Ever watch a nature documentary with a bunch of exotic and terrifying animals and think to yourself, “thank goodness I live here”? The Colorado Front Range is fortunate to not have too many dangerous bugs or wild animals; outside of rattlesnakes and the occasional mountain lion, there isn’t much northern Coloradans need to fear when they trek through the outdoors.
But while the threats aren’t numerous, there are still a few critters to watch out for, especially if you see them in or near your home. From northern Colorado’s pest control experts, here’s a rundown of the most dangerous pests in our neck of the (thankfully non-tropical) woods.
1. Black Widow Spider
The Western Widow spider (Lactrodectus hesperus), known as the black widow, is the only venomous spider to regularly inhabit Colorado. Despite its fearsome appearance and neurotoxic venom, this spider is not particularly aggressive, and male widows are incapable of biting people. Even female widows rarely bite outside of their webs.
Habitat & Characteristics
Black widow webs are distinguished by their irregular shape, unlike typical house spiders that weave orb- or funnel-shaped webs. Widow bites were historically more of a problem here because they would often build webs in wooden outhouses; now, bites usually only happen when people unknowingly disturb a female in her web. Females build webs in wood piles, sheds, basements, crawl spaces, construction openings, and other kinds of dark, undisturbed areas.
Males do not build webs and spend most of their lives wandering around in search of females. Once a female builds a web and lays an egg sac, she will not leave the nest to hunt or for any other reason.
Although rare, female black widow bites can produce a range of unpleasant symptoms, including muscle pain and chest tightness, stomach cramping and nausea. The pain can be severe. These symptoms usually subside after 48 hours but can last longer depending on the amount of venom injected. While widow bites can be painful and the effects are temporarily debilitating, there is typically no risk of death or more severe symptoms.
Identification
Mature western widow females are among the most distinctive of all spiders, sporting a shiny black body with red hourglass markings on their abdomen. These markings only show up in mature females; immature widow spiders can have multi-colored markings. Mature males look quite different from mature females, with longer front and hind legs, brown-black bodies, and red, white, or orange splotch markings.
Because they have a similar body shape, sometimes feature red markings, and weave a similarly messy web, cobweb spiders (Steatoda ssp.) are often mistaken for widows, even earning the nickname “false widows.” However, their markings will not include the distinct hourglass shape of the western widow, and they typically have a lighter body color.
(Steatoda – nonvenomous)
Exclusion & Control
Since most widows occupy dark, undisturbed places and females rarely venture out of their webs, you probably wouldn’t notice one even if it was sitting a few feet away from you. Widows are generally harmless unless their webs are disturbed, but unlike other spiders, black widows should always be removed from homes to fully prevent accidental disturbances and bites. Males should also be removed, as they could indicate the presence of females.
Discourage widows from nesting in your home by keeping all corners, basements, and crawlspaces clean or sealed. In the fall, widows nesting outdoors may attempt to transition inside, so be extra aware of these places during that time of year. Since they prefer dark places, ensuring all these spaces are well-lit will also deter widows from nesting.
If you discover a widow, they can be killed or captured and removed; removal requires skill and thick gloves, and probably shouldn’t be attempted. A thick boot, a covered glass jar, or your typical insecticides should take care of most widows (be extra cautious when using insecticides so you don’t accidentally spread poison in your home). Large populations of widows require professional spider control services.
2. Kissing Bug (Conenose Bug)
When we think of dangerous bugs in Colorado, the western widow rightly pops into mind. However, disease-carrying bugs often pose a bigger threat than ones that simply bite or sting, as even the black widow’s venom rarely results in severe illness.
One bug that carries a particularly nasty—though extremely rare—disease, is the western conenose (Triatoma protracta).
Habitat and Characteristics
Also known as “kissing bugs,” western conenose bugs are not a common site around the Front Range or other urban areas of Colorado. They are usually only found on the Western Slope, in remote natural areas, and specifically near nests of wood rats, which they feed on nocturnally.
However, conenose bugs make this list because their droppings contain a parasitic disease known as Chagas that can potentially infect humans. Chagas disease is hard to detect because its first phase is largely asymptomatic beyond minor illness, but chronic cases can be debilitating over time.
Again, conenose bugs like to hang around wild rat nests in the woods, so it is rare that any come into contact with a human, much less cause a Chagas infection. The discovery of Chagas disease within these bugs is so recent, in fact, that there have been no reported human cases of Chagas disease in humans in Colorado.
Identification
The trick with kissing bugs isn’t determining whether you have one in your home—you probably don’t, unless you live near a giant nest of wood rats (which would have its own set of pest control considerations). Instead, the trick is identifying the other common, harmless bugs that resemble it so you can rest easy:
Masked hunters are similar in appearance to conenose bugs but are generally darker in color; they can occasionally wander into homes accidentally or to hunt other insects. These and similar insect-eating bugs deliver a painful bite if picked up, but carry no venom or diseases.
