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 [1] which is reflected in their large diversity of behavior.
Almost all known spider species are predators, mostly preying on insects and on other spiders, although a few species also take vertebrates such as frogs, lizards, fish, and even birds and bats. [2] [3] [4] Spiders' guts are too narrow to take solids, and they liquidize their food by flooding it with digestive enzymes and grinding it with the bases of their pedipalps, as they do not have true jaws.
Though most known spiders are almost exclusively carnivorous, a few species, primarily of jumping spiders, supplement their diet with plant matter such as sap, nectar, and pollen. [5] [6] [7] However, most of these spiders still need a mostly carnivorous diet to survive, and lab studies have shown that they become unhealthy when fed only plants. [6] One exception is a species of jumping spider called Bagheera kiplingi , which is largely herbivorous, feeding mainly on the sugar rich Beltian bodies produced by acacia plants. [6] [7] [8]
Many spiders, but not all, build webs. Other spiders use a wide variety of methods to capture prey.
Web: There are several recognised types of spider web
The net-casting spider weaves a small net which it attaches to its front legs. It then lurks in wait for potential prey and when such prey arrives, lunges forward to wrap its victim in the net, bite and paralyze it. Hence, this spider expends less energy catching prey than a primitive hunter and also avoids the energy loss of weaving a large orb web.
Bolas: Bolas spiders are unusual orb-weaver spiders that do not spin the webs. Instead, they hunt by using a sticky 'capture blob' of silk on the end of a line, known as a 'bolas'. By swinging the bolas at flying male moths or moth flies nearby, the spider may snag its prey rather like a fisherman snagging a fish on a hook. Because of this, they are also called angling or fishing spider. The prey is lured to the spider by the production of up to three pheromone analogues. [9]
Hunting on land: Jumping spiders, Wolf spiders and many other types of spiders hunt freely. Some of these have enhanced eyesight, sometimes approaching that of a pigeon (although with a much smaller field of vision). They are generally robust and agile. Some are opportunistic hunters pouncing upon prey as they find it or even chasing it over short distances. Some will wait for passing prey in or near the mouth of a burrow.
Hunting on water: Dolomedes spiders hunt by waiting at the edge of a pool or stream. They hold on to the shore with their back legs while the rest of their body lies on the water, with legs stretched out. When they detect the ripples from prey, they run across the surface to subdue it using their foremost legs, which are tipped with small claws; like other spiders they then inject venom with their hollow jaws to kill and digest the prey. They mainly eat insects, but some larger species are able to catch small fish. [10] [11]
Female water spiders (Argyroneta aquatica) build underwater "diving bell" webs which they fill with air and use for digesting prey, molting, mating and raising offspring. They live almost entirely within the bells, darting out to catch prey animals that touch the bell or the threads that anchor it. [12]
Deception: Some spiders hunt other spiders using deception; the jumping spider Portia mimics the movement of captured insect prey on the webs of other spiders. This attracts the owner of the web whereupon Portia pounces and overwhelms the owner. The Australian crab spider (Thomisus spectabilis) manipulates UV signals to attract bees to flowers in which they are hiding.
Trapdoor: Trapdoor spiders construct burrows with a cork-like trapdoor made of soil, vegetation and silk. The trapdoor is difficult to see when it is closed because the plant and soil materials effectively camouflage it. The trapdoor is hinged on one side with silk. The spiders typically wait for prey while holding on to the underside of the door. Prey is captured when insects, other arthropods, or small vertebrates disturb the 'trip' lines the spider lays out around its trapdoor, alerting the spider to a meal within reach. The spider detects the prey by vibrations and, when it comes close enough, leaps out of its burrow to make the capture. Some Conothele species do not build a burrow, but construct a silken tube with trapdoor in bark crevices. [13]
Basket: The Kaira spider uses a pheromone to attract moths and catches the insects with a basket formed from its legs. [14]
Spiders perform cannibalism under a range of circumstances.
