Shelob's Great Grandaughter in the Russian Sage

Almost three years ago to the day, Laurie took pictures of a Banded Garden Spider (Argiope trifasciata) in the herb garden.

Yesterday, not ten feet away, in the overflow of the Russian Sage from the Perennial Demonstration Garden to inside the fence of the vegetable growing area, another specimen caught my eye, which I have dubbed Shelob's Great Grandaughter.

I think she's just beautiful.  From a reasonable distance, that is.

Pictures by Jenn Wetzel. 

Here’s another blog post from 2010 on one of her cousins Argiope aurantia (Yellow Garden spider).


Lots more information with embedded links at the links referenced above.

Hole-ly Orb Weaver Spider

Although the image I get seeing those horns, conjures up denizens not of a holy place ... 

Quinn Cashell, one of our 4-H Summer assistants (who also noticed the imperial moth last month) brought in these pictures of a very weird looking spider, found while boating in Huntingdon County.

Micanthra sagitatta

Before I got a chance to ID it (I was sorting through crab and spiny orb weaver pictures), Quinn came up with the right identification, googling - yellow, black and red horned spider - yielding Arrow Shaped Micanthra Spider, or Micanthra sagitatta.

Micanthra sagitatta

I encouraged her to take some entomology classes when she returns to college in a few weeks.

The "Hole-ly" used in the title is a reference to the hole in the center of the web they weave which, according to Wikipedia, is made to assist in motion.  Here's a video of the spider grooming and keeping house.




Like the other orb weaving spiders we've highlighted on the blog in the past, they belong to the Family Araneidae.

The name Micrathena comes from Greek meaning "Little Athena" (Micro - Athena) and sagittata means "shaped like an arrow" in latin.  According to Greek legend, the goddess Athena and the mortal Arachne engaged in a weaving contest wherein Arachne arrogantly mocked the gods.  Athena touched her forehead, making her feel so ashamed of her impudence, she hanged herself.  Taking pity, Athena revived and then transformed Arachne:

She sprinkled her with the juices of aconite, and immediately her hair came off, and her nose and ears likewise. Her form shrank up, and her head grew smaller yet; her fingers cleaved to her side and served for legs. All the rest of her is body, out of which she spins her thread, often hanging suspended by it, in the same attitude as when Athena touched her and transformed her into a spider.

The class of inverterbrates that spiders belong to, along with mites, harvestmen (Daddy Long Legs), ticks, and scorpions is called the Arachnida after Arachne. I also like the horticulture connection with aconite - the beautiful, but poisonous Monkshood, or Wolfsbane - Aconitum napellus.

Spiders in the Mist

Spider Web

My partner caught this picture of a dew-y spider web as the fog lifted Wednesday morning, 9/21/11.  The web's shape indicates its spinner is one of the approximately 2500 species of spiders in the family Araneidae who create the characteristic circular web seen here.  From the Ohio State University Fact Sheet:

Orb weaver spiders construct the familiar circular, flat, elaborate web in which flying insects are trapped. Each species of orb weaver typically constructs a web with a distinctive design. Webs usually occur outdoors. These spiders have poor vision and locate their prey by feeling the vibration and tension of the threads in their web. They use silk to wrap the victim.

Many species of orb weaver spiders are large (approximately 1 inch), but others are quite small (approximately 0.1 inch). Some have oddly shaped abdomens (pointed spurs, conical tubercles, etc.). Some are very brightly colored. One common spider, known as the yellow garden spider (Argiope aurantia), has silver hairs on the back of the cephalothorax and a large abdomen marked in black and bright yellow or orange. This spider is about 1 inch long and hangs head down in the center of the web, which is found in brambles, bushes, tall grasses, etc. in open sunny places.

Despite their formidable appearance, orb weaver spiders are not considered dangerous. Some species can bite if handled.

The University of Illinois adds, "The orb weaver produces an oil in its mouth and spreads this oil on the body, preventing it from sticking to its own web. They paralyze their prey with venom and then crush it with their pedipalps (a set of mouthparts.) Once the prey is crushed, the liquids in its body are consumed. Spiders mate by males spinning small webs that they place sperm in, and then transfer the webs to the female."

Previous encounters with these beneficial arthropods can be found here and here.

Shelob's Cousin in the Peppers

Last year Laurie and Alex captured beautiful pictures of a Banded Garden Spider, Argiope trifasciata, hanging around the herb garden. This year, Autumn Philips, Steve's summer assistant, alerted us to one of that spider's cousins, a Yellow Garden Spider, or Argiope aurantia, protecting the peppers in the high tunnel.

These are some of the largest and showiest of the spiders commonly encountered in Pennsylvania. They are seen in gardens, tall weeds, and sunny areas with bushes and other supporting structures on which they build their large orb webs. Yellow garden spiders are found throughout most of the United States.

As Laurie noted in her email to me:

 "...if you look at the photo of the spider's underside, the head area looks like batman's face."

And so it does.

More pictures from Laurie's husband, Keith, and Alex follow.

Here are fact sheets on Pennsylvania Spiders from the PSU Entomology page.



Photo by Alex Surcica



Shelob in the Lavender

I reached down to collect some calendula seeds in the Herb Demonstration Garden on Monday, and came up close and personal with this beautiful spider.

Laurie C. was kind enough (and brave enough – given her confessed arachnophobia) to come in and get pictures.

The web is right in the middle of the lavender patch at the center of the Herb Garden.

We’ve narrowed the ID down to Argiope aurantia (Yellow Garden Spider), or Argiope trifasciata (Banded Garden Spider) and asked Alex to confirm.

Argiopes, like other orb-web spiders, weave an additional pattern of white silk in their webs (visible in the center of the web in the first picture), called stabilimenta. Scientists are unsure of the purpose of the stabilimenta, speculating that they provide an additional attractant for prey, that they can be used to scare off predators, or that they provide a visible means for birds and mammals to notice the web and leave it undisturbed. One of the common names for aurantia, is writing spider, for the resemblance of the stabilimenta to writing. Charlotte must have belonged to this family.

The Cooperative Extension Fact Sheet, Commonly Encountered Pennsylvania Spiders, is an excellent resource to hand out to the public when you're covering the help desk and you're asked about a spider specimen.

Check out this battle between an aurentia garden spider and a huge cicada-killer wasp.

UPDATE: Alex says A. trifasciata and sends this picture of A. aurantia that he took in Delaware County, PA.


















UPDATE II: Alex went back to the Herb Garden and took these pictures: