Spiders in Denver, Colorado
Colorado is home to many different types of spiders – garden, house and poisonous.
Among the most common indoor spiders are funnel web spiders, cobweb spiders, cellar spiders and sac spiders. Though these spiders do not pose a medical concern, large populations can become a nuisance. Infestations typically occur in dark, moist areas that provide limited human disturbance – garage areas and basements are examples of ideal indoor habitats.
It is important to note that Colorado is home to the poisonous Western Black Widow. Though the spiders are not typically aggressive, they will bite if disturbed. Neurotoxins in the venom can cause muscle or chest pain, abdominal discomfort, swelling of the extremities, anxiety, restlessness, or difficulty breathing and speaking. If you have been bitten and are experiencing any discomfort contact your physician or other health professionals.
Mature females are typically black in color and have a distinct “hourglass” marking on the underside of a bulb shaped abdomen. The males have more variation in color and a longer abdomen. Females typically spin cobwebs in dark corners or holes near the ground. They have also been know to use rodent burrows, wood piles, well houses, electrical boxes or other secluded areas as a place to live.
Brown Recluse spider bites are also poisonous to humans. However, it is important to note that Brown Recluse spiders are rare in Colorado. The spider’s common habitat includes the mid-western and south-central states. Brown Recluse spiders can be brought into Colorado from the common habitat regions, but rarely survive. The Denver Museum of Nature and Science can identify any suspected Brown Recluse specimen.
Wolf spiders may appear menacing, but are generally considered harmless. They can range from 1/2″ to 2″ in length and typically live in garden or field areas. Wolf spiders do not construct webs, but rather hunt their prey. Occasionally they will enter homes if their natural habitat is disturbed.
NOTE: Due to their brown patterning, Wolf spiders are sometimes misidentified as Brown Recluse spiders.
**For more information regarding common spiders in Colorado, visit Colorado State University’s article “Spiders in the Home.
Spider Reproduction and Peak Activity
Reproductive patterns will very between species, but most spiders in Colorado breed and lay their eggs between May-Sept each year. Spider sightings often increase during this season as males and females participate in mating rituals. Once fertilization has occurred, the female spider can lay dozens of eggs in protected egg sacs. The egg sacs may hatch and spiderlings emerge within a few weeks to months of when they are laid.
Life span can also vary by specie, but most spiders in Colorado can live between 1-3 years. This means that while spiders may be less active during the colder winter months they do not die. They will remain indoors or protected cracks/crevices along the exterior of the home and emerge when it is warm. Since the Denver Metro area is fortunate enough to have ample sunshine and warm weather during the winter, spiders don’t have an “off” season.
Tips for Limiting Spider Activity
Spiders are an important part of our ecosystem as they can provide control for other species of insects, but large populations can become a alarming. There are several things you can do to limit spider activity on your property and maintain manageable spider presence.
- Eliminate brush or debris along the exterior structure of your home to limit spider habitat.
- Keep vegetation trimmed away from the exterior wall of your home – especially vines or thick foliage.
- Store firewood away from the structure of your home as spiders love to build webs in the spaces between logs.
- Check door and window seals the ensure they are functioning properly and caulk any visible cracks/openings into the home. Please note that this will not completely eliminate a spiders ability to enter your home, but it can limit their ease of access.
- Keep interior areas clean – vacuum corners regularly, limit clutter, etc.
Who Can Help with Spider Control?
Proactive treatment is key to maintaining control of spider populations on your property, so when spider populations become unmanageable with the tips listed above, it may be time to seek professional spider extermination services. Whitmore Pest and Wildlife Control offers one-time spider extermination treatments as well as ongoing spider control maintenance plans. Our technicians can offer peace of mind by thoroughly treating common spider breeding areas inside and outside of your home. We can also provide cleanup services to remove cobwebs and/or egg sacs on the exterior of your home. Don’t let spiders take over your home… let us eliminate what’s bugging you!
What our customers are saying:
Whitmore Pest Control was very courteous and informative. Marvin took great care of our home and was sure to answer any and all of my questions. We had a small mouse issue and a large spider issue. I’ve only seen 1 spider since Marvin completed the work and it was the day after he sprayed, and the spider was already dead. I’m very pleased, and will be recommending Whitmore’s services to others.”
-Mrs. S. of Denver, CO
“Very knowledgeable, nice and professional service.
Since they have started spraying my yard and house I haven’t had any spiders or bugs in my house, they always go out of the way to do an excellent job and even informed me last time that we might have a bat living in our awning due to the bat droppings near our door. They are always professional and courteous and I would recommend them and do recommend them to everybody I know.”
-Tom D. of Castle Pines, CO