Carabid beetles spotted en masse in South Central Texas

SAN ANTONIO — The past few weeks have generated several calls to the Texas A&M AgriLife Extension Service about an explosion in the beetle population in South Central Texas, said the agency’s entomologist for Bexar County.

Many residents have been surprised and concerned about the sight of large clusters of small black beetles teeming outside their homes, said Molly Keck, AgriLife Extension integrated pest management specialist.

A proliferation of Carabid beetles, a fast-moving predatory insect, has been reported in the South Central Texas area. (Texas A&M AgriLife Extension Service photo courtesy of Mike Merchant)

A proliferation of Carabid beetles — fast-moving predatory insects — has been reported in South Central Texas. (Texas A&M AgriLife Extension Service photo courtesy of Mike Merchant)

“It’s difficult to say just what has led to this increase,” Keck said. “But there are certain conditions under which insect populations proliferate, and I’m sure the recent rains have been a factor.”

Keck said the beetles she has received reports about and personally identified are Carabid beetles.

“These are predatory, opportunistic beetles that feed on other insects,” Keck said. “They are ground foragers and are commonly found in a variety of habitats.”

She said in urban areas the beetles seem to be attracted to light-colored buildings, but tend to remain outdoors where there is better opportunity for survival.

“We’ve had reports of these elevated beetle populations throughout San Antonio and Bexar County, and as far north as San Marcos,” she said.

South Central Texas is no stranger to upticks in the Carabid beetle population, Keck noted, adding that similar beetle proliferation, as well as explosions in other insect populations, have occurred in the region.

“Sometimes it’s beetles; sometimes it’s crickets,” she said. “Insects tend to have population ups and downs.”

She said entomologists tend to group insects into three general classes – beneficial, non-beneficial and neutral.

“I’d say these beetles are in the ‘beneficial’ category as they pose no medical, health or sanitation-related threat to humans and because they serve as food for other animals in the ecosystem, such as birds.”

However, she added, in such large quantities the beetle can be annoying and even “pesky.”

“Since they don’t pose any real threat, you don’t really need to worry too much about controlling these insects,” Keck said. “Besides that, these insect swarms tend to come and go and we’re already seeing a drop-off in their numbers. The beetle numbers probably will return to normal in just a few more weeks.”

Keck said South Central Texas residents can expect additional increases in insect activity in weeks to come.

“Many people have already noted a significant increase in area mosquito populations due to the rains. And other insects, such as fire ants, are becoming more prevalent again.  As far as beneficial insects are concerned, I’m hoping the rains will also stimulate the feral honeybee population, as these pollinators are very important to the production of numerous plants and crops.”




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