There is a kleptoparasite in your web!

Up against a window and near the edge of our back deck I found a beautiful orb web and one of my favorite spiders in residence.  It was a Orchard Orbweaver (Leucauge venusta).  She is one of the few green spiders in Ohio, and is also famous for the iridescent silver reflective patches on her abdomen.

An Orchard Orbweaver (Leucauge venusta) in her web

An Orchard Orbweaver (Leucauge venusta) in her web

As I leaned over to admire her, I noticed that there was a second spider hanging in among a few strands of slik slung below the orb of the Orchard Spider’s web. I recognized this spider by her distinctive triangular body shape.  It was an adult female Neospintharus trigonum (aka Argyrodes trigonum).

I felt like yelling to the Orchard Orbweaver the warning “There is a kleptoparasite in your web!” but she probably wouldn’t have understood.  Neospintharus is infamous as a “web invader.”  They add a few strands of silk to, or near an occupied spider web.  Then they wait until the resident spider captures prey.  If the resident is already busy with another prey item, or for some reason doesn’t notice the new potential prey, the Neospintharus sneaks into the web, cuts the prey free, and consumes it herself.  This is a mooch behavior given the technical name “kleptoparasitism” based on parasitic theft.

Here are a couple of views of the thief, inches away from the resident.

A Neospintharus trigonum female in a silk tangle below the web of an orchard orbweaver (Leucauge venusta).

A Neospintharus trigonum female in a silk tangle below the web of an orchard orbweaver (Leucauge venusta).

A Neospintharus trigonum female in a silk tangle below the web of an orchard orbweaver (Leucauge venusta).

A Neospintharus trigonum female in a silk tangle below the web of an orchard orbweaver (Leucauge venusta).

In this case crime did pay, because the Neospintharus had evidently captured enough prey to develop and lay a clutch of eggs.  Her beautiful inverted-urn shaped egg case was attached to the lower end of her little tangle near the window screen.

An egg case of Neospintharus trigonum

An egg case of Neospintharus trigonum

Here is another photo of the distinctive egg case of another Neospintharus trigonum.

photo of egg cases of Neospintharus trigonum

Neospintharus trigonum egg cases

Sometimes Neospintharus isn’t so passive.  They occasionally attack the resident spider, eat her, and then take possession of the web.  When they do this they eventually replace the original web with a three-dimensional tangle of their own making.

When they are inactive, Neospintharus trigonum can look very un-spiderlike. They fold up their legs agains their body and hang in the web looking more like a triangular bit of leaf or seed pod.

photo of Neospintharus trigonum

Neospintharus trigonum female

Here is a different female with her egg case.

Neospintharus trigonum with her egg case

In the current case, either the Orchard Orbweaver was too big to attack, or perhaps there was enough prey for both.

Hypsosinga in a web!

In early June I had a surprise in our yard.  For the first time I found a Hypsosinga rubens in her web.  This is a relatively small and rarely-encountered species.  The range of the species includes most of the eastern half of North America north of Mexico as well as the prairie provinces of Canada, but few individuals are ever noticed.  Almost all the records for the species are obtained in general sweep net samples of fields and field-edges.  In his review of this and related genera, Herbert Levi also mentions that some have been obtained from leaf litter samples (Levi, 1971).  Nicholas Marcellus Hentz in his iconic monograph “Spiders of the United States” writes in 1875 that “This species is not rare, both sexes having been found on perpendicular webs.”  During the Ohio Spider Survey (1994-2014) only four males, five females, and two immatures were collected.

The most remarkable thing about the adult female Hypsosinga rubens that I found on June 6th was that she was in an orb web oriented horizontally.  This is very unusual for members of the family Araneidae (orbweavers).  Horizontal webs are typical of a different family, the long-jawed orbweavers (Tetragnathidae).  In addition to the typical horizontal webs, some members of that family build their webs at an oblique angle, like those of the common orchard orbweaver (Leucauge venusta). Orchard orbweavers are common and familiar, as well as spectacular because of their bright green and iridescent silver coloration.  Finding a “typical” orbweaver in a horizontal web was a shock to me.  And remember that Hentz states that this species builds a “perpendicular” web.  This was my first observation of an undisturbed individual resting in her web.

