Female red-legged purseweb spiders sense prey through vibrations generated on the web and it is hypothesized that males sense female webs through pheromones. In general, spiders communicate during courtship using mechanical, chemical, and visual signals. Hairs present on their legs help spiders to sense their surroundings.
Communication Channels: visual ; tactile ; chemical
Other Communication Modes: pheromones ; vibrations
Perception Channels: visual ; tactile ; vibrations ; chemical
Red-legged purseweb spiders, although scarcely found in nature, are not listed on any conservation lists.
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
Species-specific developmental research is quite scarce for red-legged purse web spiders. In general, the development of a spider consists of three phases: the embryonic, larval, and nympho-imaginal periods. In the embryonic period, an egg is fertilized and the body is formed. During the larval stage, some morphological characteristics are undeveloped and the spiders are unable to feed on their own. In the nympho-imaginal period, organs fully develop. The nymph (juvenile) looks like a miniature adult but it is not sexually mature. This system is known as incomplete, or simple metamorphosis. A juvenile spider grows into an adult through molting, where the exoskeleton is sloughed off between growth phases. Juvenile spiders remain at the site of their first web until reaching maturity, a period of several years. Male red-legged purseweb spiders usually exhibit a change in behavior after their final molt as they begin to search for mates. A closely related species, Sphodros abotti, has been observed laying eggs in August, which hatched in late September. The mean number of juvenile spiders hatched per web found for this species was found to be 79.7.
Development - Life Cycle: metamorphosis
No negative effects are known.
The clearest benefit for humans may be the management of ground level arthropods. These spiders are rarely encountered by humans and are not pests. While venomous, they only serve as a threat to those who are highly sensitive to insect bites.
Positive Impacts: controls pest population
Red-legged purseweb spiders are known predators of a variety of terrestrial arthropods. In addition, they are prey to birds, small mammals, and other spiders. Beyond this, relatively little is known about how this species impacts the ecosystem. In general, nematodes (roundworms) are known to be parasites of spiders that cause reduction in size of muscles, midgut, and reproductive system. Most spiders die just before or after the parasite exits the body.
Red-legged purse-web spiders are predators. Many mygalomorph spiders consume quite large prey, sometimes up to twice their own size, due to the span of their chelicerae. This species typically feeds on a variety of ground surface arthropods including crickets, beetles, wasps, worker ants and caterpillars. Male red-legged purseweb exoskeletons have been found in tube-webs, suggesting that females may consume their mates. This species spins tube webs which, unlike webs designed to trap prey, are non-sticky. Females depend on their speed and alertness to get to a place where an insect is crossing their webs. When prey reach the web, females protrude their oversized chelicerae through the silk and into the prey, then folding their fangs back immediately. Using silk, females pull prey into the tube and immediately repair the hole made from the prey by applying silk from the spinnerets.
Animal Foods: insects; terrestrial non-insect arthropods
Foraging Behavior: stores or caches food
Primary Diet: carnivore (Insectivore , Eats non-insect arthropods)
Red-legged purseweb spiders have the largest geographic distribution of all species in the family Atypidae (atypical tarantula), from the southeastern United Sates as far north as Rhode Island and Massachusetts and as far west as Kansas.
Biogeographic Regions: nearctic (Native )
Red-legged purseweb spiders prefer to attach their webs to small hardwood trees. They also form webs on grassy vegetation and non-wooded structures. They primarily live in temperate forests but may also occupy metropolitan areas. Studying this species in the wild can be challenging as they prefer undisturbed woody habitats with good leaf and soil cover, and tend to be solitary and shy.
Habitat Regions: temperate ; terrestrial
Terrestrial Biomes: savanna or grassland ; forest
Other Habitat Features: urban ; suburban
Research on the lifespan of this species is limited. Mygalomorph spiders tend to be long-lived, compared to their sister taxa, Araneomorphae. Females can live to seven years or more. The lifespan for males is unknown.
Range lifespan
Status: wild: >7 (high) years.
All Sphodros have a similar physical appearance, characterized by a stocky, robust body held low to the ground with short, strong legs. In Red-legged purseweb spiders, the body is divided into two segments: the cephalothorax, which is black in color, and the abdomen (also called the prosoma or opisthosoma). As Arachnids, they have 12 appendages total which are connected to the cephalothorax: one pair of chelicerae, one pair of pedipalps, and four pairs of legs. The posterior of the cephalothroax is flattened while the anterior slopes upward. The dorsal plate of the cephalothorax is known as the carapace, and the ventral side known as the sternum. Chelicerae, consisting of two parts (a basal segment and a movable fang) are attached to the front of the carapace. In this species, the chelicerae are oversized (1/2 length of carapace) and are used for capturing prey, defense, and for grasping items. Two pairs of venom glands are located in the cephalothorax, connected to the fangs (used to bite and envenommate prey). Red-legged purseweb spiders have eight black eyes grouped close together on the front end of the carapace and three pairs of abdominal spinnerets used to construct tube-webs. Activities related to reproduction often lead to increases in metabolic rate, with females investing more energy into production of the eggs and males investing more energy in respiration.
