Description of Araneus diadematus
The range of the Araneus diadematus extends from New England and adjacent Canada across the northern states to Washington, Oregon, and British Columbia.
Biogeographic Regions: nearctic (Native )
- Kaston, B. 1972. How To Know the Spiders. Dubuque, Iowa: Wm. C. Brown Company Publishers.
Regularity: Regularly occurring
Type of Residency: Year-round
Female Araneus diadematus have lengths of 6.5 to 20 mm, whereas males are 5.5 to 13 mm. Color ranges from pale yellow brown to nearly black. The folium is not as distinct as some other Araneus species and includes a number of white or yellow spots. The largest spots are arranged longitudinally near the anterior end. Usually there is a pair of white spots at right angles to the longitudinal ones, which gives the group the form of a cross. The cross arrangement is more apparent in darker individuals and is caused by guanine cells which shine through the transparent cuticle. The carapace has a median and marginal dark bands. There are four pairs of legs which fan out radially from the connecting carapace and sternum. Each leg has seven segments: a coxa and a trochanter, which are both short; a long femur and a kneelike patella; a slender tibia and metatarsus; and finally a tarsus with three claws. The first pair of legs are relatively long and used as feelers for probing the environment. Sensory hairs densely cover the distal leg segments. The external sex organs of males and females are observed ventrally. Both male and female genital openings lie inside the epigastric furrow, except that the epigynum is situated in front of the female furrow. Males also have a bulb or palp used for the storage of sperm.
Range length: 6.5 to 20 mm.
Other Physical Features: ectothermic ; heterothermic
Sexual Dimorphism: sexes shaped differently
- Foelix, R. 1982. Biology of Spiders. Cambridge, Massachusetts: Harvard University Press.
Araneus diadematus lives in grasslands and requires some form of moisture. The environment must provide plenty of attachment sites for the scaffolding of the web and there must be sufficient vertical open space for the orb web.
Habitat Regions: temperate ; terrestrial
Terrestrial Biomes: savanna or grassland
- Wise, D. 1993. Spiders in Ecological Webs. New York: Cambridge University Press.
The ultimate purpose of spider webs is to capture prey and orb webs are well-suited for this. They are highly geometrical, with the hub slightly higher than the center so that the spider may run down the web quickly. The area nearer the hub is coated more densely with sticky globules. Araneus diadematus individuals spend most of their time on the web's hub monitoring vibrations in the silk with their sensitive legs. Females rest on one side of the web and monitors by holding onto a signal thread. When catching prey, Araneus diadematus individuals wrap prey in silk thread before consuming it. After killing and wrapping their prey, these spiders may not immediately consume the prey. The number of prey attacked and killed may decrease as the number of prey increases and the spiders become satiated. Spiders eat primarily arthropod prey.
Animal Foods: insects; terrestrial non-insect arthropods
Primary Diet: carnivore (Insectivore )
Life History and Behavior
Communication and Perception
Araneus diadematus individuals integrate information from the central nervous system and visual system. A spider will orient its body axis perpendicular to the path of a moving object in order to view the object with the main eyes. Input from the secondary eyes causes the spider to turn without any visual feedback. However, when a moving object is viewed only by the secondary eyes, a spider will not always turn towards it.
Perception Channels: visual ; tactile
The internal reproductive organs of Araneus diadematus resemble those of other arthropods. Females have paired ovaries that lie in the abdomen and join to form a common oviduct which ends in the uterus and opens to the outside in the epigastric furrow. Females also have a pair of spermathacae or seminal receptacles where sperm taken in during copulation is stored until egg-laying. In males, a common duct is formed by a pair of coiled testes in the abdomen and opens to the exterior at the centre of the epigastric furrow. Males exude sperm through the epigastric furrow onto a sperm web and transfer it to their palps. The terminal palp is the sperm reservoir and carries out insemination through a narrow tube known as the embolus. The palp serves as a pipette which can suck up and release seminal fluid. Blood pressure within male palps increases so that sclerotized projections such as hooks and spines elevate into position to grasp on to the surface of the epigyne. Only the correct palp will fit into the appropriate epigyne. This ensures successful mating only between individuals of the same species. Males search for a female and are rather cautious when approaching a female, because they risk being considered prey. Males embrace the female's abdomen during copulation and insert one palp. Afterwards, the male leaves and his palps are refilled with sperm. This process may only be repeated a few times since the life expectancy of males is shorter than females.
Mating System: polygynous
Females breed once, dieing shortly after laying their eggs. Individuals of this species breed at the end of the warm season, with young hatching in the following spring.
