Kansas insect expert warns people to watch out for black widow, brown recluse infestations


A Kansas entomologist says summer heat is bringing two notorious spider species into greater contact with people.

Kansas State University’s Jeff Whitworth commented on brown recluses and black widows in a recent publication from the college on June 20. He said the spiders are laying eggs this month, leading to potential problems for homeowners who may not be experienced with the arachnids which can deliver painful bites, according to the CDC.

Black Widows

Black widows are recognizable for their black coloration and red markings which sometimes appear as an hourglass shape. The spiders are have a reputation for being dangerous due to their ability to deliver painful and sometimes even fatal bites.

“Right now, the black widow can be found around out-buildings, garages, old sheds and those areas,” Whitworth said. “And right now, of the one’s I’ve seen, they are producing egg cases.”

Whitworth said the spiders are actually quite timid and more likely to run away than try to fight back if disturbed, according to K-State. However, the spiders will stick around if their egg cases are nearby.

“If you hang around…they’ll act a little more aggressive,” Whitworth said. “They’ll rear up on their back legs. If you brush up against them or stand there for a minute, they may come out and actually bite you.”

Black widow spider bites can leave you with pain which lasts several hours and lead to symptoms such as fever, increased blood pressure, sweating and nausea. People bitten by these spiders should seek medical attention.

Whitworth highlights the main concern people should consider which is the black widow’s ability to reproduce quickly. A lone black widow female may create up to four egg cases in a given year.

“And inside of each case may be 100 to 200 eggs, and when those hatch, you’ll have a whole bunch of little black widow spiders,” Whitworth said. “So, if you’re wanting to eradicate the black widow spider around your house or yard, now’s the time to go around and find them.”

Spiders hatching from these egg sacs typically appear within 20 or days after the eggs were laid. These young spiders are also dangerous as they contain a toxic substance which can harm pets or children if swallowed.

Strategies you can use to avoid encountering these spiders is to make sure to reduce clutter in and around your properties to reduce hiding places for them. You can get rid of egg cases using alcohol or fire. If a black widow lands on you, try to flick it away as crushing it may push its fangs into your skin.

“If you suspect you have been bitten by a black widow, contact your healthcare provider and show them the suspect if you can capture it safely,” Whitworth said.

Brown Recluses

Similar to black widow spiders, brown recluses are also becoming more active and laying eggs. They can also deliver a painful, though often not fatal, bite.

“They’re laying eggs right now,” Whitworth said. “They might make a little bit of a webbing, but for the most part, the brown recluse goes out searching for food from under or behind other objects, and from which there is often a small, loosely constructed web.”

These spiders can often be found hiding in cardboard boxes and insulation inside structures. They tend to become more active as the weather becomes warmer.

“We’ve actually sampled and trapped hundreds of brown recluses in a building where we were doing research,” Whitworth said.

Brown recluse bites can lead to pain, bleeding and an ulcerous wound, according to K-State. Often, the bite area will lead to a slow-to-heal wound with significant scarring. In rare cases, a bite can lead to a potentially life-threatening systemic illness.



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