The Cross Orbweaver is a fascinating spider species that is commonly found in various habitats, including parks, gardens, and near buildings with exterior lighting. These spiders are known for their distinctive appearance, with a pattern on their abdomen resembling a cross or symbol. Originally from Europe, the Cross Orbweaver has made its way to different parts of the world, becoming a familiar sight for many people.
These spiders belong to the orb weaver family, characterized by their unique spiral webs. They are quite active during the day and night, as they continuously build new webs to catch their prey. The Cross Orbweaver’s diet mainly consists of small insects, such as flies and mosquitoes, making them beneficial for controlling pest populations in gardens.
In general, Cross Orbweavers are harmless to humans and prefer to avoid contact. If you come across one of these spiders, it’s best to admire their intricate web and distinctive appearance from a safe distance, without disturbing their natural habitat.
What is a Cross Orbweaver
Identification and Classification
The Cross Orbweaver (Araneus diadematus) is a spider species belonging to the Araneidae family within the animal kingdom (Animalia). Its classification includes:
- Kingdom: Animalia
- Phylum: Arthropoda
- Class: Arachnida
- Order: Araneomorphae
- Family: Araneidae
- Genus: Araneus
- Species: Araneus diadematus
The spider’s physical appearance consists of a yellow-to-brown background color, two wavy longitudinal lines on its abdomen, and several white or yellow spots, forming a cross-like pattern source.
Some distinguishing features of the Cross Orbweaver include:
- Scalloped longitudinal lines (folium) on the abdomen
- Four elongated spots near the anterior end, creating a cross pattern
Other Common Names
This unique spider is also referred to as the European garden spider or Diadem spider due to its origins in Europe. It has since been introduced to many other regions, including North America source.
Appearance and Size
Color Variation and Patterns
Cross Orbweaver spiders, also known as Araneus diadematus, have a distinct appearance. Their abdomen’s background color can vary from yellow to brown, featuring two wavy or scalloped longitudinal lines known as the folium1. These lines often have white or yellow spots within and around them1. Additionally, there are four elongated spots towards the anterior end of the abdomen, creating a cross-like appearance1.
In Cross Orbweaver spiders, there is a noticeable difference between males and females. Both genders exhibit variations in size, with mature females being larger than males2. Here’s a comparison of their general size and appearance:
|Similar to female
|Similar to male
|Broader & rounded
- Females typically have larger, more rounded abdomens, whereas males have narrower abdomens2.
- Males and females share similar color patterns, but usually, females exhibit more vibrant colors2.
It is essential to understand that size and color variations may occur, but the characteristic cross-like pattern on their abdomen can usually help identify them as Cross Orbweaver spiders.
Habitat and Distribution
The Cross Orbweaver Spider (Araneus diadematus) is native to Europe, specifically in northwestern and northern regions. They are commonly found in various habitats such as gardens, fields, and forests.
Cross Orbweaver in North America
Cross Orbweavers have also been introduced to North America, including the United States and Canada. In the US, they are commonly found in states like:
- New England
Here is a comparison table of Cross Orbweaver distribution:
|Examples of Locations
|Northwestern and Northern Europe
|California, Oregon, Washington, New England
In these locations, Cross Orbweavers thrive in different habitats, but they usually prefer areas with abundant vegetation and insects, such as gardens and forests. Their adaptable nature allows them to live in various environments, making them a common sight in North America.
To summarize, the Cross Orbweaver Spider is native to Europe, but has successfully established populations in North America, including the United States and Canada. These spiders are typically found in areas with plenty of vegetation and insects, making gardens, forests, and fields their ideal habitats.
Behavior and Diet
The Cross Orbweaver spider, also known as the Diadem spider, constructs its webs in gardens and other outdoor habitats (Penn State Extension). They are known for creating orb webs, which are:
- Circular in shape
- Compartmentalized with spokes or radii
- Made of sticky silk to capture prey
These spiders generally build their webs during the night and take them down in the morning to avoid attracting unwanted attention from predators.
Prey and Feeding Habits
Cross Orbweavers primarily feed on insects like:
They have a unique way of capturing their prey. Once an insect is trapped in their web, the spider quickly immobilizes it by wrapping it in silk. After that, they inject venom, which paralyzes the prey and starts the digestion process.
Comparing prey size:
Cross Orbweavers are not picky eaters, but their diet mainly consists of small to medium-sized insects found in their habitats. Overall, their foraging habits help in controlling insect populations in gardens.