Hypsosinga rubens female in a horizontal web, viewed from above

Hypsosinga rubens female in her web

Hypsosinga rubens  adult female in her web

As you can see from these photos, this is no plain Jane spider! She is bright red-orange and black.  Even at her diminutive size (body length about 3/16 inches) the dramatic coloration is striking.  Her web was stretched across the upper leaf tips of a gray-headed coneflower (Ratibida pinnata).

I admit to being surprised by how brightly colored some of Ohio’s day-active spiders are!  Surely they would be conspicuous to any predator armed with color vision.  How they avoid becoming prey is a mystery to me.  Here is another photo of her hanging below her web.

Hypsosinga rubens female in her web from below

Because there are several species in the genus Hypsosinga, and each is quite variable in color, I captured this individual and examined her under a microscope.  She was an adult female.  Here she is in captivity after being anesthetized with CO2.

Hypsosinga rubens female dark form in captivity

Hypsosinga rubens female (dark form) in captivity

So you could be excused for wondering, why is Rich writing a blog post about one spider in his yard?  The reason is that six days later I found a second individual of the same beautiful species.  She was in a proper vertical orb web, suspended among the foliate of an orchid plant on my back deck.  And she was a completely different color form!

Hypsosinga rubens female light form in her web

Hypsosinga rubens female (light form) in her vertical web

Here is what she looked like in captivity, you can see that this “light form” has very different coloration. Under the scope her reproductive anatomy was identical to the dark form individual I’d seen a week earlier.

Hypsosinga rubens female light form in captivity

Hypsosinga rubens female (light form) in captivity

Having found my second ever observation of this spider in a natural undisturbed pose would be enough to be exciting.  But if you look at the original photo of her in her web you might notice something else unusual, she is oriented with her head (cephalothorax) uppermost!  Almost all orb-weaving spiders hang head down.  The only other orbweaver species in our area that I’m aware of that habitually hangs in the web head-up is the triangulate orbweaver (Verrucosa arenata).

Triangulate orbweavers are also polymorphic and often very brightly colored.  They too have often been found out in the middle of their webs during the day.  Are these brightly colored, day-active spiders distasteful?  Are they advertising their bad taste with aposematic coloration?  As far as I know there is no evidence one way or the other regarding this possibility.  Here is a photo of a triangulate orbweaver in her web.

triangulate orbweaver (Verrucosa arenata) hanging in her web, head up.

triangulate orbweaver (Verrucosa arenata) hanging in her web, head up.

Not all triangulate orbweavers are as “plain” as this individual. Check out this remarkable color form in a photo taken by Chris Friesen in his yard near Delaware Ohio back in October of 2016.

triangulate orbweaver, red form, female

triangulate orbweaver (Verrucosa arenata), red form, female

If you can avert your gaze from that spectacular spider, notice that she has captured and wrapped a wasp prey item.  So she is no slacker at dealing with formidable predatory arthropods!

One other feature of the understudied biology of Hypsosinga rubens is highlighted by Herbert Levi in his review. He speculates that spiders in this genus “make a complete orb probably with a retreat.”  Neither of the females in my yard had any sort of retreat associated or near the web.  The 12 June female used the “drop and hide” method of reacting to my close approach. It tested my patience to wait until she climbed back up her “safety line” to her web after she dropped. This behavior is typical of orbweavers that do not build a retreat.

As far as I’m aware these are the first descriptions of the webs of Hypsosinga rubens since Hentz’s “perpendicular” comment in 1875. The posture (head up) is very unusual. These casual observations highlight how much we don’t know about our spiders. This species represents the 190th found in our yard, a small (1.3 acre) lot in a primarily agricultural landscape. The remarkable spider diversity here is partly the result of our extensive native plantings, but I’m guessing it is also a reflection of having residents (Amy and I) that are keenly interested in the biota here, and paying attention for the past 28 years.

Winter spiders (yes they are out there)

In central Ohio where I live, the winter is a time of rest for many animals.  They seek shelter from the cold weather and hunker down.  Some large animals hibernate, many smaller ones become inactive, in a sort of torpor that is less long-lasting. If there is a “break” in the cold they can become active relatively quickly.  Among the arthropods, there are many insects that enter a state called diapause.  In this physiological state they literally pause their normal development and delay progression into the next phase of their life cycle (adulthood for example).  Our Ohio spiders pass the winter in almost every possible condition.

