The webs of late summer

The continually hot days of July have passed. Recently, they have been more of the seasonal normal (something that we have seen little of in the last several weeks). In addition to the warm and clear afternoons, we also have been experiencing cool and calm mornings. Temperatures that dip into the 50s will often cause the formation of fog, frequently seen as ground or patchy fog, and heavy dew. It is on these mornings that we can see a product of the earlier hot summer days, spider webs.

A hot summer with ample rain, as we had in previous weeks, combined with last year’s mild winter provides great conditions for insects to grow. We’ve seen this in several ways. Mosquitoes and deer flies have kept us alert and the variety of butterflies has been great this year. Dragonflies, damselflies and moths have also been common. And now we see and hear of the abundance of grasshoppers, crickets, katydids and cicadas on these August days. Any time there are good numbers of insects, there is also a large population of their predators. Insects seem to take over the scene on some days, but birds, bats, other insects and spiders are here, too, to feed on them.

Since most spiders stay in the shelter of grasses, leaves and woods, we don’t see them much. But they are present. With lots of insect meals, they have been growing all summer, and now most have reached maturity. Among the diversity of these eight-legged critters, some do not make webs. They use other means to actively hunt food. Many, however, resort to making snares to catch traveling insects. In a method known as sedentary hunting, they make traps that we call webs, and sit back either in the web or nearby to wait as their meals get delivered. They will stay at home and let their food come to them.

The webs are true marvels of construction and consist of basically four types in this region. The cob web is an irregular series of threads that appear to have no order, but the spider moves about at ease. The sheet web is formed in a bowl or dome shape and is often found in shrubs and small trees. Funnels webs, looking like a sheet with a hole in the center, are common on the ground or at woods edge. And orb webs, in their circular fashion, are the ones that come to mind when we think of spider webs.

All are abundant now in the dew-covered mornings of late August. Because of their limited size and hidden structures, we are not likely to see the cob webs at this time. But others all hang with dew drops as the temperatures fall during the night. Walking as I do in the early mornings each day, I see a profusion of funnels webs (easily hundreds) in a mowed field. The swamps nearby have many sheet webs in tamaracks and marsh shrubs. These types of webs may last for days. It is the more delicate orb webs that are such a marvel to behold as they are laden with early-hour dew. Such webs are very photogenic, and it is interesting to note that even those who do not appreciate spiders consider a picture of these webs as a desired and coveted accomplishment.

In late August I like to take a web walk through a field to get immersed in these snares. Going east, toward the rising sun, I glimpse them in a backlit fashion. It is hard to comprehend how many there are. In a single walk in this field of only a few acres, I’m in the midst of hundreds of these constructions. Though there is some variation, most of these webs are made in the calm of dusk and remain open for business all night. Nocturnal hunting allows spiders to capture their main goal, moths, but also various flies, gnats and mosquitoes. The web is made of two kinds of thread. The non-sticky spokes (also called radii) go toward the center (the hub), while the sticky spirals circulate around the web, also toward the center. The spider waits in the hub or at the edge to pounce on any passing insect that gets stuck in the spirals. When we arrive in the morning, the hunting is usually finished and with dew in the webs, the spider has stepped aside.

The spider webs of late summer will be with us for several more weeks until the frost. Any walk (or morning commute) at dawn will give us much to delight in. Indeed, fences, signs and trees often hold a plethora of orbs.

Retired teacher Larry Weber is

the author of several books, including “Butterflies of the North Woods,” “Spiders of the North Woods” and “Webwood.” Contact him c/o

budgeteer@duluthbudgeteer.com.

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