Reproduction and Life Cycle
Cross orbweaver, also known as the European garden spider or Araneus diadematus, has an interesting mating ritual. The male courts the female by plucking her web, signaling his presence. If she’s receptive, they mate, but the male must be careful, as females may consume them afterward.
Egg Laying and Development
Adult females lay eggs in a cocoon-like structure called an egg sac. Some key characteristics of egg laying and development include:
- Egg sacs are usually created in late summer or early autumn
- A single sac can contain hundreds of eggs
- Spiderlings hatch in autumn or may overwinter until spring
Here’s a brief comparison of Cross Orbweaver’s life cycle phases:
|Female constructs an egg sac
|Contains hundreds of eggs
|Autumn or spring
|Hatch, disperse, and begin to grow
|Mates, lays eggs, and may die in fall
Note: There can be a connection to Halloween due to the presence of spiderlings around autumn, making these spiders symbolic of the season. However, this association is more coincidental than significant.
Interaction with Humans
Bites and Medical Implications
Cross orbweaver spiders belong to the family Araneidae, and although they have the ability to bite, they are not considered dangerous to humans. Some common reactions to their bites include:
These symptoms are usually mild and can be managed with over-the-counter medications. The likelihood of a cross orbweaver spider encounter in daily life is rare due to their preference for shrubs and trees instead of buildings.
Cross Orbweaver’s Role in the Environment
This spider is widely recognized as a beneficial native species, playing a key role in controlling pests in the environment. They are found in various habitats, such as the following:
- Yellowish flowers
- Sphere-shaped structures
Here’s a comparison table between the European Spider of the Year and a common House Spider:
|European Spider of the Year
|Bite effect on Humans
|Mild to moderate
Cross orbweaver spiders are easy to identify due to their distinct markings, which include a cross-like pattern on the abdomen. Famous fictional representations of cross orbweaver spiders include characters like Charlotte from “Charlotte’s Web” and Levi from “Levi the Spy.”
Interesting Facts and Trivia
The Cross Orbweaver (Araneus diadematus), also known as the Pumpkin Spider or Crowned Orb Weaver, is a fascinating species of spider belonging to the Araneae order. Here are some interesting facts and trivia about this amazing creature:
- Cross Orbweavers can be commonly found in gardens, fields, and forests in a variety of locations including Wisconsin, Arkansas, Western and Northern Europe1.
- These spiders are known to be harmless to humans, which makes them not only fascinating to observe but also beneficial for controlling insect populations in gardens2.
- Their background color varies from yellow to brown, and they often have a distinct cross-shaped pattern on their abdomen consisting of four elongated spots3.
- Sexual dimorphism is present in Cross Orbweavers, with males being smaller and having more slender abdomens than females4.
- Fall is a time when Cross Orbweavers become more noticeable as their webs get bigger5.
Here’s a table comparing the features of Cross Orbweavers with Marbled Orbweavers:
|Cross Orbweaver (Araneus diadematus)
|Marbled Orbweaver (Araneus marmoreus)
|Gardens, fields, forests
|Gardens, fields, forests
|Harm to humans
|Yellow to brown
|Orange with brown-purple markings
|Cross-shaped, four elongated spots
|Wisconsin, Arkansas, Western-Northern Europe
|North America, Northern and central Europe
Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.
Letter 1 – Another Cross Spider
Southern Ontario Spider ID
Ran into this tough looking guy in my Garage this morning. Been trying to track it down, but have been unable to as of yet. Just a little larger than a dime as you can see by the photo. Any ideas on what kind of spider it is?
Yours is the second photo of a Cross Spider, Araneus diadematus, that we received today.
Letter 2 – Cross Orbweaver
Sits in a web like a spider… but is it?
Location: Princeton, New Jersey
September 20, 2011 8:51 am
We found this wacky bug sitting in a large spider web at our apartment complex… it doesn’t have the body of any spider I’ve ever seen. Is it even a spider? The pic isn’t as great as it could be, but I didn’t want to startle it. The legs were banded pale and brown, which is a bit hard to see in the pic.
Addendum to ”Sits in a web like a spider…”
Location: Princeton, New Jersey
September 20, 2011 9:04 am
We were able to get a better photo of the insect in question.