Females eating males: Perhaps the most widely known example of cannibalism in spiders is when females cannibalise males before, during or after copulation. For example, the male Australian redback spider (Latrodectus hasselti) is killed by the female after he inserts his second palpus in the female's genital opening; in over 60% of matings, the female then eats the male. However, the theory of the "sacrificial male" may have become greater than the truth. Some believe that this form of cannibalism only occurs in exceptional cases. [15] [16]
Males eating females: Male water spiders (Argyroneta aquatica) show a predilection for mating with larger females, while cannibalizing females smaller than themselves. [17]
Sacrificial mothers: Offspring of the species Stegodyphus lineatus eat their mother. Females of Segestria florentina sometimes die while guarding her eggs and the hatched spiders later eat her.
Non-reproductive cannibalism: Some spiders, such as Pholcus phalangioides , will prey on their own kind when food is scarce. [18]
Death feigning can be used in reproductive behavior of spiders. In the nursery web spider, the male sometimes feigns death to avoid getting eaten by females during mating. [19] Spiders are also well known for their morphological sexual dimorphism. [20]
Spiders exhibit varying levels of sociality. 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. These can form relatively long-lasting aggregations. Some of these aggregations can contain as many as 50,000 individuals as in the case of Anelosimus eximius (in the family Theridiidae). [21] The level of sociality often varies between species (interspecies) but can vary within a species (intraspecies) as well. Many of these social spiders show cooperative brood care, use the same nest (web), and have some amount of generational overlap. [22] A few species, such as Anelosimus eximius , exhibit reproductive division of labor. Some biologists argue that this classifies these species as fully eusocial as these non-reproductives can be considered a non-sterile worker caste. This reproductive division of labor is a result of resource availability and monopolization of those resources. [23]
Although all arthropods use muscles attached to the inside of the exoskeleton to flex their limbs, spiders and a few other groups still use hydraulic pressure to extend them. Spiders can generate pressures up to eight times their resting level to extend their legs, [24] and jumping spiders can jump up to 50 times their own length by suddenly increasing the blood pressure in the third or fourth pair of legs. [25] Unlike smaller jumping spiders, though larger spiders use hydraulics to straighten their legs, they depend on their flexor muscles to generate the propulsive force for their jumps. [26]
Ballooning is a term used for the mechanical kiting spiders use to disperse through the air. A spider or spiderling after hatching will climb as high as it can. The spider then stands on raised legs with its abdomen pointed upwards. After that, it starts releasing several silk threads from its abdomen into the air, which automatically form a triangular shaped parachute. The spider can then let itself be carried away by updrafts of winds, where even the slightest of breeze will suffice. [27] [28] [29]
Spiders have been used in studies which indicate that invertebrates may experience pain. Under natural conditions, orb-weaving spiders (Argiope spp.) undergo autotomy (self-amputation) if they are stung in a leg by wasps or bees. Under experimental conditions, when spiders were injected in the leg with bee or wasp venom, they shed this appendage. But if they are injected with only saline, they rarely autotomize the leg, indicating it is not the physical insult or the ingress of fluid per se that causes autotomy. Spiders injected with venom components which cause injected humans to report pain (serotonin, histamine, phospholipase A2 and melittin) autotomize the leg, but if the injections contain venom components which do not cause pain to humans, autotomy does not occur. [30]
The diving bell spider or water spider is the only species of spider known to live almost entirely under water. It is the only member of the genus Argyroneta. When out of the water, the spider ranges in colour from mid to dark brown, although the hairs on the abdomen give it a dark grey, velvet-like appearance. It is native to freshwater habitats in Europe and Asia.
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.
The raft spider, scientific name Dolomedes fimbriatus, is a large semi-aquatic spider of the family Pisauridae found throughout north-western and central Europe. It is one of only two species of the genus Dolomedes found in Europe, the other being the slightly larger Dolomedesplantarius which is endangered in the UK.
Trichonephila clavipes, commonly known as the golden silk orb-weaver, golden silk spider, golden orb weaver 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.
Argiope keyserlingi is a species of orb-web spider found on the east coast of Australia, from Victoria to northern Queensland. It is very similar in appearance to a closely related north Queensland species, Argiope aetherea. A. keyserlingi is commonly found in large populations in suburban parks and gardens, particularly among the leaves of Lomandra longifolia. Like many species of orb-web spiders, A. keyserlingi shows considerable sexual dimorphism, with the females being many times larger than the males. Mature females can be seen during the summer, and seeing multiple males on the web of one female is not uncommon.