Shale Hollow Park, Delaware County, Ohio 8Dec2013

Shale Hollow Park, Delaware County, Ohio 8Dec2013

In some species the adult female builds an egg case and lays the eggs in the fall. She will often stay with the egg case, guarding it from potential harm (mostly by parasitic insects, such as wasps).  She may die there, or somewhere nearby. For these species the population in winter exists as scattered egg cases, under logs, in the leaf litter, cracks in the soil, or under the bark of trees and shrubs.

decomposing log at Highbanks Metropark, Delaware County, Ohio

decomposing log at Highbanks Metropark, Delaware County, Ohio

A few species are “hardy” and survive through the winter as full-sized adults.  These adults usually select a hidden retreat.  Many of these spiders construct a silken sac and spend the winter ensconced there.  Below are photos of a few such species.

adult male Amaurobius ferox

adult male Amaurobius ferox

adult male Cicurina pallida

adult male Cicurina pallida

adult male Wadotes calcaratus

adult male Wadotes calcaratus

In my experience these spiders are often located by searching under logs lying on the ground, the older and more thoroughly decomposed the better.  Before exploring this sort of habitat it is important to realize that by turning the log you are exposing the residents there to a hostile environment, dryer, often colder, than before the log was moved.  So do this sparingly, only if you have a good reason, and always return the log as close as possible to the position it was in before you began your exploration.

adult female Centromerus cornupalpis

adult female Centromerus cornupalpis

A majority of the spiders found in the winter will be immature.  Some of these developed through the summer and autumn and are nearly mature.  The ones which are in their last immature instar are referred to as “sub-adult” because after one more molt they will become mature, reproductively capable, adults.  The males of these subadult spiders often show expanded palps, but they are smooth-looking.  These can easily be distinguished from the mature males’ palps which typically have a much darker coloration and many visible angular, bulging, or complex-shaped structures.  Here is one example of a sub-adult male sac spider.

subadult male Clubiona sp?

subadult male Clubiona sp? with arrow indicating the smooth developing palp

This is a photo (below) of what is probably the same species after achieving adulthood. Note the difference in the appearance of the palps. The body is also a different color, but some of that difference is just individual variation.

adult male Clubiona abboti

adult male Clubiona abboti with arrows indicating the mature palps

Many of the spiders that I have found in the winter were living among the layers of fallen leaves on the forest floor.  This material is referred to as “leaf litter” and is the key building block material of developing forest soil.  For organisms living on the ground stratum, the falling leaves in autumn constitute a major input of energy (think stored chemical energy in the dead leaf tissues).  This material (dead logs, fallen twigs, bark, and leaves) becomes food for a wide variety of fungi and bacteria.  A large number of tiny animals feed on the fungi and bacteria including springtails (order Collembola) and a great variety of mites.  Such critters are prime food for tiny spiders living in the same areas.

This amazing soil community is often at its peak of abundance and diversity in the late winter.  Think of those falling leaves of autumn as similar to the spring flush of growth, but the growth in this case is of decomposers and the organisms that feed on them.  Some tiny spiders, such as those in the sheet weaver family (Linyphiidae) are mature and even court and mate during this time.  They live in the upper layers of soil, hidden under the leaves, and sometimes snow.  To study these communities, biologists often sample the leaf litter as you can see in this photo.  What you can’t see in the photo is a large plastic garbage bag for the sample. The “tote” is a convenient way to carry this plastic bag.

RAB collecting litter at Johnson Woods Nature Preserve, Wayne County, Ohio

RAB collecting litter at Johnson Woods Nature Preserve, Wayne County, Ohio

After collecting the litter, it is placed in a device referred to as a Berlese funnel.  The name is in honor of the Italian entomologist Antonio Berlese (1863-1927) who invented the basic technique.  Later modified by the Swedish entomologist/arachnologist Hugo Albert Tullgren (1874-1958) who introduced the use of a light bulb for the source of heat.  Basically the leaf litter or soil sample is placed in a large funnel over a screen.  In modern apparatus a light is suspended above the sample.  As the leaves and soil heat up and dry out, the organisms living there migrate down to the bottom of the sample and drop through the funnel into a collecting container.  These samples can be very rich.