Thanks for sending a better photo. This is definitely an Orbweaver, and we believe it is a Cross Orbweaver, Araneus diadematus, the species that NASA sent into space in the early 1970s to determine if spiders could spin webs without gravity. Read all about the Cross Orbweaver on BugGuide, and all about space travelers Anita and Arabella on All About Chemistry.
Letter 3 – Cross Orbweaver
Subject: Female Cross Orbweaver?
Location: Northern Central New Jersey
September 11, 2013 8:13 am
I thought you might be interested in my new acquaintance. I call her Orba. I believe (correct me if I’m wrong) that it’s a female Cross Orbweaver spider. I’ve been walking by her for nearly a month now. Her webs are expansive, intricate and three-dimensional. She’ll take them down and seem to disappear only to reappear by the next day or so building an entirely new intricate web. I can’t get my camera real close to her as there are layers of web from whatever angle I can get. I don’t want to muss up her living quarters! She appeared in mid-August and is still doing very well now as I write this. Love your site! (And I love shooting insects with my camera!)
Signature: Jackie in Jersey
We agree that your spider, which matches this image on BugGuide, appears to be a Cross Orbweaver, Araneus diadematus, though we cannot see the pedipalps visible on the BugGuide image, so we can’t say for certain this is a female. The sexes are more equal in size in the Cross Orbweaver than in many other Orbweavers. The Cross Orbweaver is a species that gained fame in 1973 when Anita and Arabella went into space aboard Skylab 3, which is mentioned in About.com. Your photo of the web actually appears to be two distinct orbs, which would mean two individual spiders.
Letter 4 – Cross Orbweaver, we believe
Subject: Dock spider?
Location: Troy, Michigan
December 2, 2014 11:26 am
This spider was found in the shop where I work, keeping warm by the wood stove. S/he is SO large, his abdomen about the size of a quarter, that he created quite a crowd of spectators. I thought s/he looked a lot like the dock spiders I’ve seen while camping up in Canada, especially the striping and rasps on the legs. Is that what we have here and do you know what kind it might be?
This is not a Dock Spider, a common name for a Fishing Spider in the genus Dolomedes, but rather an Orbweaver in the genus Araneus. Our best guess is that this is a Cross Orbweaver, Araneus diadematus. You can compare your individual to this image on BugGuide. Your Orbweaver is a female. Male Orbweavers are considerably smaller.
Letter 5 – Cross Orbweaver from Canada
Subject: Beautiful spider buddy
Location: Barrie, Ontario, Canada
August 31, 2016 12:53 pm
This spider has taken up residence outside of my back door. It is bigger than the picture gives credit. My sons are fascinated by watching it and I would love to be able to give them some scientific information about our new friend! I just wanted to know what species it is and whether male or female? Thanks!
This is one of the harmless Orbweavers in the family Araneidae, and we are pretty confident this is a Cross Orbweaver or European Garden Spider, Araneus diadematus, and according to BugGuide, it was: “Introduced to North America from Western and Northern Europe.” We are also relatively confident this is a female. With the Orbweavers, females are larger than males. We believe your children will love learning about Anita and Arabella, the first spiders in space, and you can read about them on About.Com.
Letter 6 – Cross Spider
It came for Halloween! Seriously it did!
This picture does not do this guy justice! It was bright red and very dark/black legs – just beautiful. He allowed me to take his picture and was gone within an hour. I’ve looked around for him, but to no avail. What the heck is it??? Thanks so much for your help.
She is an Orbweaver in the genus Araneus, most probably the Cross Spider, Araneus diadematus, sometimes called the Garden Spider.
Letter 7 – Cross Spider
is this a garden spider?
Your website is great. This spider has grown all summer with webs starting from one end of our deck to the other, we sat and watched him for a few hours one night making his web. He is grown very very large. I am hoping he or she is a garden spider, cross spider or barn spider are they all the same?
Thank you so much
You have a Cross Spider. Garden Spiders, Cross Spiders and Barn Spiders are all members of the same group known collectively as Orb Weavers.
Letter 8 – Cross Spider
what’s that spider?
believe this to be a golden orb but not sure…found 10.01.04 in Worcester Massachusetts
Not a Golden Orb Weaver, but a relative called the Cross Spider, Araneus diadematus. It is a European import also known as the Garden Spider.