Males are easily distinguishable from females by their crimson red legs. It has been hypothesized that this coloration may be a mimetic or aposematic display, advantageous to wandering males. The carapace is reddish brown to black with several small yellowish spots with chelicerae that often reach the length of the cephalothorax, are almost three times as long as they are wide, broad at the base, and with rough, curved hairs and spines. The abdomen is dull black, oval shaped, and covered with many black hairs. Males can reach up to 14.5 mm in length.
Females can reach up to 25 mm in length, making this the largest Sphodros species. Their chelicerae are about twice as long as they are wide and broadest at the base, similar to the males. The carapace is reddish-brown and their legs are the same color as the carapace, with a dull black to dark brown abdomen.
Range length: 14.5 to 25 mm.
Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry ; venomous
Sexual Dimorphism: female larger; sexes colored or patterned differently; male more colorful; sexes shaped differently
Remains of male red-legged purseweb spiders have been found in tube webs, suggesting that males may fall prey to their mates. These spiders are sometimes eaten by birds, small mammals, and other spiders. Male coloration (deep red legs) may be a form of aposematism, perhaps an advantage for wandering long distances in search of mates. The continued spread of fire ants, a probable predator of this species, may affect populations of red-legged purse web spiders.
Known Predators:
Anti-predator Adaptations: aposematic
Little is known about the specific reproductive behaviors of American Sphodros species. However, it is well documented that after their final molt, spiders develop pedipalps, an additional pair of appendages. In males, pedipalps are used for storing and transferring sperm while in females the pedipalps are simply shortened legs (not used for locomotion). Males of the related species S. abboti have been observed discovering female tube webs. Tubes of adult female S. abboti webs are hypothesized to be marked with sex pheromones, suggesting that the prime cause of courtship and mating in Sphodros is due to a contact chemical produced by adult females.
Mating System: polygynous
Research on the specific reproductive behavior of Sphodros is very limited. It has been noted that the bottom of the purse web is enlarged; it is in this area that egg sacs are laid and guarded by females. In general, it is well known that spiders are always dioecious, sperm-storing and oviparous. Research has suggested that male red-legged purseweb spiders are diurnal and search for mates in June and it is known that these spiders take several years to reach sexual maturity.
Breeding interval: Red-legged purse web spiders breed annually.
Breeding season: Red-legged purse web spiders likely mate in the summer.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (Internal ); oviparous ; sperm-storing ; delayed fertilization
Specific data regarding parental investment is limited for this species. However, it is well known that among spiders, females provide a wide range of maternal care, whereas males do not. This is evident in red-legged purse web spiders, as females spend the entirety of their lives in their tube webs while males wander long distances (up to 200 meters) in search of potential mates. In general, female spiders invest more energy than males in the reproduction process as they must produce eggs, while males invest comparatively little energy in the production of sperm.
Parental Investment: female parental care ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Protecting: Female)
Sphodros rufipes, sometimes called the red legged purseweb spider, is a mygalomorph spider from the southern United States, though it has been photographed as far north as Indiana, Missouri, New Jersey, Minnesota, Tennessee, Delaware, Louisiana, and Tuckernuck Island in Massachusetts [West Virginia]. A recent sighting shows that these spiders can also be found in Canada. Recent sighting also in Kansas.[1]
The species name rufipes is Latin for "red foot".
This spider is also sometimes known as Sphodros (Atypus) bicolor, a synonym.
These spiders are solid and strong-looking and their bodies are black. The males have distinctive long red or red-orange legs, and the females have black legs. Females are known to reach a length of about 25 mm, or just under an inch, though they may also get slightly larger. Like other spiders in its infraorder mygalomorph, it has fangs that point straight down rather than crossing.
This spider has a distinctive method of catching its prey. It spins a tunnel of silk against the side of a tree or supported by stones or other convenient objects, and waits for its prey to land or climb on the side of the tunnel. Then the spider bites through the silk walls and pulls the prey inside. These spiders rarely leave their webs for any reason other than mating.
A male Sphodros rufipes, showing its large vertical fangs in a threat display
.jpg)
Sphodros species tube
Sphodros rufipes, sometimes called the red legged purseweb spider, is a mygalomorph spider from the southern United States, though it has been photographed as far north as Indiana, Missouri, New Jersey, Minnesota, Tennessee, Delaware, Louisiana, and Tuckernuck Island in Massachusetts [West Virginia]. A recent sighting shows that these spiders can also be found in Canada. Recent sighting also in Kansas.
The species name rufipes is Latin for "red foot".
This spider is also sometimes known as Sphodros (Atypus) bicolor, a synonym.
