There's a new type of home invader in South Texas, according to Dr. Raul Villanueva, an entomologist at the Texas AgriLife Research and Extension Center at Weslaco.
They don't carry guns or break down doors, but they can cause allergies if they are present in great numbers, he said.
"We're getting lots of calls about these tiny insects that suddenly show up in homes," Villanueva said. "But they cause little harm, and the best way to deal with them is to just vacuum them up."
They are called springtails, or Collembola; tiny organisms that are attracted to anything white.
"They are about 2 mm long, a little bigger than a pinhead, about a 16th of an inch," he said. "They are very common and have always been here, but with rains their numbers tend to build and they like to invade homes to get out of the humidity.
Villanueva said once they are in your home, they are hard to miss.
"They cluster on windows or they might get attracted to the white sheets on beds," he said. "One caller told me her husband developed an allergy after they invaded her house, and that could be caused by either their excrement or the skin they shed."
Other than the chance of causing an allergic reaction, Villanueva said they are harmless and actually play a positive role in nature.
"If you put a white sheet of paper on your lawn, you can see them jumping around on it. Their mouth parts are not suited for biting or sucking blood, so they are not harmful. In fact, they feed on decaying matter like leaves, so they are actually beneficial," he said.
But not in the home.
"Don't bother using insecticides," Villanueva said. "Instead just vacuum them up, caulk your windows and seal your doors so they can't come in. And don't overwater the lawn. Irrigating just once a week will help keep their numbers down."
Most of the calls Villanueva has gotten about the insects have come from an area roughly between McAllen and Weslaco in the Lower Rio Grande Valley, though they could show up anywhere.
"When they congregate by the thousands in your home, they can look alarming, but they're not," he said.
AgriLife Extension entomologists and integrated pest management specialists in Central Texas have also received reports of insects popping up in surprising numbers this summer. These include red katydids, false chinch bugs and cicada killers, according to Noel Troxclair, an entomologist at the AgriLife Research and Extension Center at Uvalde.
While masses of red katydids can damage trees, especially the canopies of oaks, they do not tend to inflict much long-term damage on the areas they choose for their summer home, he said.
For more information on springtails, call Villanueva at 956-968-5581