Letter 9 – Cross Spider
Spider by bedroom window
I’ve just discovered this scary spider outside my bedroom window. Is it poisonous or harmful to either me or my cat? I have just moved to Marin county in Northern California, and my back yard is home to a startling number of spider webs. Could you tell me if there are other spiders I should beware of in this area? We have friends who have small children. Thanks so much for your knowledge and information.
Your Orb Weaver is a Garden Spider or Cross Spider, Araneus diadematus. It can be identified by the median row of diamond-shaped silvery spots on the abdomen traversed by a dark line, hence the common name Cross Spider. According to our Audubon Field Guide this species was introduced from Europe and ranges in the East. Despite California’s strict produce importation laws, new species seem to get introduced. Luckily, this is not a harmful species. The spider builds a large orb web and hangs face down waiting for flying and jumping insects. It is found in city and suburban hardens between homes and shrubs. An unusual habit is that the spider eats the remains of its web and spins a new web each night. Your dangerous spiders are Black Widows and Violin Spiders.
Thank you so much for your interesting reply. We will re-locate the spider to some bushes outside of our yard. Although, it has been kind of fun watching it for a few days. It’s amazing how the web can withstand such strong winds.
Letter 10 – Cross Spider
we have a new "pet"…
a rather large spider (about the size of a half dollar) has taken up residence in our entryway and we can’t seem to match it to any pictures posted in the internet. The body is tear drop shaped. The color is a light cream with bands of brown on the legs. The body has brown markings in what almost looks like lizzard scales. The bands run horizontal to the main axis of the body. We live in the San Francisco Bay area (northern California). I’m attaching a picture (although it’s a bit far away.)
Diane & Katie Thomson
Hi Diane and Katie,
This is one of the Orb Weaving Spiders, the Cross Spider, Araneus diadematus. It is originally from Europe. Some interesting history: On July 28, 1973, Anita and Arabella, two common Cross spiders were launched into space on Apollo Skylab 3. They were able to spin webs in space. Anita died about six weeks later in her cage, presumably from dehydration, and Arabella did not survive splashdown.
Letter 11 – Cross Spider
crazy spider in my yard
can you tell me what this spider is. it lives in my back yard in san francisco.
Your spider is a harmless Cross Spider or Garden Spider, Araneus diadematus. It is an European introduction.
Letter 12 – Cross Spider
Mon, Nov 3, 2008 at 12:14 PM
I found this spider in my yard after running into his/her intricately made web that ran across the entry to my front door. What on earth is it? Thanks! Love the site by the way! 🙂
Your spider is a harmless Cross Spider, Araneus diadematus, a species introduced from Europe and found in both the eastern and western U.S. You can find many images and more information on BugGuide. A bit of trivia for you concerns Anita and Arabella, the names of the first two spiders sent into space. In 1973, Anita and Arabella, female Cross Spiders, were sent into space aboard Skylab 3 as an experiment to observe how gravity affected web spinning. Both Anita and Arabella died of dehydration during the mission, but their bodies are preserved at the Smithsonian Institution for posterity. You man visit About.com to read more about Spiders in Space.
Letter 13 – Cross Spider
Location: Milwaukee, WI
October 18, 2010 9:46 am
This guy lives in my garage. Hasn’t moved in 4 days and is my first time seeing it so, I know it’s not dead or anything. Any idea what kind of spider this is? Looking online, it may be an Orb Weaver but the markings on the back don’t match. Need to know if this is dangerous please. Thanks much!
At first, we supplied you with a short responses acknowledging that this was a harmless Orbweaver, but as we pondered which letters to use for longer responses and postings, we selected your image and letter despite the blurriness of the image because there is something puzzling about your image and because the back story on the species is so interesting. We believe your spider is a Cross Spider, Araneus diadematus, a species that was introduced to North America from Europe and that is now well established in the northeastern quadrant of North America as well as the Pacific coast states. The interesting thing about your image is that the spider is not up-side-down in the web, which is the typical position. The fascinating back story has to do with the most famous Cross Spiders, Anita and Arabella, who were shot into space aboard Skylab 3 as part of a NASA outreach program that answered student questions. Anita and Arabella did weave webs in space, though the web weaving process was altered by weightlessness. Sadly, both Anita and Arabella died before splashdown, but their bodies are in the Smithsonian Institution. Daniel really wanted to see them on his last visit to Washington DC, but time did not permit. You can read more about Anita and Arabella on About.Com and you can read more about Cross Spiders on the University of Michigan Animal Diversity website. Spiders of many types, especially Orbweavers become more visible in the autumn as they mature and continue to spin larger webs. Orbweavers are harmless, though many species are large, colorful and frightening. Perhaps one of our readers will be able to contribute additional information regarding the unusual upright position your individual has taken in the web.
