Yesterday I awoke to a cool and foggy morning in Gloucester. Until the sun rose to burn it off, the river was shrouded in a thick cloud of moisture, a haze that left the landscape laden in a covering of morning dew. This heavy dew is a frequent occurrence in the fall in Tidewater and it’s a perfect time to check out the almost invisible world of miniature spiders.
There are hundreds of sheet web spiders (Linyphiidae) but one tiny sheet web spider interests me most. The Bowl and Doily Spider (Frontinella communis), found everywhere in the Eastern US, goes unnoticed on a dry day. Just take a look at what we can see on a dew laden morning.
These tiny webs are named for the unique shapes that the spider weaves. There are two levels to the web, an non-sticky upper area known as the bowl and a lower area called the doily. The spider that lives in the web is found underneath the bowl upside down. Entomologists believe the doily is to protect the spider from enemies below and the bowl may protect it from above. There are ‘trap lines’ that connect all parts of the web to the plants. Although I’ve never seen an insect trapped in the bowl, it’s been said that the Bowl and Doily Spider will bite an insect through this web, then it wraps the prey (mosquitoes, gnats, small flies, aphids) in silk.
I often lean close trying to spot the spider between the sheets of web. But I think I must disturb a trap line and the spider disappears before I can focus my eyes or a camera. We’re talking about a web of three or four inches and a spider about 4 mm in length.
However, I did get lucky this time and captured a fuzzy photo before the little one scampered away.
In areas of Maine, the native Bowl and Doily Spider is under threat from an extremely aggressive European spider, the Palearctic spider (L. triangularis) that was accidentally introduced into the US. It is overtaking the webs of several varieties of sheet web spiders. The dominant L. triangularis is leading to a decline in spider biodiversity in areas of Arcadia National Park. No one can predict what will happen, but lets hope those aggressive invaders don’t like the climate in Virginia.
Ann Hohenberger, The Garden Club of Virginia