Nature Watch: Gossamer Days

Author: Steve Ellis | 09/30/24

About the author: Steve Ellis is a naturalist and Land Trust member who enjoys sharing his love of the natural world. His blog series, “Nature Watch,” will appear each month in “Habitchat,” chronicling native plants and wildlife you can expect to see during that particular time of year. We thank Steve for sharing his passion, illustrating the importance of island conservation.

Overview

Travel any road in fall that parallels power lines and you’ll see disk-shaped spider webs outlined against the sky. The long, cool nights of September and October generate dew that bedecks the webs like glistening jewels. Circular webs are spun by a family of spiders known as orb weavers. These are the traditional webs many people associate with spiders. Fall’s dewy mornings give them the appearance of crocheted doilies.

There are many other spider web types including:

Funnel or triangular web. Built by grass spiders on the ground between places of cover such as rocks, this type of web takes several days to complete. While the silk is non-sticky, any insect encountering the web tumbles down the funnel to the waiting spider.
Tangle web. Anyone who has dealt with cobwebs is familiar with tangle webs. Cobwebs are simply disused tangles that have dust adhering to the silk. Tangle webs are three dimensional, shapeless jumbles of thread attached to multiple supports. Sticky droplets on the silk are broken by insects, entrapping them. Some tangle webs are constructed by multiple spiders.
Sheet web. This web is hammock-like and usually has a concave appearance. Horizontal threads are placed above the sheet to knock flying insects into the hammock. The spider usually waits upside-down for a victim to fall.
Woolly web. Perhaps the most interesting method for capturing insects is employed by spiders that spin woolly webs. These webs are haphazard in shape. The silk is thick-textured and electrostatically charged. An insect encountering the silk sticks to it in a process similar to cling wrap.

There are other specialty webs that serve a variety of purposes. Most are spun by females.

Not all spider species spin silken webs. Wolf, jumping and crab spiders hunt insects without the benefit of a web.

One behavior to look for in late summer and fall is ballooning. Young spiders, known as spiderlings, shoot out a length of silk called gossamer. The spiderlings are lifted off and drift away to find a territory of their own. At times, scores of silvery gossamers can be seen drifting through the air. In our yard in Coupeville this year, the gossamer days started in early September. The activity can continue through October.

Spiders consume large numbers of insects and are themselves preyed on by birds, amphibians, reptiles and large insects. The presence of spider webs is a sign of a healthy environment. With a little practice, a person can find examples of all these web types, thanks to the dew of fall.

Orb Weaver webs by Martha Ellis.

Fauna: Orb Weaver spiders (Araneidae species)

There are many orb weaver species in our area.

An orb weaver starts its web by shooting out a length of silk that attaches to something like a branch or powerline. It then crawls to the center and shoots out another line. A third line is dropped to form Y. Concentric rings are added to complete the orb or circle.

Most of the lines are non-sticky in order to be unseen by flying insects. Sticky capture lines, which can entrap victims, finish the web. The whole process can be completed as quickly as one hour. Juvenile orb weavers start out with small webs and increase the size as the season progresses.

Orb weavers are generally nocturnal, choosing to wait passively in the middle of the web during the day or off the web in some hiding spot. The latter individuals will have a trap line attached to the web that will alert them via vibrations through this line when an insect has been caught.

The spider wraps insect prey in silk for storage or consumes it on the spot. Harder parts such as wings or carapace are ejected in a ball.

Webs of orb weavers are repaired or rebuilt at night. Some species go so far as to eat the web and attached dew and use the ingested mix to spin new silk.

Males travel about looking for mates. Some females lay eggs in the fall, which overwinter and hatch in spring.

Nootka Rose by Martha Ellis.

Flora: Nootka Rose (Rosa nutkana)

This hardy shrub is highly successful, capable of forming dense thickets.

Nootka rose bushes are spindly and may reach a height of 9 feet. They sport large prickles at the base of each leaf, and the leaves themselves are divided into toothed leaflets.

Pink saucer-shaped blooms are open from May through July. Bumblebees, other bees and hummingbirds pollinate the large blossoms.

Rose hips measuring half to three-quarters of an inch in length follow pollination. These round to pear-shaped fruits add a splash of red to the landscape in fall and winter.

Many wildlife species use Nootka rose. Deer browse the young foliage, and chipmunks, sparrows and thrushes eat the hips.

Gall wasps use Nootka rose for reproduction, and this shrub is a host plant for mourning cloak and gray hairstreak butterflies. Small birds and mammals often take refuge in the safety of the rose thickets. The bushes are also routinely bedecked with spider webs.

Nootka rose can grow as part of the understory of our open forests but does best along roadsides, in clearings and above the shorelines.