Update from Trevor: Image was inverted
Hi guys, I think the comment that the picture is inverted is correct. Note the deformation in the web at the back legs. When rotated you can see that the spiders weight is pulling on the strands, I have cleaned up the pic and rotated it. It appears then that there is a row of cupboards in the background with objects sitting on the bench top.
Letter 14 – Cross Spider
Subject: Orb Weaver
Location: San Francisco, CA
October 10, 2012 2:09 am
This Orbweaver is residing in my backyard. I suspect it is either a Cross Orbweaver or a Western Spotted Orbweaver, but I was wondering if you could better identify it. I have seen it for the past three days, and today I found it whilst it was wrapping up what appeared to be a honey bee.
Signature: Ben Miller
In our opinion, this is a Cross Spider or Cross Orbweaver, Araneus diadematus, which you can verify on BugGuide. Cross Spiders have the distinction of being the first spiders sent into space when Anita and Arabella were launched aboard Skylab 3 in 1973.
I really appreciate your site. Thank you for all the great info and pictures.
Letter 15 – Cross Spider: Brun Spindel Naerbild
Please help identify
Hi What’s That Bug !
This summer this spider span its net right outside my window. I took some closeup photos. It is about 1 centimeter big. I live in Sweden. It would be interesting to know the name of the spider.
We are very excited to get your photo for many reasons. First this is a Cross Spider or Garden Spider, Araneus diadematus. This spider was introduced to America from Europe and is now common here. It is nice to get a view of its European cousin. Also, two Cross Spiders, Anita and Arabella, were the first spiders shot into space on July 28, 1973. Both Anita and Arabella spun webs in space, but sadly, neither survived the re-entry. We are also curious if in Sweden you commemorate the death of Carl Alexander Clerck on July 22. He is a famous arachnologist who published the book Swedish Spiders. He died in 1765. These are the kinds of facts you will find in our 2006 What’s That Bug? 13 month calendar.
Letter 16 – Cross Spider from Croatia
Location: Zagreb (city center), Croatia, Europe
November 19, 2010 9:50 am
I have this thing living under my outdoor window sill for the past week or so. It’s scary as hell. I’ve never seen this species around here before. It made this yellow ball that can be seen under it. The photo was taken today. The outside temperature goes to near 0°C at night at this time, and it seems to be pretty comfortable with that. Please tell me what it is. Thanks!
This is a female Cross Spider with her egg sac. She is a harmless Orbweaver and her species, Araneus diadematus, has the distinction of being the first spiders sent into space when Anita and Arabella we sent into orbit in 1973 aboard Skylab 3 to see how spiders would spin webs in weightlessness. You may read about Skylab 3 on the About Chemistry website. Your spider will probably not survive very much longer, but her eggs will hatch in the spring.
That was super fast!
Letter 17 – Cross Spider from Ireland
Location: Dublin, Ireland
October 3, 2011 8:26 am
This spider is in my garden, but I’ve never seen one like it before. What is it?
Your spider is one of the Orbweavers, and we are nearly certain it is a Cross Spider, Araneus diadematus. Two Cross Spiders named Anita and Arabella were the first spiders sent into space aboard Skylab II as an experiment to see if Spiders could spin webs in space. They were chosen in part because the orb web of the Cross Spider is very regular. This European species has been introduced to North America where it has naturalized. You may read more about the Cross Spider on BugGuide.
Letter 18 – Cross Spider from UK
Location: Birmingham, England
October 23, 2010 7:06 am
I like in Birmingham, UK, and spotted a strange spider today – it was about 3cm across, hairy and the markings on its back were a very bright gold. I took a picture as I’ve never seen a spider like it before, and was wondering what it is and if it’s actually native to Britain.