Here are some of the sheet weaving spiders (family Linyphiidae) that I have found in leaf litter during the winter months.

adult female Hypselistes florens

adult female Hypselistes florens

adult male Idionella formosa

adult male Idionella formosa

adult male Lepthyphantes leprosus

adult male Lepthyphantes leprosus

adult female Grammonota inornata

adult female Grammonota inornata

adult male Grammonota inornata

adult male Grammonota inornata

adult female Gonatium crassipalpum

adult female Gonatium crassipalpum

adult male Gonatium crassipalpum

adult male Gonatium crassipalpum

These are really small animals, even as adults.  Here are a few shots with familiar objects included in the photos for scale.

adult female Islandiana flaveola posed on a pencil tip

 

adult male linyphiid on a pencil

adult male linyphiid on a pencil

 

adult male Agyneta micaria with quarter for scale

adult male Agyneta micaria with quarter for scale

Other spiders spend the winter as tiny juveniles.  One example is this little immature Drassyllus sp? (family Gnaphosidae, the stealthy ground spiders).  It is very pale in color, not unusual in juvenile spiders.

immature Drassyllus sp? on a penny

immature Drassyllus sp? on a penny

It will grow up during the following spring or summer to be a ground dwelling predator that is very dark in color.  Here is an adult male Drassyllus depressus, one member of the genus to which this little spider belongs. He (the adult) isn’t a huge spider either, having a total body length (without legs) of about 5 mm (3/16 inch).

adult male Drassyllus depressus

adult male Drassyllus depressus

The next time you step into the woods for a winter walk, consider that you are probably surrounded by a busy community of organisms living hidden away from view.  These winter spiders may not be as obvious as the beautiful orb-weavers of the summer, but they are vital links in the food web.

Life among the galls

During the early summer back in 2015 I found that a few leaves of my backyard grape vines were covered with colorful galls.  After some research, I identified these galls as “grape tube galls” which were likely created by Cecidomyia viticola (AKA Schizomyia viticola) a tiny fly.  The gall growth is stimulated by the developing fly larva within the plant tissue.  Some species cause significant damage to the host plant, but in this case only a few leaves were affected, and any damage to my grape vine was insignificant.  In my opinion the galls were very beautiful.

photo of grape leaf with tube galls

A grape leaf with tube galls likely produced by a fly Cecidomyia viticola

As I was admiring the galls, a small flower fly (Syrphidae) landed on the edge of the leaf.

photo of grape leaf with tube galls

A grape leaf with tube galls likely produced by a fly Cecidomyia viticola with a flower fly (family Syrphidae) on edge of leaf (not the gall maker)

When I bent down to examine the tubes closely, I found spiders among the galls!

photo of mesweavers under webbing

pair of meshweavers under thin webbing among tube galls

Some small spiders build their webs in the spaces created by curved leaves.  In this case, hiding below the thin whispy webbing stretched between the tube galls on my grape leaves were tiny brownish spiders.  I recognized them as meshweavers (family Dictynidae).  There are two species of meshweavers in my yard that I have found building very thin webs on the surfaces of leaves.  These two species Dictyna foliacea and Emblyna sublata are quite similar in appearance.  They are both small brownish spiders, in the females there is a light yellowish or orange colored folium (central stripe) on the abdomen.  One way to distinguish these females is a difference in the markings on the cephalothorax (head region). In Dictyna foliacea there is usually a single stripe of white hairs, in Emblyna sublata there are usually three separate white stripes of white hairs (sometimes more).

Both of these two species of meshweaver females are illustrated in my book (Plate 21) and I include those paintings by Steve Buchanan below.

painting of Dictyna foliacea and Emblyna sublata

comparison of female meshweavers Dictyna foliacea and Emblyna sublata paintings by Steve Buchanan

In this situation among the galls the residents were a pair of tiny meshweavers (Dictyna foliacea).  This spider seems to prefer the leaves of herbaceous plants in fields and brushy areas.  I usually encounter them on the upper surfaces of goldenrod or other plants in our home prairie patch.  The grape leaves with tube galls provided a convenient substrate for their web.

photo of pair of meshweavers in their web

pair of meshweavers (Dictyna foliacea) in their web between grape tube galls

Perhaps the flash from my camera, or the fact that I was hovering very close to the leaf, stimulated the spiders to move.  Here are photos of the male, and the female after they moved at least a bit more into the open.

