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By Bruce Rottink, Volunteer Nature Guide and Retired Research Forester
Some of the smallest, but most important predators at Tryon Creek State Natural Area (TCSNA) are our spiders. Spiders are the most voracious predators in the world, consuming far more prey than larger, more dramatic predators like owls and coyotes. It was estimated by an eminent spider scientist that the all world’s spiders together each year consume a weight of insects greater than the weight of the human population of England.1
Spiders: Voracious Predators
Spiders catch their prey in variety of ways, the most obvious being those that weave webs. Just a brief look around TCSNA reveals that we are home to many different kinds of spiders and their webs.
The Orb Weavers
The most common and recognizable group of spiders are the orb-weaving spiders, named for the shape of their webs as seen below. These webs are designed to help the spider catch flying insects for food.
After weaving the orb web, the spider will most often wait upside down in the center of the web for some hapless insect to become stuck to, and entangled in, the web. The thrashing motion of the insect trying to escape attracts the spider’s attention. I have also observed a situation where a Douglas-fir needle fell into a web and got stuck. The spider ran down and disentangled the needle and threw it down. Unfortunately it got tangled again lower in the web. The spider went down further, and repeated the process, this time the needle fell free of the web. The spider then returned to the center of the cleaned up web to continue monitoring the action.
Once the victim is in the web, the spider will rush to the insect and inject it with poison to kill it. Sometimes, as seen below, the spider will wrap up the insect for future use.
The Mat Weavers
A slightly less common type of spider is the “mat weaving” spider. I was lucky enough to be in the park on a dewy February morning which highlighted one of the better examples of a “mat” web that I have ever seen. It is a flat web suspended by strands from the overhanging branches. This particular web measured about 3 inches across. Typically, these mat webs are not sticky, and the spider is lurking very near and when an insect gets into the web, the spider rushes over and poisons it before it can escape. These kinds of webs can also be found in the crevices of large tree trunks.
The Funnel Weavers
An even less common type of web is made by “funnel weaving” spiders. The example below was found along the Middle Creek Trail. While it may not be obvious in the photo, this really is a three dimensional funnel. The spider typically waits near the bottom of the funnel.
The Dome Weavers
A fourth kind of web which you may occasionally encounter at TCSNA is the product of a dome-weaving spider. Again, these webs are not inherently “sticky” and the spider will rush towards the insect which is trying to escape the web and inject poison into it. The example shown below was near the Iron Mountain Trail, and was approximately 1 foot wide.
While it is the large spiders and their webs that attract our attention, the population of “tiny” spiders is considerable. Worldwide, more than half of all spider species are less than 2/10 of an inch long1. The spider below was living in a shrub with no obvious spider web. It is important to know that a significant number of spider species do not use webs to catch their prey. This spider MAY be among them.
Shy and Sexy Spiders
Spiders reproduce from eggs. Spiders’ sexual encounters are frequently a one-time event for the males, not because of any spider-y sense of monogamy, but because the female will oftentimes eat the male immediately after mating.
In some species the female will create a protected place to lay her eggs. Examples of this behavior can be seen by looking for folded leaves. When you consider that one small spider was able to fold over this leaf and fasten it together, it is nothing short of amazing. An example found along the Old Main Trail at TCSNA is shown below.
The underside of this folded leaf is shown below. The white areas between the leaf edges are web strands which hold the structure in place. I was able to see an adult spider inside of this “nest” but my attempts to get a good photo of her were not successful.
A less dramatic, but still interesting example is shown below in which the mom spider just rolled up part of the leaf to create her nest. She is still on guard. The empty “skin” just to her left might either be the remnants of her nutritious sex partner, a recent meal or her own recently shed exoskeleton. Just for scale, the brown thing she is standing on is a Douglas-fir needle.
Gently unfolding this leaf just a bit revealed part of her nest, and also excited a few of the newly hatched young spiders into action. The young spiders, one of which is highlighted with the red arrow in the photo below, started scurrying around as I unfolded the leaf, but none of them went very far. After I looked, the leaf rolled up again quite nicely.
The young spiders were almost unimaginably tiny. They were way outside the range of what my camera was designed to photograph. Some species of spiders are reported to eat plant material when they are young, and graduate to insect food as they mature.
Yeah for Spiders!
The spiders of TCSNA are a tremendous aid in controlling insect populations that could devour tons of plants and be much more annoying to our human visitors. While they are a lot less visible and dramatic than other predators at the park, they are likely much more important, at least in the amount of insects they consume. Next time you’re at the Park, pause for just a moment at a spider web, and thank the spider for all it does.
1Dalton, Stephen. Spiders: The Ultimate Predators. Firefly Books Ltd. 2008
By Bruce Rottink, Volunteer Nature Guide and Retired Research Forester
Tryon Creek State Natural Area (TCSNA) is a place which many critters love. Some critters both love the park, and live in it. These range from pileated woodpeckers (Dryocopus pileatus) to raccoons (Procyon lotor) and more. Other creatures don’t live at the park, but they love to visit. These other creatures include humans (Homo sapiens) and their pet dogs (Canis lupus familiaris).
As human beings, we’ve learned that we need to respect and take care of the park if we expect it to be here for future generations. We’ve even figured out that to preserve the park as a place we actually want to come and visit, we need lavatories where we can deposit our feces and urine in the least environmentally disruptive manner.