Latrodectus hesperus, the western black widow spider or western widow, is a venomous spider species found in western regions of North America. The female's body is 14–16 mm in length and is black, often with an hourglass-shaped red mark on the lower abdomen. This "hourglass" mark can be yellow, and on rare occasions, white. The male of the species is around half this length and generally a tan color with lighter striping on the abdomen. The population was previously described as a subspecies of Latrodectus mactans and it is closely related to the northern species Latrodectus variolus. The species, as with others of the genus, build irregular or "messy" webs: unlike the spiral webs or the tunnel-shaped webs of other spiders, the strands of a Latrodectus web have no apparent organization.
Misumena vatia is a species of crab spider with a holarctic distribution. In North America, it is called the goldenrod crab spider or flower (crab) spider, as it is commonly found hunting in goldenrod sprays and milkweed plants. They are called crab spiders because of their unique ability to walk sideways as well as forwards and backwards. Both males and females of this species progress through several molts before reaching their adult sizes, though females must molt more to reach their larger size. Females can grow up to 10 mm (0.39 in) while males are quite small, reaching 5 mm (0.20 in) at most. Misumena vatia are usually yellow or white or a pattern of these two colors. They may also present with pale green or pink instead of yellow, again, in a pattern with white. They have the ability to change between these colors based on their surroundings through the molting process. They have a complex visual system, with eight eyes, that they rely on for prey capture and for their color-changing abilities. Sometimes, if Misumena vatia consumes colored prey, the spider itself will take on that color.
Spider cannibalism is the act of a spider consuming all or part of another individual of the same species as food. It is most commonly seen as an example of female sexual cannibalism where a female spider kills and eats a male before, during, or after copulation. Cases of non-sexual cannibalism or male cannibalism of females both occur but are notably rare.
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 10–14 mm, and males 8–9 mm. Their orb webs can have diameters of up to 70 cm.
Sexual cannibalism is when an animal, usually the female, cannibalizes its mate prior to, during, or after copulation. This trait is observed in many arachnid orders, several insect and crustacean clades, gastropods, and some snake species. Several hypotheses to explain this seemingly paradoxical behavior have been proposed, including the adaptive foraging hypothesis, aggressive spillover hypothesis and mistaken identity hypothesis. This behavior is believed to have evolved as a manifestation of sexual conflict, occurring when the reproductive interests of males and females differ. In many species that exhibit sexual cannibalism, the female consumes the male upon detection. Females of cannibalistic species are generally hostile and unwilling to mate; thus many males of these species have developed adaptive behaviors to counteract female aggression.
Spiders are air-breathing arthropods that have eight limbs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude silk. They are the largest order of arachnids and rank seventh in total species diversity among all orders of organisms. Spiders are found worldwide on every continent except Antarctica, and have become established in nearly every land habitat. As of September 2024, 52,309 spider species in 134 families have been recorded by taxonomists. However, there has been debate among scientists about how families should be classified, with over 20 different classifications proposed since 1900.
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.
Pisaurina mira, also known as the American nursery web spider, due to the web it raises young in, is a species of spider in the family Pisauridae. They are often mistaken for wolf spiders (Lycosidae) due to their physical resemblance. P. mira is distinguished by its unique eye arrangement of two rows.
Tigrosa helluo, commonly known as the Wetland Giant Wolf Spider, is a species of spider belonging to the family Lycosidae, also known as wolf spiders. T. helluo was formerly known as Hogna helluo before differences between dorsal color patterns, habitat preferences, body structures, etc. were discovered. The species is native to the United States, Canada, and Mexico. It can be found across the eastern half of the United States, primarily in the Northeast and New England, and as far west as Nebraska and Kansas. T. helluo can be found in diverse habitats including woods, marshes, fields, and riparian areas. Typically, members of this species prefer to live in wetter areas as opposed to dry environments. Males tend to live for around a year and females will live for close to two years.
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.
Agelenopsis pennsylvanica, commonly known as the Pennsylvania funnel-web spider or the Pennsylvania grass spider, is a species of spider in the family Agelenidae. The common name comes from the place that it was described, Pennsylvania, and the funnel shape of its web. Its closest relative is Agelenopsis potteri.
Leucauge mariana is a long-jawed orb weaver spider, native to Central America and South America. Its web building and sexual behavior have been studied extensively. Males perform several kinds of courtship behavior to induce females to copulate and to use their sperm.
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.