Signature: Sarah Clark
The Cross Spider or Garden Spider, Araneus diadematus, is a European species that is common in the UK and information regarding it may be found on the UK Safari website. The species has the distinction of providing the first spiders, Anita and Arabella, to be shot into space aboard Skylab II. Here is some information from the Aerospace Guide website:
“Although the STS-107 spiders were the first Australian animals in space, they weren’t the first spiders in space. Anita and Arabella, two female cross spiders (Araneus diadematus) went into orbit in 1973 for Skylab 3 space station. Like the STS-107 experiment, the Skylab experiment was a student project. Judy Miles, from Lexington, Massachusetts, wanted to know if spiders could spin webs in near-weightlessness. Here is Judith Miles:
In zero gravity, a lot of things tumble, roll, flip and tip. Can you name something that spins in zero-gravity? Hint: it has eight legs and would scare Miss Muffet.
That’s right: a spider. In this case, two of them. Anita and Arabella took off into space way back in 1973. They were on board Skylab, an early, experimental orbiting space station. Also on board were 720 fruit flies, six mice, two minnows and 50 minnow eggs! Busy place.
What was this creature-zoo up to? They were all part of student experiments. Anita and Arabella were onboard for high school student Judy Miles from Lexington, Massachusetts. Judy wondered if spiders could spin webs in weightlessness. Good question.
So, the lucky student got to team up with NASA space scientists to design an experiment that would measure how well spiders weave their webs in space.
So what did Judy and NASA learn? Zero gravity didn’t stop Anita and Arabella from doing what spiders do — spin webs.
This little bit of first spider in space
Spiders have been astronauts in space missions. In 1973, the two common cross spiders “aranous diadematus” Arabella and Anita became famous for their stay in the Skylab space station.
Both spiders were successful in spinning webs in weightlessness; examples can be seen in above images.
Unfortunately, these two spiders did not return safely: Anita died in-flight before returning, and Arabella was found dead after splash-down of the Skylab-3 (2nd manned mission) Apollo CM.
Arabella and Anita have the right stuff. These two common spiders were NASA’s first eight-legged astronauts! Anita and Arabella got their mission because a high-school student named Judy Miles wondered if spiders could spin webs in a weightless environment. She suggested sending spiders into space to find out. NASA space scientists liked her proposal and went to work designing special cages, lights, and cameras.
On August 5, 1973, Arabella and Anita blasted off into space on Skylab II. On her first day in orbit, Arabella didn’t do well. She spun sloppy webs and obviously felt the effects of weightlessness. However, by her third day in space, she was spinning just as though she were back at home. Her webs were finer in space, which was expected. But the pattern remained the same. She proved that spiders can spin nearly Earth-like webs in space.
Though Arabella and Anita have both died, their bodies remain at the Smithsonian, memorialized for their small, vital part in increasing our knowledge of space.“
Letter 19 – Cross Spider or Garden Spider
what am I?
Now that I have looked through your site and feel completely crawly, can you ID this awesome spider? My son found it and 2 others in our yard and has taken to tossing worms into the webs to feed them. This by the way is really cool to watch. Anyways, is it one I should be weary of? Thanks in advance.
Your Cross Spider is also known as a Garden Spider, Araneus diadematus. It is a harmless European import.
Letter 20 – NOT an Hermaphrodite Orbweaver: Gray Cross Spider
Subject: Hermaphroditic Orb Weaver?
Location: Towanda, Bradford County, PA
August 26, 2012 10:26 am
These photos are of orb weaver spiders I saw in Bradford County in NE Pennsylvania in late July and August 2012. They appear to be female, in all respects except that they have large bulbs on the ends of their pedipalps. Needless to say, I was very excited when I found these little creatures, and very curious to find out more about them.
In a small area, there were a few of these hermaphrodites, as well as many ”true” males and females that appeared to be of the same species. I took several photos of the males and females for comparison with the hermaphroditic ones, and would be happy to send those photos to you. The hermaphroditic spiders seem to have slightly smaller abdomens than the females, but their abdomens are larger than those of the males. Their legs seem to be the length of the females’ legs. Also, their behavior seems more female than male – hanging still in their webs with their legs held relatively close to their bodies.
I have since found a few references online of people reporting that they have found hermaphroditic spiders (including a photo of a wolf spider that appears to be male on one side of its body and female on the other). Any help you can give would be greatly appreciated. Thank you.
Signature: Sarah from Philadelphia, PA
We are very impressed with your thought provoking submission to our site, which is why we are going to devote more than the average amount of time to posting it and we are also going to feature it. Additionally, we are strapped for time this morning as our staff needs to get to work for the first day of fall semester, so this will be our only posting this morning. The boundary between the sexes is often blurred in the natural world. We suspect this might be a genetic trait that can be inherited, which could explain the unusual population of Orbweavers in your vicinity. First, we cannot say for certain which species of Orbweaver this is, and we also are reluctant to commit to a genus. Araneus seems possible, as does Neoscona. We do not feel qualified to provide a scientific response to your submission, however, we are more than comfortable speculating on a few matters.