For our other major non-resident animal, dogs, we’ve got all the feces-related supplies visitors need, and a helpful reminder, at the entrances to the major trials, like you see here:
Based on several years of personal observation, the vast majority of humans who bring their dogs to the park are 101% responsible human beings, who clean up after their dogs. I am happy to share the park with people and dogs like this. One such person, whom I’ve chatted with many times, is pictured below!
And the good news is you don’t have to take it home with you because there are garbage cans on several of the trails near the Nature Center, like the one pictured below at the junction of Old Main Trail and Big Fir Trail:
Sadly, there are what I believe to be a fairly small number of dog walkers who just don’t take the effort to clean up after their dog has a bowel movement. If you need evidence, take a peek below (and this is just a small part of my collection of “dog poop” pictures.)
The Downside of Dog Poop!
I sometimes come to the park primarily for a quiet walk where I can take in views of the beautiful woods. When I see fresh, rotting or bagged dog poop all along, and sometimes on the trail, it really breaks the mood.
Aesthetics aside, dog poop in the park raises other issues. Dog poop can be contaminated with eggs of parasitic roundworms (Toxocara spp.) or hookworms (Ancylostoma spp). People can get these parasites by coming into contact with soil which has been contaminated by dog poop (reference: Centers for Disease Control, Atlanta).
Several dog diseases are spread by dog poop as well. These include Parvo virus, Giardia and Coccidia. These diseases are commonly spread by dog poop. If you walk your dog at TCSNA, don’t you want it to be safe from these feces-spread hazards? Beyond that, TCSNA’s coyotes are also susceptible to the Parvo virus.
What are the alternatives?
Seriously folks, is leaving dog poop sitting around, bagged or unbagged, something you would do at your own home? Tryon Creek is a State Natural Area. You own this place. But it is not just YOUR park, it is OUR park. I, along with more than 4 million other Oregonians, also own a piece of this natural treasure! Let’s work to keep our park clean.
As indicated above, dog poop bags are available at trailheads. These are provide by Oregon State Parks for your use. There are garbage cans at most trailheads and a few major intersections for depositing your full dog poop bag.
To the vast majority of dog walkers who clean up after their animals: Thank you for helping to keep TCSNA clean and safe. I’m glad you and your dog have found your forest home here.
By Deborah Hill, Park Ranger
What have you eaten today that comes from a plant’s fruit? Perhaps you’ve eaten a blueberry, orange, almond, or bell pepper? Are you enjoying the feel of wearing a cotton t-shirt, jeans or sweatshirt? None of these foods or items would be possible without pollinators, (yes, cotton can self-pollinate, but produces more cotton when pollinated by bees).
When we think of pollinators, we usually think of the honey bee. The honey bee (genus Apis) is a social bee that was brought to the Americas by European colonists in the 1600s. Although scientists found a fossilized honey bee in Nevada, it is thought to belong to an extinct species of honey bee. What was pollinating all the plants in North America before the arrival of the honey bee? All the native pollinators of course! Native pollinators are essential to the success of native plants and wildlife, and we can help them survive and thrive.
What is a pollinator?
A pollinator is an animal that moves pollen from the anther (male part) of one flower to the style (female part) of another flower. This cross-pollination fertilizes plants so it can reproduce through seeds. In addition to seed production being important to the plant, many species of wildlife are dependent on those seeds and fruits, and so are humans.
Who are pollinators?
There is a wide variety of animal pollinators including insects (bees, wasps, flies, beetles, butterflies, and moths), birds and bats, among others. Oregon bats are insectivorous (feed on insects) and aren’t pollinators. However, in other parts of the world they are essential pollinators.
Below are a few of our local native pollinators.
What do pollinators do for us?
According to the Xerces Society, a nonprofit organization focused on invertebrate conservation, pollinators are responsible for the reproduction of over 66% of our food crops, and for 85% of flowering plants worldwide. Without pollinators, our food source would be down to wind pollinated grains and meat from animals that feed on wind pollinated plants such as grass. Not only would animals that depend on animal pollinated plants through seeds and fruit suffer, the plant themselves would no longer reproduce. This is of course, a doomsday-type scenario, but it is helpful to entertain this idea to understand just how important pollinators are.
History was made March 2017 when the rusty patched bumblebee was given protection under the Endangered Species Act. It is the first bee to make the list. The US Fish and Wildlife Service can now develop and implement a plan to support this species in making a recovery.
How Can we Help Native Pollinators?
There are simple things we can do with our yards to support native pollinators.
- Plant a variety of native flowering plants: native pollinators prefer native plants.
- Have a variety flower colors: different pollinators are attracted to different colors.
- Have a variety of flower shapes: Pollinators have different shaped mouthparts: hummingbird vs. hoverfly.
- Clump flowers together: clumps of one species are more desirable than scattered plants.
- Have a diversity of plants to flower all season: pollinators are active at different points in the season.
- Create nest sites for pollinators: native bees need a safe place to nest.
- Avoid pesticides.
The next time you are enjoying the results of our hard working pollinators, whether it is a strawberry from a honeybee pollinated plant, or a huckleberry from a native pollinator, take some time to recognize the pollinators that made it happen. Look at the flowers around you and notice who is visiting them and making pollination happen.
Attracting Native Pollinators: Protecting North America’s Bees and Butterflies by the Xerces Society. 2011
Selecting Plants for Pollinators: Pacific Lowland Mixed Forest Province http://www.pollinator.org/PDFs/PacificLowlandrx8.pdf
The Xerces Society. http://xerces.org