photo of male meshweaver (Dictyna foliacea)

male meshweaver (Dictyna foliacea) in web

photo of female meshweaver

female meshweaver (Dictyna foliacea) at the edge of her web among grape tube galls

Here (below) is a photo of the similar looking meshweaver Emblyna sublata in her web atop a leaf.  These photos were taken during a bio-blitz in May of 2015 at a nearby park (Shale Hollow Park).  Notice that she has more white hairs on her cephalothorax (head region) than Dictyna foliacea.

photo of typical form female meshweaver

typical form female of the meshweaver Emblyna sublata, scale bar 1/8 ” (appx 3mm)

Here (below) is another individual of Emblyna sublata photographed on at the same location and time as the photograph above.  She is an extremely dark colored individual with a very fat abdomen (probably full of developing eggs). She is busy eating.

photo of dark form female meshweaver

dark form female of the meshweaver Emblyna sublata eating a prey item

Here is another photograph taken on the same day showing another pair, male and female meshweavers (Emblyna sublata) in their nuptial web.

photo of pair of meshweavers Emblyna sublata

pair of meshweavers (Emblyna sublata), male below looking up at female above him

In many cases, pairs of spiders have been found cohabiting the space under the web.  On one occasion while wandering in my yard I found a male with a fly prey. By the time I returned with my camera, the fly had been transferred to the female. Perhaps the male offered her the fly as a nuptial gift.  This sort of behavior is known for some spiders, but I was unaware that meshweaver males provided nuptial gifts.  Or perhaps the larger female just stole the fly from the male.

photo of pair of meshweavers on leaf

pair of meshweavers (Dictyna foliacea) in thin web on top surface of a goldenrod leaf in my back yard, here the male is on the left and the female is feeding on a fly prey

A slightly closer view of the same pair.

photo of pair of meshweavers on leaf

pair of meshweavers (Dictyna foliacea) in thin web on top surface of goldenrod leaf, female with fly prey

Even tiny meshweavers such as these can sometimes capture prey that seem huge in comparison to the spider.  On June 17, 2008 I found a female meshweaver (Emblyna sublata) with a fly that was very much larger than the spider.

photo of mesweaver with large fly prey

meshweaver (Emblyna sublata) feeding on a large prey item (fly)

In this case she has bitten the fly near the base of the antennae, maybe this is because there is soft flexible cuticle on the fly at this position; making it easier for the tiny fangs of the spider to penetrate the exoskeleton of  the fly. Here is a closer view.

photo of meshweaver with large prey (fly)

close view of a female meshweaver (Emblyna sublata) with a huge prey (fly)

There always seems to be something going on in our small back yard, all I need to do is to slow down and pay attention.  As I write this post it is winter, but I can still recall that early summer morning, when finding colorful galls on the leaves of my grape vines led me to an adventure observing meshweavers.

Common Names

For many, one of the most frustrating things about observing spiders is the fact that most species are not referred to by “common names.”  These easy to remember English names have been given to all bird species, butterfly species, as well as many other creatures familiar to us.

Only a few spiders have been given such names. There is actually an official committee (Committee on Common Names of Arachnids of the American Arachnological Society) that was created to provide standardized English names for species of arachnids of medical or economic importance, or those common enough to be familiar.  Anyone who has given a talk on spiders to a general audience will immediately recognize the value of common names.  Trust me, I’ve given more than my share of programs punctuated by names such as “Parasteatoda tepidariorum” or “Agelenopsis pennsylvanica.”

Most spider species are tiny and inconspicuous. Well over half of the described species in North America north of Mexico never achieve a body length greater than 2 or 3 mm (~1/16 – 1/8 inch).  These little spiders are so difficult to see well that, even if we gave them descriptive English names, the features implicit in the name would be too inconspicuous to notice. They simply wouldn’t be useful, even for experienced naturalists.

But, as the existence of the aforementioned committee implies, some spiders do have useful  English names that are commonly used.  Here are a few examples.

