With a Bright Face
Marla Mertz, Naturalist, Marion County Conservation

Just as spring abounds with new life, fall seems to be neck-and-neck in the rush of creature retirement. Like it or not, insects and spiders are the most abundant creatures on earth. In Iowa, hundreds of different species of insects, including important pollinators, have ventured from egg to adult, worked all summer to help us prepare food resources and are now preparing for spring regrowth (laying eggs), retirement, and death. 

One of the most commonly found orb weaver is the yellow garden spider. Other names are writing spiders, black and yellow garden spiders, and corn spider.
The sun is warming to the darker underside. Heat is necessary for their activity.

As the north winds bring cool air, migration and dewy mornings, the glistening of spider webs seem to appear from out of nowhere. Those large, spiraled webs are dotted throughout the landscape like works of art. The most abundant of Iowa spiders are called Garden Spiders or Orb Weavers and are probably one of the most fascinating. They offer great benefits to our ecosystem by controlling numerous insect pests, are not aggressive and seem to flee immediately upon feeling threatened.

With open mind, let’s take a short venture to your nearest garden or wildlife area, camera or not, and take a peek at a few of Iowa’s Orb Weavers. Known for their colorful, intricately patterned abdomens, garden spiders are the common name for the genus Argiope, which means “with a bright face” in Latin. As a relative to an insect, there are some noticeable differences. At one time or another, we have probably learned that insects usually have six (6) legs and spiders have eight (8). Insects have three (3) main body parts (head, thorax and abdomen) and spiders have two (2) body parts (the head and thorax fused together, called cephalothorax, and abdomen). Insects have antennae, normally two (2) pairs of wings and two (2) compound eyes with several simple eyes. Spiders have no antennae, no wings, and have 8 simple eyes, but no compound eyes.

Most eight-leggeds are not long-lived creatures. Depending on where you live, most orb weavers don’t live a full year. For the female, she may die at the first hard frost. She has probably mated and her young may remain in the egg sac in a dormant state until the following spring. There is a high mortality rate to the egg sacs and are quite vulnerable to wasps, flies, and other insects. The male is also more of a traveler. During his travels, he may choose to court a female by ‘plucking’ at her web. Male weavers usually die after mating.

A liquid silk emerges from the spider's spinnerets and hardens when it is exposed to air. There are different kinds of silk for different uses.
With patience you can see the silk emerge from the spinnerets as the sun hits the liquid. It can even have the appearance of smoke.

Spiders are unique as they spin silk from spinnerets on their abdomens. The orb weavers get their names by the shapes of their webs and are the infamous design for Halloween decor. They spin webs of smaller circles within larger circles, similar to spokes on a wheel. The spokes of the wheel usually go from the center outwards to their anchoring points, like a flower, stem, or leaf. Once the main structure of the web is complete, a sticky layer of silk is laid down in circles between the structured points. The spider uses one set of legs on the interior circle and one set on the next structural layer where the “sticky line” is created in the middle. 

Some spin a thick zigzag pattern through the center of their webs. The scientific term for the zigzag pattern is called the stabilimentum.

There are a few theories as to the purpose of the patterning, one being that it alerts birds to their elaborate webs; it may deter predators by exaggerating their size; it may assist in the capture rate by adding sticky surfaces, but there are no proven theories about the zigzags. Whatever the reason, the intentional artwork has given the weavers another name, “the writing spider.” 

The orb weaver is sometimes referred to as "the writing spider" due to the zigzag patterning within the web.
These beautiful spiders give such great inspiration to keep revisiting their home, as their web may change daily. It can be a head-scratcher to unfold their little secrets. Windblown seeds and small insects in the web may appear to be untidy one day and be totally cleaned and repaired from wind damage the next. It makes you wonder if they stayed up all night to clean their house or did something happen to them through the night? Surprise! Cool fact: They probably just ate their web from yesterday and created a new one today.

Whether it is in your backyard, a prairie, woodland, or roadside ditch, insects and spiders are more abundant than any other group of animals. They have a very important role to play in our environment and, undoubtedly, you will encounter a few along the way. With a curious mind some will find it absolutely fascinating to peek into their world. We don’t want to solve all mysteries and wonders, but enjoy a little bit of their magic.

Attention Educators and Kids! Do you like geometry? That might be a scary question for some of us, but there are some really fun activities that can apply principles of geometry, architectural design, and engineering all by learning and observing our backyard wildlife. Check out these links and learn from the Orb Weavers! Make your own observations and activities involving wind direction, temperature, angles, heights, direction of a spider’s abdomen and surface area covered. Please note that spiders and their webs should only be observed, not damaged and or harmed.

Learn more about spiders here:

  • Project WILD Activity Guide - Project WILD is an interdisciplinary, supplementary environment and conservation education program for educators of kindergarten through high school young people.
    • Spider Web Geometry: Math, Science, Language Arts, Art
    • Interview A Spider: Discussion, reading, research, creative writing, interview
  • Spider Webs: Creepy or Cool? - MathematicalIngenuity
  • Garden Spiders: Weavers ofDelicate Webs
  • Wild Kratts - Secrets of theSpider’s Web (SO2E08) - Storyline: Two miniaturized Kratts explore the world of the spider and how it creates its web, finding clues along the way that indicate what spider silk is made of that will help Aviva to replicate it.
  • Keepers of the Animals, Native American Stories and Wildlife Activities for Children by Michael J. Caduto and Joseph Bruchac, Sticky Web activity, page 37 and other fun activities about webs and spiders
  • Iowa Public Radio Talk of Iowa with Charity Nebbe and Iowa State University Extension Entomologist Donald Lewis.
Orb Weaver photo album in Google Photos.

 This web appears to have circles within circles.

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Raptor Viewing Etiquette

We should all observe good raptor viewing etiquette, not only during the nesting season, but also during this time of migration. 

Remember that raptors are protected under the Migratory Bird Treaty Act and bald and golden eagles have additional protections under the Bald and Golden Eagle Protection Act.

Upcoming Programs and Opportunities


Check back for program details.

Who am I? for the week of 24 October

So, let’s get down to it. Put on those thinking caps, grab your friends and family, and let’s play! Remember — no cheating!

  • I live around wet, grassy spots,
  • I probe in the mud for small bugs,
  • I am heavily camouflaged,
  • I have really short legs, and
  • Some think I am a joke.
What am I? Make your guess, and then go here for the answer and more interesting facts. Did you get it right?! If not, no worries — you’ll have another chance next week!

In the news...

Check these out!

Iowa Young Birders - Check out this group formed in 2011 to help young people experience the joy and wonder of finding, seeing, and identifying birds! Check out the Iowa Young Birders website for info and field trip opportunities! <jealous!>

Developmentally-appropriate activities for early childhood learners to explore the natural world can be found at KinderNature!

Healthy and Happy Outdoors - Learn more about this Iowa Department of Natural Resources initiative here. Register with the program and record your outdoor activities in Iowa parks and recreation areas with each recorded activity a chance to win outdoor gear in a drawing.  The site also has a search feature for finding outdoor activities in Iowa.

Visit MyCountyParks.com to check out a park or wildlife area you might want to explore managed by one of Iowa's 99 county conservation boards! Look here for events and activities, too!