We would love one additional photo of a female and one of a male to add to this posting in the future. Please choose representative images for us. We would also like if you could supply us with the links you discovered during your research. The bilateral Wolf Spider hermaphrodite you describe is a phenomenon occasionally seen in insects, and the most dramatic example we have on our website is an Eastern Tiger Swallowtail with the female half also exhibiting the less common dark coloration found in a small percentage of female Tiger Swallowtails. This bilateral hermaphrodite is called a gynandromorp. We suspect your spiders are more likely true males or females that exhibit some physical characteristics of the other sex, like the Transvestite Rove Beetle in our archive. Perhaps there is some advantage to mimicking the other sex. When time allows, we will try to contact a few folks with better credentials that might be able to shed some light on this unusual mystery.
Eric Eaton provides an excellent explanation.
I strongly suspect that the “hermaphrodites” are simply penultimate (one molt away from adulthood) males. I just learned recently that after the last molt, adult male orb weavers not only lose interest in spinning webs, they actually lose the ability to do so. They have only one mission as adults: find females to mate with. Because they are not capturing prey (at best they are catching far fewer insects), and are roaming long distances looking for mates, adult male web-spinning spiders become quickly emaciated, with shrunken abdomens. Their legs then look proportionately longer (their legs *are* longer to begin with, but the effect is magnified by the shrinking abdomen).
The images do not show anything unusual in this species, which is the Gray Cross Spider, Larinioides sclopetarius, family Araneidae.
Update from Sarah
31 August 2012
Thanks so much for posting (and featuring!) my photos and question. Thanks also for the fascinating and enlightening information Daniel and Eric provided in response. I was surprised that the male spiders would not have undergone their final molt by the date on which I took the photos (Aug. 23), that their abdomens shrink after that final molt, and that they spin webs like females before adulthood. Do their legs actually grow longer upon their final molt?
You asked me for photos of the female and adult male that were in the same location as (what I now know are) the penultimate males. I have attached them to this message. These photos were taken the first couple days of August, when I first saw this particular group of spiders.
You also asked for the resources I found about hermaphroditic spiders. Here is a link to a posting and photos of a gynandromorph wolf spider I found on arachnoboards.com: http://www.arachnoboards.com/ab/showthread.php?208102-Wolf-Spider-Hermaphrodite&s=af18ea376db83e3af777983d26de5395
The same photos were posted on bugguide.net. That posting includes links to a couple articles on gynandromorphic spiders. Here’s the link to the bugguide.net page: http://bugguide.net/node/view/512530
Lastly, your website is wonderful! It never fails to interest and amaze me.
Thanks for the update and links Sarah. Contributions like your submission make our website possible.
Letter 21 – Oval St. Andrew’s Cross Spider from Sri Lanka
Subject: Identify a spider
Location: Gonagaldeniya, sri lanka.
August 30, 2015 8:33 am
Dear bugman, i want to identify this spider. He lived under the roof of our house. We are in the wet zone. And sri lanka is a tropical counrty. He builds a strong and sticky web..
Signature: Tharindu Dilshan
Your spider is an Orbweaver, and we believe it is in the genus Argiope. Large Orbweavers are capable of biting people, but they are docile spiders that rarely leave their webs, and the bite is not considered dangerous. Thanks to images posted to WongChunXing.com, we believe you have an Oval St. Andrew’s Cross Spider, Argiope aemula. According to A Guide to Common Singapore Spiders on Habitat News: “Unlike many other Argiope spiders, the abdomen is oval. Argiope spiders make webs which are suspended vertically 1-2 metres from the ground, the web of mature female spiders of this genus can be easily recognised by the X-shaped zigzag bands of white silk in the centre of the web.”
Letter 22 – Possibly Male Cross Spider
I have visited your interesting site, but I need your help. Yesterday I have made a macro of a spider and I would like to know its scientific & common name… We are in France / Europe. In advance thank you very much for your help.
With the Orb Web Builders, the female spider is often several times larger than the male and it is the female, with her longer lifespan, that attracts most of the attention, including photographic documentation in books and on websites. I believe, though I am not sure, that your spider is a male Orb Web Builder in the genus Araneus, possibly the Cross Spider, Araneus diadematus. This spider is native to Europe, but has been introduced to the U.S. We just got two photos of females yesterday.