Western conifer seed bugs are also similar in appearance to kissing bugs but are harmless shelter-seekers who may come into homes in the fall.
Zelus luridus has no common name and is similar in size and shape to conifer-seed bugs and masked hunters, but it is pale green and brown. You’ll most often find these hanging out on leaves in your garden, although they may wander onto porches or into homes. They are completely harmless.
3. Rattlesnakes
While not considered common home “pests” (thankfully), rattlesnakes can be more common than one might think in Colorado, and they earn a mention on this list because of their association with rodent prey that we are often called to control.
Habitat & Characteristics
Like all predators, rattlesnakes will be drawn to areas with large rodent populations, so if you have a major rodent problem in Weld County—especially on the exterior of your property—you should expect the presence of all kinds of snakes, including rattlesnakes.
Rattlesnakes prefer to nest in damp, cool spaces, which can include rodent tunnels or underneath homes or buildings. In the wild, they often make dens under piles of rocks or rocky outcroppings.
Unlike most other kinds of snakes, female rattlesnakes give birth to live young each fall. Fall is typically their most active season, as they will be giving birth and searching for suitable hibernating places.
Identification
(Prairie rattlesnake)
All rattlesnakes are pit vipers, a class of snakes that share special sensory pit organs atop their heads and deliver venom through hollow-pointed fangs. The venom is stored in large glands near their mouths, resulting in a distinctive, triangular head shape compared to the narrow heads of nonvenomous snakes. The most common type of rattler found in Weld County is the prairie rattlesnake (Crotulus viridis).
The bull snake (Pituophis catenifer sayi) is a nonvenomous snake that shares a habitat with rattlesnakes; it is also of similar size and has similar markings and coloration. However, in addition to lacking a rattle (which may or may not be visible), bull snakes lack venom glands and so will have a much narrower head.
(Bull Snake – nonvenomous)
Rattlesnakes are among the least aggressive types of venomous snakes, and of course will always warn you by rattling their tails if they are threatened. This sound is extremely distinctive and is one reason why rattlesnake bites are uncommon in Colorado.
People most often come across prairie rattlesnakes in the late afternoon hours, as the snakes may be laid across trails or starting to make their way back to their burrows after basking in the sun. Even so, they generally avoid popular hiking trails and other spots that draw large amounts of people.
Exclusion & Control
The best way to keep snakes away from your property is to control mice and rat populations, and seal off any openings so they stay out from under decks, buildings, and sheds. They may also hide beneath logs or small brush piles, so keeping a clean yard will help, too. Beyond that, there are a number of snake-specific products you can find to humanely deter snakes from coming near your property.
If you spot a rattlesnake on your property or suspect you may have some other snake problem, contact Colorado Parks & Wildlife right away. Bug Control Specialist can help with rodents and bugs, but wayward reptiles are the state’s jurisdiction!
4. Wasps
Wasps are probably not a creature you’d expect to see in a “most dangerous” post, but their numbers, proximity to humans, aggression, and potential to trigger anaphylaxis in some people are more than enough to justify being listed here.
Habitat & Characteristics
The most common types of wasps found along the Front Range are yellow jackets and paper wasps.
Yellow jackets build nests both in the ground and in wall voids, attics, or high corners. They are extremely aggressive stingers who will attack in swarms if their nest is disturbed.
Paper wasps are similar in appearance and size to yellow jackets, but they have longer legs that dangle during flight, and their nests have a distinctive umbrella shape. While not as aggressive as yellow jackets, they will also attack and sting in defense of their nests.
Beyond these two most common species, in Weld County you may also encounter bald-faced hornets (actually a type of wasp). Unlike the more common yellowjackets or paper wasps, bald-faced hornets build large, cylindrical nests. There’s also the solitary mud daubers, who live in underground burrows. These species are less common, but are still dangerous to anyone with an allergic reaction to bee or wasp venom.
And, although they aren’t found in Weld County, if you want a good reason to avoid the southern part of the state, tarantula hawks are a wasp species that carries one of the most painful stings in the animal kingdom.
Exclusion and Control
Yellow jackets and paper wasps love to build nests in anything that resembles a roof overhang. To keep them out, regularly inspect and sweep high corners of porches, balconies, and eaves. If you have persistent nests appearing, you can treat these areas with natural repellents, including oils of peppermint, clove, and lemongrass.
We cannot stress this enough: if you are allergic to wasp stings, DO NOT under any circumstance attempt removal yourself. Call Bug Control Specialist, and live to fight another day!
Even if you’re not allergic to wasps, battling a live nest full of them can be painful, and you might not even solve the whole problem. If you’re using chemical pesticides, be sure to read the labels, always use as directed, and use proper protective gear; shooting streams of aerosol poisons all over the place isn’t a recommended professional eradication strategy.
Get Rid of Dangerous Pests with Bug Control Specialist
For more questions on Colorado’s dangerous critters, product recommendations and exclusion tips, or to schedule reliable exterminator services in Weld County, contact Bug Control Specialist today!