Key Reproductive Features: semelparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (Internal ); oviparous
Before the female starts making her egg sac, she withdraws for several days. She then spins a thin layer of single, tightly-woven silk threads. The first layer is molded by her abdominal movements into a disk, known as a basal plate. Then she crawls underneath the basal plate and continuously turns around in circles spinning the cylindrical wall. The palps are held in contact with one side of this wall while spinnerets are placed on the opposite wall. After about two hours, the cylindrical wall grows to 5 mm in height. Cocoon size is directly related to the size of the spider, but not necessarily to the number of eggs it will hold. Females wait for a few minutes and begins to lay eggs and cover them in a tight pack of silk threads. This becomes the cover plate and the spider continues to add layers of thread to it. The loop mesh ultimately wraps around the entire surface of the egg sac. Females remain close to the cocoon for the next few days in case the threads need repairing. Females die a few days after the egg sac is built. The cocoon will appear unchanged externally while the spiderlings develop for a few months. The offspring emerge in spring and release fine threads of silk from their spinnerets to be carried off by the wind to new locations. Their journey through the air is called ballooning. Wherever each spider drops from the sky will be where its new life begins.
Parental Investment: no parental involvement; precocial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Protecting: Female)
- Dewey, J. 1993. Spiders Near and Far. New York: Dutton Children's Books.
- Foelix, R. 1982. Biology of Spiders. Cambridge, Massachusetts: Harvard University Press.
- Preston-Mafham, K., R. Preston-Mafham. 1996. The Natural History of Spiders. Ramsbury, Malborough: The Crowood Press Ltd.
Molecular Biology and Genetics
Statistics of barcoding coverage: Araneus diadematus
Public Records: 13
Specimens with Barcodes: 58
Species With Barcodes: 1
Barcode data: Araneus diadematus
There are 12 barcode sequences available from BOLD and GenBank. Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species. See the BOLD taxonomy browser for more complete information about this specimen and other sequences.
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Download FASTA File
There is no special conservation status for this species.
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
National NatureServe Conservation Status
Rounded National Status Rank: NNA - Not Applicable
NatureServe Conservation Status
Rounded Global Status Rank: GNR - Not Yet Ranked
Relevance to Humans and Ecosystems
Economic Importance for Humans: Positive
Araneus diadematus individuals feed on insects, helping to reduce the population of insect pests. People can use clean spider's web on a cut or wound to stop bleeding.
Positive Impacts: controls pest population
- Parsons, A. 1990. Amazing Spiders. New York: Alfred A. Knopf, Inc..
European garden spider
European garden spider (orb-weaver) varieties are very commonly found throughout Europe and North America. In America, their range extends from New England and the Southeast to California and the Northwestern United States. They can also be found in parts of southern Canada adjacent to the United States.
Size and markings
Individual spiders' colouring can range from extremely light yellow to very dark grey, but all European garden spiders have mottled markings across the back, with five or more large, white dots forming a cross. The white dots result from cells filled with guanine, which is a byproduct of protein metabolism.
Adult females range in length from 6.5 to 20 mm (0.26 to 0.79 in), while males range from 5.5 to 13 mm (0.22 to 0.51 in). During mating, the much smaller male will approach the female cautiously. If not careful, he could end up being eaten by her (see video below).[dead link]
The third pair of legs of garden spiders are specialized for assisting in the spinning of orb webs. These spiders also use them to move around on their web without getting stuck. These legs are very useful only in the web; while on the ground, these legs are of little value. Since this tends to be a passive animal, it is difficult to provoke to bite—but if it does, the bite is just slightly unpleasant and completely harmless to humans.
The webs are built by the larger females who usually lie head down on the web, or in a nearby leaf (with a signal thread attached to a leg), waiting for prey to get entangled in the web. The prey is then quickly captured and wrapped in silk before being eaten. Like many other orb weavers, the spider will use its legs to violently oscillate its web if it feels threatened, in an attempt to ward off potential predators. Orb spiders are said to eat their webs each night along with many of the small insects stuck to it. They have been observed doing this within a few minutes. A new web is then spun in the morning.
References and notes
|Wikispecies has information related to: Araneus diadematus|
|Wikimedia Commons has media related to Araneus diadematus.|
- Nikita J. Kluge (2007). "Case 3371. Araneidae Clerck, 1758, Araneus Clerck, 1758 and Tegenaria Latreille, 1804 (Arachnida, Araneae): proposed conservation" (PDF). Bulletin of Zoological Nomenclature 64 (1): 15–18.
- Cross Orbweaver; at BugGuide online; retrieved April 2013
- Cross Spider, Washington NatureMapping Project
- Rainer F. Foelix (1992). Biologie der Spinnen [Biology of the Spiders] (in German). Stuttgart: Thieme. ISBN 3-13-575802-8.
- Cross Orbweaver, Penn State Entomology
- "European Garden Spider". Archived from the original on 2012-07-29., Down Gardens Services[dead link]