Golden silk orb-weaver, Golden silk spider, Banana spider
Trichonephila clavipes (formerly known as Nephila clavipes), commonly known as the golden silk orb-weaver, golden silk spider, or colloquially banana spider (a name shared with several others), 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.
Like many orb-weaver species, T. clavipes shows sexual dimorphism, with females possessing both a larger size and more complex and noticeable coloration. Males of the species do not suffer sexual cannibalism or genital mutilation to the same rate that males of other related species in the subfamily Nephilinae do, making T. clavipes a focus of study into the mating behaviors of spiders. The species shows both monogynous and polygynous mating, with a preference for polygyny in most mating environments.
T. clavipes is a well-studied species with a high recognized value to humans because of their usefulness in spider silk research. Analysis of the species' genome, the first of the orb-weaving spiders to be completely annotated, has revealed 28 unique genes for the proteins comprising spider silk, known as spidroins. Furthermore, the silk of T. clavipes has the potential to aid in surgeries involving the nervous system, a capability which has been demonstrated in past experimental studies.
The specific epithet clavipes is derived from the Latin: clava, which can mean "club" or "knotted staff"; and pes, meaning "of or pertaining to a foot". As a whole, the name means "club-footed." Linnaeus, who named the species in 1767, was likely referring to the noticeable tufts of hair on the females' legs, giving them a clubbed or knotted appearance.
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TerrestrialTerrestrial animals are animals that live predominantly or entirely on land (e.g., cats, ants, snails), as compared with aquatic animals, which liv...
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OviparousOviparous animals are female animals that lay their eggs, with little or no other embryonic development within the mother. This is the reproductive...
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Not a migrantAnimals that do not make seasonal movements and stay in their native home ranges all year round are called not migrants or residents.
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starts withLike most orb-weavers, the species displays marked sexual dimorphism in both size and color pattern. T. clavipes females are some of the largest non-tarantula spiders in North America, ranging from 24 mm to 40 mm in length when fully developed. It is possible that they are even the largest orb-weaver species indigenous to the United States. Females also have very distinct coloring, making the species relatively easy to recognize. They have a silvery white cephalothorax and a longer orange-brown abdomen with two rows of small white-yellow spots. The abdomen changes color as the spider matures. Their legs consist of dark yellow and brown banding, and the first, second, and fourth leg pairs also contain black brush-like tufts of hair near the joints.
Males, meanwhile, are much smaller, about one-third to one-quarter the size of females at roughly 6 mm in length, and also have a more slender build. Their mass is roughly between 1/30th and 1/70th that of a large female. Male coloration, meanwhile, is much less complex, consisting of a dark brown body and legs. Males' legs contain a black band near the end of the tibial segment, in the same area as where the black hair tufts would be on a female.
T. clavipes resemble its congener Trichonephila plumipes in that the females both possess a collection of stiff hair on their legs. However, the hairs of T. plumipes are more closely set together than those of T. clavipes.
T. clavipes feed on small flying insects. Webs constructed by this species are used to catch this prey. They can feed on grasshoppers, flies, and other small insects. As the prey is entangled in the strong web, T. clavipes wrap it in silk like a casing.
In T. clavipes, males move from web to web, attempting to mate with the female web-owners. Males risk death with each move to a new web, largely due to predation, and this mortality risk increases as the breeding season progresses, so that the risk is lower in the early stages of the season and highest in its later stages. As a result, males are more choosy in the early season than they are in the late season.
