of structural fixing that will have to be taking place, especially if it’s a recurring problem.”

Students can remove the ladybugs by vacuuming them up and then either emptying the bag outside or double sealing the bag before placing it in the trash. Some people may opt to keep the ladybugs they gather in a moist, dark place so they can release the insects in their garden during the spring, Legrand said.

Students should not use insecticide, as bodies of the dead ladybeetles can attract worse pests such as carpet beetles that can do damage to clothing and furniture, Legrand said.

Though the ladybugs can be a nuisance, they do more good in helping agriculture than harm, Legrand said.

“They’re a good natural control to many pests,” Legrand said. “Some people think that they’re good luck.”    


Marlese Lessing is a staff writer for The Daily Campus. She can be reached via email at marlese.lessing@uconn.edu. She tweets @marlese_lessing.