KINGDOM: Animalia | PHYLUM: Arthropoda | CLASS: Arachnida | ORDER: Araneae | FAMILY: Linyphiidae (sheet-weaving spiders)

WHAT IS A SHEET-WEAVING SPIDER?
LIFE CYCLE
ECOLOGY
PEST STATUS
COMMON KENTUCKY SHEET-WEAVING SPIDERS
COLLECTING & PHOTOGRAPHY
SHEET-WEAVING SPIDER FACTS
MYTHS, LEGENDS, AND FOLKLORE

Sheet-Weaving Spiders, also known as Linyphiid spiders (from the scientific family name Linyphiidae) are small spiders (less than 1 centimeter long) with eight eyes that typically construct webs on or close to the ground. Some forest-dwelling species construct webs in trees using leaves or needles as support structures. They are very abundant throughout the Northern Hemisphere, but, because they are so small, many people do not know about them.

Linyphiid webs are not tidy spirals, like orb-webs, but are tangled networks of silken threads arranged in either a three-dimensional mass (a tangle web, very similar to a cob-web, but usually smaller) or a two-dimensional sheet (a sheet web). Unlike orb-weavers, many linyphiids do not use sticky silk in their webs. This means that their webs either ensnare prey by tangling it up; or allow the spider to find their prey by vibrations in the web without actually ensnaring the prey at all.

Male and female linyphiid spiders can be differentiated by size (males are usually somewhat smaller and more slender than females) and by their palps (extra limbs near the spider’s mouth). Female palps are small and thin. Male palps end in large, bulbous extensions that they use for mating.

Most linyphiids probably live only one year. Many may even live for only a few months. Eggs are laid in silken sacs in the web or hiding in leaf litter on the ground. There can be just a few, or many dozen eggs in a single egg sac, depending on species and individual. Like all spiders, linyphiids develop through simple metamorphosis: spiderlings look like tiny adult spiders (but with lighter coloration), and shed their outer skin in order to grow.

Some species mate and lay eggs throughout the year, while others have more discreet mating seasons. Both eggs and adults have been known to overwinter, and some species may even build webs to catch prey in the cold winter months.

Linyphiid spiders are among the most common types of arthropod predators in crop fields. Webs can be attached to trees, grass, fenceposts, leaf litter or even just on the soil. There are many insects and other arthropods in the soil (such as springtails) that these spiders can consume. They will also eat flies, aphids, leafhoppers, other spiders, and tiny wasps.

Linyphiid spiders will build their webs at night (sometimes taking several consecutive nights to complete the web), and will stay at one web location for several days or even longer. Because their webs are more “expensive” than orb-webs in terms of the amount of silk used, they do not change web-sites as frequently.

Linyphiid spiders are also known to balloon regularly. A ballooning spider extends a long line of silk from its spinnerets, and floats away when the wind catches the line. This allows them to move rapidly across long distances, sometimes even thousands of miles! Although many kinds of spiders balloon, linyphiids are thought to balloon much more regularly. Furthermore, whereas usually only immatures of other spiders balloon regularly, adult linyphiids will readily balloon as well.

Linyphiid spiders are not considered pests. They are not known to bite people. They feed on many agricultural pests, such as aphids and leafhoppers, and they are common in many crop fields, so they may actually be beneficial for farmers.

Tennesseellum formicum
GENUS and SPECIES: Tennesseellum formicum
One of Kentucky's most common spiders is a sheet-weaver called Tennesseellum formicum. This spider is about 2 millimeters long. It can be found in grass, leaf litter or crops, and it tends to prefer disturbed habitats (such as crops that are harvested or mowed regularly), bare ground or patchy vegetation. Its webs are often 5–6 centimeters in diameter. It can be found throughout the spring and summer.

Erigone autumnalis
GENUS and SPECIES: Erigone autumnalis
Kentucky is home to a very, very tiny spider called Erigone autumnalis. This spider is usually 1 or 1.5 millimeters long. Its tangled webs are also very tiny, often no bigger than a quarter. It can be found in leaf litter and on bare soil. E. autumnalis can be found throughout the year (even sometimes in winter). This spider is unique in that the male spiders are larger than the female spiders.

Grammonota inornata
GENUS and SPECIES: Grammonota inornata
Although Grammonota inornata is a close relative of E. autumnalis (above), it is much larger (although, at 3 mm, it’s still a very small animal). It builds tangle webs and sheet webs, with a diameter of 3–4 cm, and a height of about 1 cm and often places them at the very base of a plant stem. It is active throughout the spring and summer.

Florinda coccinea
GENUS and SPECIES: Florinda coccinea
Sometimes called the “red grass spider,” because of its bright color, this spider is quite large for a linyphiid (5–6 mm), and is easily spotted. It can be recognized by the black tubercle (bump) at the end of its abdomen (smaller picture, arrow). It builds webs in grass, usually a few centimeters off the ground. The web is a sheet about 10 centimeters across, but with a large tangle above the sheet to knock down any passing flies into the sheet below. Florinda is most common in late summer, especially August.

Pityohyphantes costatus
GENUS and SPECIES: Pityohyphantes costatus
These spiders are commonly called “hammock spiders” and are some of the largest linyphiids in North America. Typically adults are 6-7mm in length, but some specimens have been as large as 9mm. In Kentucky, these have been collected on hemlock trees. It builds its webs in lower branches of trees, on shrubs and fences, forming a large flat sheet with a small barrier web built above the sheet. It is active in spring and early summer as adults. An interesting fact about this species is that it hibernates or overwinters under loose bark and stones as adults or penultimate instars (the last stage before adulthood).

Frontinella pyramitela
GENUS and SPECIES: Frontinella pyramitela
These spiders are commonly called “bowl and doily spiders” and build neatly crafted webs. The webs consist of a bowl-shaped cup and underneath this is a flat, typically horizontal sheet. Sometimes above the bowl it weaves a maze of tangled web. Insects fall into this bowl and it captures its prey by pulling it through the flat sheet below. You can find this spider usually in coniferous woods on lower branches or in bushes and tall grass. This species is active in spring through mid summer. Some interesting facts about this species is that adult males and females will usually share the same web as a pair. Frontinella spiderlings are also known for their ballooning capabilities – going great distances and elevations.

Since they are so small, linyphiid spiders can be a challenge for collectors and photographers. However, they can be found in virtually any habitat: grass, leaf litter and crop fields are good places to look. They are most easily located on dewy mornings when moisture droplets cling to the spiders’ webs. These conditions can be artificially created by using a misting bottle, which makes their webs visible by coating it with reflective water droplets. This helps in finding spiders and in photographing webs. Linyphiids should be preserved in alcohol, like all spiders.

The bits of gossamer that occasionally fall out of the sky are often the remnants of linyphiid webs that were carried away by rising air currents on warm mornings.

In the United Kingdom, linyphiid spiders are called “money spiders,” because of the popular superstition that, if you find one on your hand or in your hair, it has come to bring you gifts or spin you new clothes. Often, people would spin the spider around their heads on the end of a thread to secure the good luck. It is considered bad luck to kill a money spider.

Do you know any myths, legends, or folklore about sheet-weaving spiders? If so, let us know.