The bowl-and-doily spider is the first spider common name that many of us learned. The phrase bowl-and-doily refers the iconic web of this species.  It does indeed have a bowl shaped sheet web, suspended over a relatively flat lacy sheet web.

the web of a bowl and doily spider

the web of a bowl and doily spider

There is actually more to this web than the obvious bowl and doily. There is also a non-sticky tangle above the bowl.  The purpose of the tangle is to intercept the flight of potential prey. When a hapless fly blunders into the tangle, it is often knocked out of the air and tumbles down to the surface of the bowl.  The vibrations of this motion are detected by the resident spider and she is usually waiting just below the bowl precisely where the fly lands.  In a flash she strikes up through the silk web and envenomates the fly.  This is not a fair contest and the fly is quickly killed and drawn through the bowl to provide a feast for the resident spider. Here is another photo of such a web taken on a particularly dewy morning that reveals the tangle above the bowl.

the web of a bowl and doily spider showing the tangle of threads above the bowl

the web of a bowl and doily spider showing the tangle of threads above the bowl

The resident spider is relatively small.  She is most often found hanging below the web.  Her dark coloration with white bands is actually somewhat cryptic in this situation.

female bowl and doily spider (Frontinella communis) hanging under her bowl ready for action

female bowl and doily spider (Frontinella communis) hanging under her bowl ready for action

For a close-up view, here is an illustration of her from Common Spiders of North America drawn by Steve Buchanan.

female bowl and doily spider (Frontinella communis) illustration by Steve Buchanan

female bowl and doily spider (Frontinella communis) illustration by Steve Buchanan

If you are lucky enough to encounter a courting pair, the male often stands out in contrasting reddish coloration.  The following beautiful photo was made by Sarah Rose.  In this case the red male is closest to us with his potential mate in the back.

A pair of bowl and doily spiders, red male in front, by Sarah J. Rose

A pair of bowl and doily spiders, red male in front, by Sarah J. Rose

So why the quaint name “bowl and doily?”  This is actually a fairly old common name. It dates to a time when finding a bowl of candy sitting on top of a crocheted doily would have been commonplace in your grandmother’s parlor. The name is based on the fancied resemblance of the web to this scene. I staged this “re-creation” below.

"staged" bowl-and-doily meant to evoke domestic history

“staged” bowl-and-doily meant to evoke domestic history

Here is another example of a common name based on a distinctive web.  The filmy dome spider (Neriene radiata).  Her web is usually built in the forest, often in the shady understory.  The web is composed of very fine silk strands and is quite delicate.  It can be difficult to see the web at all.  But when there is enough dew condensation the dome shaped sheet is revealed.

web of a filmy dome spider

web of a filmy dome spider

Here is a more dramatic photo by Alan Knowles. He found the spider on a very dewy morning and photographed it with a flash. You can see (if you look closely) that the spider is resting under her dome near the top at the left side.

Alan Knowles photo (scanned) of a filmy dome spider in her dewy web enhanced by flash

Alan Knowles photo (scanned) of a filmy dome spider in her dewy web enhanced by flash

Here is the illustration from B.J. Kaston’s classic How to Know the Spiders.  It reveals not only the dome but also the tangle of knock-down strands above the web.

illustration of a filmy dome spider's web, from B.J. Kaston's How to Know the Spiders

illustration of a filmy dome spider’s web, from B.J. Kaston’s How to Know the Spiders

The occupant of this beautiful delicate web is another small sheet-weaving species Neriene radiata.  The sharp-eyed reader will notice that the species scientific name has changed since B.J. Kaston’s book was first published (1953, 1972).  Here is a female filmy dome spider hanging in her (invisible) web.

female filmy dome spider (Neriene radiata) hanging in her nearly invisible web, finishing her meal

female filmy dome spider (Neriene radiata) hanging in her nearly invisible web, finishing her meal

And here is another photo made by Sarah J. Rose of a pair sharing a dome.

A pair of filmy dome spiders, male on left, by Sarah J. Rose

A pair of filmy dome spiders, male on left, by Sarah J. Rose

When the pair come together to mate the male reaches out with his palp and transfers sperm into her gonopore on the ventral side (at the top in this pose) of her abdomen.  In this photo you can see the expanded hematodocha at the tip of his palp. The fluid that inflates this bag-like structure is not the semen. It is actually hemolymph fluid (blood) and the pressure from this inflated sac squeezes the actual semen out of its reservoir and into the female.

pair of filmy dome spiders mating, note the expanded hematodocha of the male

pair of filmy dome spiders mating, note the expanded hematodocha of the male

Here is a close up illustration of a female filmy dome spider from Common Spiders of North America.