Ed. Note: Check out Christian’s website.
Letter 23 – St. Andrew’s Cross Spider from Australia
Location: Sydney Australia
January 19, 2016 1:56 am
Is that a Nursery Web spider?
Interesting web addition in the direction of the legs.
This St. Andrew’s Cross Spider, Argiope keyserlingi, is an Orbweaver, not a Nursery Web Spider. According to the Australian Museum: “The role of the cross-like web decoration, called the stabilimentum, has long been a puzzle. At first thought to strengthen or ‘stabilise’ the web, more recent ideas associate it with capturing prey or avoiding predators. The ribbon-like silk reflects ultra-violet light strongly. Such light is attractive to flying insects, which use it to locate food sources like flowers and to navigate through openings in the vegetation. If the stabilimentum silk attracts insects it may increase the web’s prey catching efficiency. The silk decoration could also make the web and its owner more obvious to day-active predators like birds and wasps. However, the variability of the shape of the cross decoration (a complete cross; a partial cross with from one to three arms; or sometimes absent altogether) could make web recognition confusing for the predator. Another possibility is that the stabilimentum advertises a warning to predators like birds to stay away – after diving through the sticky web, the effort required to clean silk off plumage may deter birds from trying again.”
Letter 24 – St. Andrew's Cross Spider from Australia
St. Andrew’s Cross Spider from Australia
February 21, 2010
Hi again, I thought of checking out how many posts you’ve got on St. Andrew’s Cross Spiders, and was surprised to see only one (from Singapore). They are very common at our place, so I thought of taking some fresh photos of them for your site, but came across another spider that I haven’t seen before here, and took photos of it. So, I’m sending you a couple of older images that I’ve taken of the St. Andrews. Hope you can use them.
Thanks for the excellent images. We believe we had additional images of St. Andrew’s Cross Spiders, Argiope keyserlingi, and they might have gotten lost when we did a website migration last year. We may check our old computer for the posts. The Brisbane Insect website has nice images and helpful information on this species.
Letter 25 – St. Andrew's Cross Spider from Australia
Location: NSW, Australia, near the coast.
December 10, 2011 12:17 am
Hi, I noticed you only have a couple of posts about St Andrew’s cross spiders. I thought you might like this picture of one that’s living on a plant outside our house.
Thanks for sending your excellent images of a St. Andrew’s Cross Spider, Argiope keyserlingi, to flesh our our archives. The Australian Museum has a nice page on the species. The name St. Andrew’s Cross Spider refers to the X-shaped stabilimentum woven into the web by the spider. It is commonly believed that St. Andrew was crucified by the Romans on an X-shaped cross in the first century AD.
Wow, That’s morbidly interesting! I’m glad you liked the photos. Thank you!
Letter 26 – St. Andrew's Cross Spider from Singapore
spider in web with stabillamenta
Tue, Feb 3, 2009 at 5:51 PM
i found this spider in a forest.i think its a saint andrews cross spider.Can you help me identify it?
The St. Andrew’s Cross Spider, Argiope versicolor, is found in Singapore according to Joseph K H Koh’s Guide to Common Singapore Spiders, and the web in your image is perfectly consistent with that of the species, so we are confident your identification is correct. Our memories of our own Catholic education did not provide a reason for the X stabilimentum and the life and death of St. Andrew, and we are quite curious since we are currently working on a book chapter on Entomology and Etymology, and your letter gives us a wonderful excuse to try to do a bit of research. We located the following on Wikipedia: “Andrew is said to have been martyred by crucifixion at Patras (Patrae) in Achaea . Though early texts, such as the Acts of Andrew known to Gregory of Tours ,describe Andrew bound, not nailed, to a Latin cross of the kind on which Christ was crucified, a tradition grew up that Andrew had been crucified on a cross of the form called Crux decussata (X-shaped cross) and commonly known as ” Saint Andrew’s Cross “; this was performed at his own request, as he deemed himself unworthy to be crucified on the same type of cross on which Christ was crucified. ”The familiar iconography of his martyrdom, showing the apostle bound to an X-shaped cross, does not seem to have been standardized before the later Middle Ages,” Judith Calvert concluded after re-examining the materials studied by Louis Réau. ”