Orb-weaver spiders are members of the spider family Araneidae. They are the most common group of builders of spiral wheel-shaped webs often found in gardens, fields, and forests. The English word "orb" can mean "circular", hence the English name of the group. Araneids have eight similar eyes, hairy or spiny legs, and no stridulating organs.
Nephila is a genus of araneomorph spiders noted for the impressive webs they weave. Nephila consists of numerous species found in warmer regions around the world, although some species formerly included in the genus have been moved to Trichonephila. They are commonly called golden silk orb-weavers, golden orb-weavers, giant wood spiders, or banana spiders.
Micrathena gracilis is a spider in the family Araneidae (orb-weavers), commonly known as the spined micrathena or castleback orbweaver. This spider spins a moderately large and very tightly coiled web. The spiders themselves are small and can be found to be anywhere from 4.2 mm to 10.8 mm long. Its venom is harmless to humans. M. gracilis is unique in appearance due to its large spiky abdomen and black and white bodies. Certain spiders of this species can also display a yellow color on the sides of their bodies. These spiders can be seen most active during the end of the summer and beginning of fall. M. gracilis is diurnal and are rarely ever seen active at night.
Trichonephila clavipes, commonly known as the golden silk orb-weaver, golden silk spider, or colloquially banana spider, is an orb-weaving spider species which inhabits forests and wooded areas ranging from the southern US to Argentina. It is indigenous to both continental North and South America. Known for the golden color of their silk, the large size of their females, and their distinctive red-brown and yellow coloring, T. clavipes construct large, asymmetrical circular webs attached to trees and low shrubs in woods to catch small- and medium-size flying prey, mostly insects. They are excellent web-builders, producing and utilizing seven different types of silk, and they subdue their prey by injecting them with venom, as opposed to related species which immobilize their prey by wrapping them in silk first. They are not known to be aggressive towards humans, only biting out of self-defense if touched, and their relatively harmless venom has a low toxicity, posing little health concern to healthy human adults. Due to their prevalence in forests, T. clavipes may be encountered by hikers.
Evarcha culicivora is a species of jumping spider found only around Lake Victoria in Kenya and Uganda. At maturity, E. culicivora spiders have an average size of 5 mm for both males and females. The range in size for either sex is quite small, with females being only slightly larger on average.
Zygiella x-notata, sometimes known as the missing sector orb weaver or the silver-sided sector spider, is a spider species in the family Araneidae. They are solitary spiders, residing in daily-spun orb webs. Z. x-notata is a member of the genus Zygiella, the orb-weaving spiders. The adult female is easily recognized by the characteristic leaf-like mark on her posterior opisthosoma, caudal to the yellow-brown cephalothorax.
Spider behavior refers to the range of behaviors and activities performed by spiders. Spiders are air-breathing arthropods that have eight legs and chelicerae with fangs that inject venom. They are the largest order of arachnids and rank seventh in total species diversity among all other groups of organisms which is reflected in their large diversity of behavior.
Nephila pilipes is a species of golden orb-web spider. It resides all over countries in East and Southeast Asia as well as Oceania. It is commonly found in primary and secondary forests and gardens. Females are large and grow to a body size of 30–50 mm, with males growing to 5–6 mm. It is the second largest of the orb-weaving spiders apart from the recently discovered Nephila komaci. The first, second, and fourth pairs of legs of juvenile females have dense hairy brushes, but these brushes disappear as the spider matures.
Argiope argentata, commonly known as the silver argiope or silver garden spider due to the silvery color of its cephalothorax, is a member of the orb-weaver spider family Araneidae. This species resides in arid and warm environments in North America, Central America, the Caribbean and widely across South America. In the United States, it is found at least in Southern California, Florida, Arizona, and Texas. A. argentata create stabilimenta and a unique zig-zag in its web design, and it utilizes its UV-reflecting silk to attract pollinating species to prey upon. Like other species of Argiope, its venom is not harmful to humans; however, it can be employed to immobilize its prey. A. argentata engages in sexual cannibalism either mid- or post-copulation. One aspect of particular interest regarding this species is its extinction patterns, which notably have minimal correlation with its population size but rather occur sporadically for the species.
Larinioides sclopetarius, commonly called bridge-spider or gray cross-spider, is a relatively large orb-weaver spider with Holarctic distribution. These spiders originated in Europe, have been observed as south as the Mediterranean Coast and as north as Finland, and have been introduced to North America. They are often found on bridges, especially near light and over water. The species tends to live on steel objects and is seldom seen on vegetation. Females reach a body length of 10–14mm, and males 8–9mm. Their orb webs can have diameters of up to 70 cm.
Agelenopsis aperta, also known as the desert grass spider or funnel-web spider, is a species of spider belonging to the family Agelenidae and the genus Agelenopsis. It is found in dry and arid regions across the southern United States and into northwestern Mexico. Their body is about 13–18 mm long and they have relatively long legs in order to run after their prey. Desert grass spiders can withstand very low temperatures even though they do not cold harden. It constructs the characteristic funnel-shaped webs in crevices where the funnel will fit, where they wait in the tube for prey which they can run after using their long legs. They often hunt for their prey at night.
A social spider is a spider species whose individuals form relatively long-lasting aggregations. Whereas most spiders are solitary and even aggressive toward other members of their own species, some hundreds of species in several families show a tendency to live in groups, often referred to as colonies.