female filmy dome spider (Neriene radiata) illustration by Steve Buchanan

female filmy dome spider (Neriene radiata) illustration by Steve Buchanan

Here is a third sheet-weaver example of a common name derived from the web structure built by the spider.  This one is called the hammock spider based on a fanciful interpretation of the sagging sheet suspended from branches at the edges.  I’ll include a photo of a web and also a real hammock for comparison, you be the judge.

web of a hammock spider (Pityohyphantes costatus)

web of a hammock spider (Pityohyphantes costatus)

cotton fiber hammock

cotton fiber hammock

The hammock spider is quite a bit larger than either of the others described above. She is a striking spiny-legged spider with a distinctive jagged dark band down the middle of her abdomen. and a dark central mark on the top of her cephalothorax that splits into two lines near the eyes.

hammock spider (Pityohyphantes costatus) female eating a prey item in a retreat under a culvert at the edge of her web

hammock spider (Pityohyphantes costatus) female eating a prey item in a retreat under a culvert at the edge of her web

hammock spider (Pityohyphantes costatus) in her web that has been thoroughly coated with dust motes

hammock spider (Pityohyphantes costatus) in her web that has been thoroughly coated with dust motes

Another close up from Common Spiders of North America.

female hammock spider (Pityohyphantes costatus) illustration by Steve Buchanan

female hammock spider (Pityohyphantes costatus) illustration by Steve Buchanan

Early in the spring (at the time I’m writing this) the hammock spiders are usually hiding in a loose silken retreat under a leaf.  These individuals are often sub-adult (one molt away from maturity).  With the arrival of truly warm days they will construct their webs, perhaps capture a few insects and then molt into the adult.  I’ve captured adult females in Ohio between late May and mid September.  Most of the individuals I encounter in the late autumn, winter, and early spring, are immatures.

My last example of a spider with a common name based on a web is the lattice orbweaver (Araneus thaddeus). This spider is normally hidden from view.  They hide in a tightly folded leaf retreat. The entrance to the retreat is a tubular silken structure with walls that appear a lot like the criss-cross pattern found in lattice work.  In this first photo you can see the orb itself, which is connected to the retreat by a “signal lines” which transmit vibrations to the spider. If she detects that a prey has been captured in the orb, she rushes out to grab a meal.

the orb web of a lattice orbweaver (Araneus thaddeus)

the orb web of a lattice orbweaver (Araneus thaddeus)

The spider is waiting well back in the retreat.

female lattice orbweaver (Araneus thaddeus) finishing a meal in her retreat

female lattice orbweaver (Araneus thaddeus) finishing a meal in her retreat

Here is a shot of the signature “lattice” of the retreat entrance tube.

the lattice-like retreat tube of a lattice orbweaver

the lattice-like retreat tube of a lattice orbweaver

Maybe it takes a bit of imagination, but I can see a resemblance to a garden lattice.

a garden lattice

a garden lattice

Even if you don’t recognize the lattice pattern, you will be rewarded well if you glimpse this beautiful little orbweaver. She is one of the most widespread species in Ohio, but because she doesn’t usually expose herself in the open, she isn’t as familiar as some others.

female lattice orbweaver (Araneus thaddeus) illustration by Steve Buchanan

female lattice orbweaver (Araneus thaddeus) illustration by Steve Buchanan

Sometimes common names are given to a group of very similar, or related, spiders. For example the grass spiders (the 13 species of Agelenopsis, family Agelenidae).  These spiders are familiar because they build webs at the edge of lawns or near trails.  On dewy mornings, condensation makes the webs conspicuous.  The web has an obvious funnel-shaped retreat where the spider is lurking.

photo of grass spider web

web of a grass spider (Agelenopsis) with its funnel-shaped retreat

It is tough to identify which species of grass spider lives in the web, but at least this name gives you a useful handle for your observations.  In this case, the occupant was the most common of the five species of grass spiders found in Ohio, Agelenopsis pennsylvanica. Here is a photo of this species.

an adult female grass spider Agelenopsis pennsylvanica on her web

an adult female grass spider Agelenopsis pennsylvanica on her web

As of this post, there are 80 common names for spiders in Ohio, roughly 12 percent of the 653 species known for our state.


Sources:

Kaston, B.J. 1978. How to Know the Spiders. WCB McGraw-Hill, Boston, 272 pp.