There is something magical about spiderwebs with dewdrops in the morning sun.
While you may not like spiders in your house, there is only one medically significant spider documented in Idaho, the western black widow. All others should be considered beneficial. Even the black widow is beneficial. It’s only a problem when it bites a human, and they don’t go looking for people.
Spiders are generalist predators and will eat anything they can catch.
There are over 40,000 species of spiders and while it takes an arachnologist to be able to identify most species, spiders can usually be placed in a grouping based on their hunting habits (web-building, passive hunting, and active hunting), then there are some subgroupings of those major groups. The subgroupings are usually determined by the type of web they spin, body shape, eye number (6 or 8) and eye pattern. Here are some of the web-building spider subgroups you will find in eastern Idaho.
Cellar spiders inhabit crawl spaces, cellars, caves, and leaf litter. Their webs are irregular, unkempt looking strands. They have eight eyes—two groupings of three on each side and a smaller pair, front and center. The legs are long and slender.
Cobweb weaver spiders
The most notorious cobweb weavers are the black widow and common house spiders. Their webs are an irregular maze with sticky strands. The abdomen is very bulbous. Their eight eyes, when viewed as two lines across the face, form an elliptical shape.
Sheetweb spiders are tiny. The webs are sheet-shaped, bowl-shaped, dome-shaped or irregular, and small (under 8-inch diameter). Most of them are oriented horizontally. They are most often found in dense shrubbery, among ground litter, or in low-growing plants. The eyes are much like the cobweb weaver spider eyes.
Orbweavers are a large group of spiders, small to large in size. They build two-dimensional webs that are vertically arranged in areas of insect flight zones. The webs are mostly symmetrical. The eyes are equal-sized in two closely-spaced rows, with a pair on each side of the head and two pair in the center of the face in a nearly square formation. They are found in forests, tall grasses, bushes, and on structures. Cat face spiders and yellow garden spiders are in this group.
Longjawed orbweaver spiders
Longjawed orbweaver spiders build a web similar to the orbweavers, but their abdomen is narrower and their fangs are much larger. They are found in meadows, shrubs and tall grass, often near water.
Funnel weaver spiders
Funnel weavers produce a web that is cone-shaped. The webs are produced in dense shrubs, tall grass, fallen trees and branches. The eight eyes are similar in size and form two closely-spaced arches over the face. The grass spider, domestic house spider and hobo spider are in this subgroup.
Conserve and encourage spiders
- Maintain a diverse, no-till planting area.
- Plan for summer-long blooms to provide hunting areas.
- Allow for some pests to attract spiders.
- Plant cover crops.
- Be cautious with pesticides that are specific to arachnids.
Spiders are fascinating creatures. Unlike some insect species, spiders cannot transmit any communicable diseases to humans. Be careful around wood piles and pumphouses where black widows like to set up residence. Otherwise, let them do their job and they will help you with your pest control efforts.
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