Cyrtophora citricola, also known as the tropical tent-web spider, is an orb-weaver spider in the family Araneidae. It is found in Asia, Africa, Australia, Costa Rica, Hispaniola, Colombia, and Southern Europe and in 2000, it was discovered in Florida. C. citricola differs from many of its close relatives due its ability to live in a wide variety of environments. In North America and South America, the spider has caused extensive damage to agricultural operations.
Darwin's bark spider is an orb-weaver spider that produces the largest known orb webs, ranging from 900 to 28,000 square centimetres, with bridge lines spanning up to 25 metres (82 ft). The spider was discovered in Madagascar in the Andasibe-Mantadia National Park in 2009. Its silk is the toughest biological material ever studied. Its tensile strength is 1.6 GPa. The species was named in honour of the naturalist Charles Darwin on November 24, 2009—precisely 150 years after the publication of The Origin of Species.
Holocnemus pluchei, commonly known as the marbled cellar spider, is a species of Pholcidae, a family commonly referred to as "cellar spiders" or "daddy long-legs". This species is distributed across the North Pacific region of the United States, as well as in parts of North Africa, Europe, and the Mediterranean. It is considered a common household spider and builds its nest in attics, basements, and eaves of houses. Although some members of the species live in solitary webs, the majority join already existing webs and migrate to new webs multiple times throughout the course of their lives. A unique feature of H. pluchei is that while in many species of spiders, stridulation commonly occurs by males during sexual encounters, in H. pluchei, females also possess stridulatory organs, and both sexes engage in stridulation.
Stegodyphus sarasinorum, also known as the Indian cooperative spider, is a species of velvet spider of the family Eresidae. It is native to India, Sri Lanka, Nepal, and Myanmar. This spider is a social spider that exhibits communal predation and feeding, where individuals live in large cooperatively built colonies with a nest or retreat constructed of silk woven using leaves, twigs, and food carcasses, and a sheet web for prey capture.
Micrathena mitrata, the white micrathena, is a species of orb weaver in the spider family Araneidae. It is found in a range from the United States to Brazil. The spider has a distinctive appearance with a shiny, black abdomen and spiky, yellowish-brown legs. Its body length ranges from 4 to 9 mm in females and 3 to 4 mm in males. The species is known for its elaborate web, which it uses to capture insects for food. Despite its fearsome appearance, Micrathena mitrata is not considered dangerous to humans and is generally regarded as a harmless spider.
Tetragnatha versicolor is a species of long-jawed orb weaver in the spider family Tetragnathidae. It is found throughout North America, Canada, Central America, and Cuba, but are most common in the United States. T. versicolor is heavily concentrated in New England and the west coast in states like California and Washington. T. versicolor is considered a habitat generalist, and can thrive in many different environments. While they can be found in places like Grasslands, Wetlands, Forests, etc., they prefer dryer areas like normal trees and shrubs. Unlike other spiders in the genus Tetragnatha, T. versicolor will rarely reside near aquatic environments. T. versicolor will typically be colored dark yellow or pale orange and average around 5 mm for males and 6.5 mm for females in length, which is very small for a spider. They are much longer than they are wide, making them very distinct. In addition, T. versicolor can be distinguished from other spiders in Tetragnatha by the distinct separation of the anterior/posterior eyes and the appearance of their reproductive organs. As an orb weaver spider, T. versicolor creates a web to hunt for prey. It will wait at night for prey to stumble into its web and use vibrational signals throughout the web to sense trapped prey. In terms of mating behavior, T. versicolor lacks a distinct courting ritual and will mate with any others in the proximity. Mating behavior is heavily affected by female mating history. In terms of interactions with humans, the bite of T. versicolor is venomous, but not known to cause significant harm.
Metepeira incrassata, also known as the colonial orb-weaving spider, belongs to the spider family Araneidae and genus Metepeira. They are most famous for their social organization and group living behavior. They are generally found in tropical rainforest and agricultural sites in Mexico, and their habitats tend to be highly productive. Their group sizes are relatively larger than other colonial spiders, typically ranging from hundreds to thousands of individuals. 99% of the females are observed to participate in colonial living, generally with at least two other individuals. Because most M. incrassata females are communal, the colonies are often dominated by larger males. There is minimal sexual dimorphism observed in M. incrassata. Unlike other orb-weaver spiders, M. incrassata builds a colonial web by connecting each spider's individual webs together through semi-permanent framelines. These colonial webs of M. incrassata are prone to invasion by kleptoparasitic and araneophagic spiders such as the Theridiidae family. The reproductive cycle of M. incrassata occurs throughout the entire year, with multiple generations sharing the same time period. Within their colonies, M. incrassata is seen to change locations. Larger, fertile females with egg sacs prefer to reside in the central area of the group for increased protection from predators, while the younger spiders are mostly found in peripheral positions. Larger adult M. incrassata are also known to finish web-building earlier than smaller ones, gaining an advantage in strategically positioning themselves.
Pardosa pseudoannulata, a member of a group of species referred to as wolf-spiders, is a non-web-building spider belonging to the family Lycosidae. P. pseudoannulata are wandering spiders that track and ambush prey and display sexual cannibalism. They are commonly encountered in farmlands across China and other East Asian countries. Their venom has properties that helps it function as an effective insecticide, and it is, therefore, a crucial pesticide control agent.
