While visiting Marblehead Lighthouse State Park recently, I checked out some boxwoods (Buxus spp.) given the proximity to Box Tree Moth (BTM) (Cydalima perspectalis, family Crambidae) infestations in Michigan. There’s speculation that BTM may have appeared in the New York counties bordering Lake Ontario after moths were blown across the lake from infestations near Toronto, Ontario.
Box Tree Moth Caterpillar in Loose Webbing
Some of the boxwoods had heavy webbing, with the tops entirely encased in silk. Although BTM caterpillars may envelope a small number of leaves with loose webbing, they never produce silk on the scale that I observed on the boxwoods in the state park.
Long-Jawed Spider Communal Web Boxwood – 1
Long-Jawed Spider Communal Web Boxwood - 2
There were no box tree moth caterpillars. A close examination revealed numerous elongated Long-Jawed Spiders (Tetragnatha spp., family Tetragnathidae) within the webbing, or resting on top of their mat-like silk creations. Their common name refers to their long chelicerae (fangs). Some species have chelicerae that are longer than the length of their cephalothorax, the part of the body where the legs attach.
The chelicerae have two parts that fold like a pocketknife. The “handle” part is thickened and has teeth-like spines lining the inner surface. The “blade” is like a fang. The names of the genus, Tetragnatha, and the family Tetragnathidae refer to the articulating chelicerae with “tetra-” derived from the Greek for “four,” and “-gnath” from the Greek “gnathos” for jaw.
Long-jawed spiders are also called “stretch spiders.” They have narrow bodies with extremely elongated abdomens. Their 1st, 2nd, and 4th pair of legs are long and slender, usually twice the length of the body. They commonly rest with their legs stretched forward, except for the 3rd set of legs, which are used to hang on. Their stretched appearance, coupled with mottled coloration, allows them to blend with their background.
Long-jawed spiders are sometimes called long-jawed orbweaver spiders. However, true orbweavers belong to the family Araneidae. Although long-jawed spiders can construct orb-shaped webs, their silk structures have fewer radial spokes.
Life in Spiderville
Long-jawed spiders may be found hiding out on various types of foliage, usually near water. For example, the image below shows a spider on an American lotus (Nelumbo lutea) leaf.
However, long-jawed spiders have a unique web-constructing behavior that’s rare for other spiders. They occasionally produce huge communal webs that envelop vegetation and look like something out of a sci-fi movie. Spiders are carnivorous and compete for meat, so they usually don’t get along. However, the communal long-jawed spider web-wonders may contain hundreds of individuals as well as a few other species, including free-loading orbweavers.
Long-Jawed Spider Communal Web Arborvitae
Research suggests that the availability of abundant prey triggers aggregations of long-jawed spiders. This may be one reason communal webs are most often observed near bodies of water that yield a bounty of aquatic insects such as midge flies and mayflies. Indeed, Marblehead Lighthouse State Park is located on the shores of Lake Erie.
In 2013, I photographed communal long-jawed spider webs that completely enveloped arborvitae in a property on the shores of Lake St. Clair just north of Detroit, MI. I don’t suffer from arachnophobia, but I saw the movie.
Long-Jawed Spider Communal Web Arborvitae – 1
Long-Jawed Spider Communal Web Arborvitae – 2
Thankfully, long-jawed spiders and their accompanying arachnid web groupies are not aggressive. They will scurry away when disturbed … unless you’re a meaty midge fly.
Funnels of Fate and Sheets to Slaughter
Don’t mistake the handiwork of Funnel Weavers (family Agelenidae) and Sheet Weavers (family Linyphiidae) for long-jawed spider webs. This is the time of the year when other common web-producing spiders found in Ohio begin to create Halloween-like webs.
Funnel weavers produce large, flat, sheet-like webs spun across the grass, under rocks or boards, or over the branches of shrubs such as yews and junipers. Funnel webs may measure more than 1' across. The web slopes gently towards a narrow funnel or tube where the spider resides awaiting its next victim.
Funnel Weaver Webs Highlighted with Dust
The medium-sized spiders resemble small wolf spiders. However, as with most spiders, they have excellent eyesight and will quickly scurry into their funnels if they spot arachnid-portrait photographers trying to snap a close-up (personal experience).
Sheet weavers construct several types of webs depending on the spider species. Some species spin flat or slightly curved webs that overlay vegetation and rival the sizes of webs spun by funnel weavers. However, there is no funnel included in the web architecture. The spiders hide beneath one edge of the web or inside plant foliage, along the edge of the web, to await their prey.
One of the more interesting sheet weavers is the Bowl-and-Doily Weaver (Frontinella communis). This is one of the few spider species with males capable of producing webs; however, females still dominate web weaving.
Bowl-and-Doily Weaver in the Morning Dew
Bowl-and-Doily Weaver Web Structure
The spider constructs a complex web structure consisting of distinctly bowl-shaped webbing suspended from plant stems by a crisscrossing array of silk threads; this is the "bowl" in the common name. The bowl is anchored below by a horizontal array of interwoven silk threads; the "doily." Flying insects drop into the web-bowl after bouncing in pinball fashion off the interlacing silk threads used to suspend the web. Of course, when they drop into the web-bowl, they fall into the "arms" (and fangs!) of the awaiting spider!
Bowl-and-Doily Weaver Web Structure
Selected References
Gillespie, R. G. (1987). The role of prey availability in aggregative behaviour of the orb weaving spider Tetragnatha elongata. Animal Behaviour, 35(3), 675-681.
https://doi.org/10.1016/S0003-3472(87)80103-3
Greene, A., Coddington, J. A., Breisch, N. L., De Roche, D. M., & Pagac Jr, B. B. (2010). An immense concentration of orb-weaving spiders with communal webbing in a man-made structural habitat. Am. Entomol, 56, 146-156.
https://doi.org/10.1093/ae/56.3.146
Adams, S. A., Gerbaulet, M., Schulz, S., Gillespie, R. G., & Uhl, G. (2021). Chemical species recognition in a Tetragnatha spider (Araneae: Tetragnathidae). Journal of Chemical Ecology, 47(1), 63-72.