Stretch Spiders

Long-Jawed Orb Weavers in the family Tetragnathidae, were first described in 1866 by a German entomologist named Anton Menge. This family name comes from the Greek words Tetra, and Gnathes, meaning four jaws. Which is an apt description for these odd spiders. The male and female both have large, elongated mouthparts. Which are exaggerated in size in comparison to their bodies to the point of being comical. Other common names attributed to this group of spiders is stretch spiders or stilt spiders, which seems a more apt descriptor. These spiders rest with their front and back legs stretched in front and behind their bodies giving them an extremely elongated appearance. This allows them to hide among grasses and other weedy plants without being seen. With hungry birds on the lookout for tasty spiders, this is a great way to keep out of sight. Sometimes these spiders wait in the center of the web or off to the side; camouflaged by their characteristic posture. If disturbed, they rush into the vegetation and wrap their legs around a blade of grass, or they drop to the ground. They are not particularly defensive and will try to remain hidden rather that seek confrontation. Like all spiders they have venom and have control over the amount delivered, dependent upon what the occasion calls for. The venom they possess is designed to subdue small prey items not to harm humans. However, because of their extremely large jaws, it could prove to be painful. Best to observe and not disturb.

This species is highly variable in appearance and may be creamy-yellow to greenish, on their underside is a thick black stripe with silvery bands on either side. Body length is approximately one inch, but with those long, outstretched legs they appear much larger.

There are nearly a thousand species within this family of spiders, with only fifteen known species in North America. Most are associated with tropical and sub-tropical climates. Several species are found in Missouri and one of the most common is the one pictured here called Tetragnatha extensa. I could not find a common name for this particular spider, but it is the one you are most likely to see near bodies of water such as lakes, ponds, and streams in our state. I find them frequently near ponds with their legs outstretched, hiding among the vegetation waiting for food to pass by. Like their cousins, the garden spiders we typically find in our gardens or hanging in the eaves of our homes, these spiders also spin orb webs. Their webs are more loosely woven than those of their cousins, with fewer spokes and an open hole in the center. Not nearly the works of art like the webs their cousins create. Nearly all orb weaver spiders rebuild their webs each evening. After a long night of insects bombarding the web, it sustains damage that makes catching the next day’s meal more difficult. Better to start the night off with a fresh web. In the case of long-jawed orb weavers their webs are tilted, sometimes in an almost-horizontal direction. How come? Because their webs are often situated over the water’s surface. There, insects like mayflies, midges, gnats, and caddisflies, which start their life as nymphs underwater, will emerge from the water as adults and fly directly up into the awaiting long-jawed spiders net.

 

Living near water not only provides the spider with supper, but it also provides vital humidity that keeps the spiders from desiccating or drying out. Temperature is the number one dehydrating factor more so than the humidity in the spider’s microhabitat, the spider can put up with a certain amount of dehydration if prey is plentiful. Meaning they will get most of their hydration from their prey. They also require weedy plants to camouflage themselves to avoid predation. They need access to open water, plenty of available prey, and suitable vegetation to anchor themselves to.

Most spiders are intolerant of neighboring spiders and often avoid building webs in close proximity of them. However, this particular group of spiders doesn’t seem to mind having neighbors and are often found in groups. The one pictured here was photographed near our pond, and there were many others in the area as well.

 

Like most spiders, mating occurs in late summer and is quite brief. Males and females lock jaws, this “lip-locked,” position means she cannot eat her mate. He uses his pedipalps to deliver his reproductive fluids to her, and a subsequent egg sac is then attached to nearby vegetation. Often the female will guard the eggs temporarily, but she is destined to die in a few weeks. The spiderlings will remain in the egg sac all winter and emerge the following spring.

These spiders are truly adapted to life near water, they build stringy webs near cattails and other aquatic vegetation and take advantage of emerging aquatic insects as a food source. If one should happen to fall into the water, no worries, they can walk on water. Provided of course they get a move on it before a hungry bass or frog makes a meal out of them.