Geographic Range 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. (Culter, et al., 2006; Hardy, 2003; Hoffman, 2010) Biogeographic Regions

nearctic native



Development 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. (Culter, et al., 2006; Foelix, 2011) Development - Life Cycle

metamorphosis

Lifespan/Longevity 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. ("Spiders", 2012; Culter, et al., 2006; Foelix, 2011) Range lifespan

Status: wild >7 (high) years

Behavior Spiders of the family Atypidae are more commonly called “purse-web” spiders due to their unique ability to capture prey using the wall of a silk-tube. These distinctive webs are an effective way to find red-legged purse web spiders. These spiders form vertical tubes by attaching one end to a tree, rock, or concrete wall and the other end into soil several centimeters away. Females spend their entire lives in burrows at the bases of their tubular webs, while adult males do not build webs, wandering long distances in search of potential mates. Webs are widest below and at the surface of the soil, and become thinner and fragile toward the top anchor point. Females can extend their webs a foot or more up the trunk of a tree. The outer side of the web may be covered with soil and debris, camouflaging it. Because this species is rare, little is known about their social behavior. On Tuckernuck Island, Massachusetts, dense populations have been found where this species occurs in groups ranging from small aggregations to large colonies. This may be due to low predation rates on this island. (Coyle and Shear, 1981; McKenna-Foster, et al., 2011) Key Behaviors

arboreal

terricolous

diurnal

motile

sedentary

solitary Home Range Female home ranges are typically limited to their webs while males wander over wide areas (up to 200 meters). (Herberstien and Wignall, 2011)

Food Habits 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. (Coyle and Shear, 1981) Primary Diet

carnivore insectivore eats non-insect arthropods

Animal Foods

insects

terrestrial non-insect arthropods Foraging Behavior

stores or caches food

Predation 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. ("Red-legged purse web spider-Arachnids Reference Library", 2012; Culter, et al., 2006; Foelix, 2011) Anti-predator Adaptations

aposematic Known Predators Fire ant (Solenopsis)



Ecosystem Roles 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. (Coyle and Shear, 1981; Newton, 2008)

Economic Importance for Humans: Positive 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. (Coyle and Shear, 1981; Newton, 2008) Positive Impacts

controls pest population

Economic Importance for Humans: Negative No negative effects are known. (Newton, 2008)

Contributors Audrey Urquhart (author), University of Michigan-Ann Arbor, Jeremy Wright (editor), University of Michigan-Ann Arbor.

Glossary Nearctic living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico. aposematic having coloration that serves a protective function for the animal, usually used to refer to animals with colors that warn predators of their toxicity. For example: animals with bright red or yellow coloration are often toxic or distasteful. arboreal Referring to an animal that lives in trees; tree-climbing. bilateral symmetry having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria. carnivore an animal that mainly eats meat chemical uses smells or other chemicals to communicate delayed fertilization a substantial delay (longer than the minimum time required for sperm to travel to the egg) takes place between copulation and fertilization, used to describe female sperm storage. diurnal active during the day, 2. lasting for one day. ectothermic animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature female parental care parental care is carried out by females fertilization union of egg and spermatozoan forest forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality. heterothermic having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature. insectivore An animal that eats mainly insects or spiders. internal fertilization fertilization takes place within the female's body iteroparous offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes). metamorphosis A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis. motile having the capacity to move from one place to another. native range the area in which the animal is naturally found, the region in which it is endemic. oviparous reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body. pheromones chemicals released into air or water that are detected by and responded to by other animals of the same species polygynous having more than one female as a mate at one time seasonal breeding breeding is confined to a particular season sedentary remains in the same area sexual reproduction that includes combining the genetic contribution of two individuals, a male and a female solitary lives alone sperm-storing mature spermatozoa are stored by females following copulation. Male sperm storage also occurs, as sperm are retained in the male epididymes (in mammals) for a period that can, in some cases, extend over several weeks or more, but here we use the term to refer only to sperm storage by females. stores or caches food places a food item in a special place to be eaten later. Also called "hoarding" suburban living in residential areas on the outskirts of large cities or towns. tactile uses touch to communicate temperate that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle). terrestrial Living on the ground. tropical savanna and grassland A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia. savanna A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome. temperate grassland A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands. urban living in cities and large towns, landscapes dominated by human structures and activity. venomous an animal which has an organ capable of injecting a poisonous substance into a wound (for example, scorpions, jellyfish, and rattlesnakes). vibrations movements of a hard surface that are produced by animals as signals to others visual uses sight to communicate