An arachnophobe’s nightmare has been discovered in the tropical forests of South Africa and Madagascar: Nephila kowaci, the world’s largest web-spinning spider. 400–500 new species are added to the 41,000 known species of spiders each year, but the webs of the Nephila kowaci will put hairs up on backs of necks of many, save the most passionate arachnologists.
Females of this newly discovered species have bodies that are 3-4 centimeters (1.5 inches) long and legs that are 7.5cm long (3 inches) while males are, surprisingly, to the uneducated only a a fifth of the female’s size.
The new species of orb spider is the largest member of an already big family. 15 species of Nephila – golden orb weavers are known to exist, with bodies that are more than an inch long. Many spin webs in excess of a meter in diameter.
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Discovery of Nephila Kowaci
Scientist, Linnaeus first identified the first of the large web spinning species in 1767, and 140 years ago, in 1879 the most recent find was described. Thousands of specimens have been collected and are on exhibit at natural history museums across the world. However, every attempt to discover a new Nephila species since 1879 (there are over 150 suggested scientific names on file) has resulted in nothing more than cobwebs, as the so called new species, were found to be only specimens of existing spiders.
All of that changed in 1978, when a new Nephila spider was discovered in South Africa’s Sodwana Bay. The Smithsonian Institution’s Matjaz Kuntner and Jonathan Coddington were intrigued by the unusual spider. Several expeditions were launched to observe the elusive orb spider, but all of them failed.
They were beginning to suspect that they had discovered a hybrid or a species that had become extinct since its brief encounter with discovery but they blew out the cobwebs of their sleuth suitcases and persevered.
In 2003, their efforts spun success when they discovered a second specimen from Madagascar sitting, inconspicuously in an Austrian museum. This orb spider was not a crossbreed as was first feared. Exciting news followed two years later from South Africa’s Tembe Elephant Park., when three more were found … a female and a male.
N.komaci was confirmed as a new golden orb-weaver species, the first to be described in nearly a century, and was worth the wait. Andrej Komac, Kuntner’s close friend, unfortunately, died when these findings were being made, so in remembrance, the arachnologists named the incredible Nephila after him.
Nephila are renowned for being the largest web-spinning spiders, making the largest orb webs, and are model organisms for the study of extreme sexual size dimorphism (SSD) and sexual biology.
Arachnologist, Matjaž Kuntner
Physical Characteristic of Nephila Kowaci
Females of N. komaci are the largest Nephilas discovered to date, displaying extreme sexual dimorphism that is common in Nephilas species of spiders. The size of a male reaches a leg span of only about 2.5 centimeters, with a body length of about 9 mm, which is roughly one fifth of that of a female; a female’s tip-to-tip leg span is approximately 12 cm (body length approximately 4-5 cm).
Kuntner and Coddington used measurements from this new species to reconstruct the evolutionary history of this family of eight-legged giants. By constructing a family tree of golden orb-weavers and related spider families, the duo demonstrated that females grew in size as the group diverged and evolved. N.komaci is the epitome of that evolutionary enlargement, being seven times larger than the group’s ancestor.
Evolution, Distribution and Conservation
In terms of size, the enormous females all cluster around one branch of the family tree, but the males show no similar patterns. Species with huge males are not more closely related than species with small males. These patterns strongly show that the large size variations between male and female Nephila are due to the females’ growth rather than the males’ shrinkage.
From a reproductive standpoint, the females’ bodies inflated over time, which makes reasonable because the larger the body size, the more eggs she can lay.
This family can teach us a lot about the evolution of size differences between sexes, which is a common occurrence in the animal kingdom. Nonetheless, its discovery is accompanied by a familiar warning. It’s possible that the species is already in jeopardy.
It’s difficult to say if the species is facing extinction, with only five individuals ever seen, but the spider has only been found in two areas – parts of Maputaland-Pondoland-Albany, South Africa and Madagascar – that are hotspots of endangered wildlife.
Mating – Not For The Faint of Heart
Those of a squeamish disposition should skip this part. When the female has molted (spiders shed their hard-exterior exoskeleton in order to grow), the male will inseminate her and break of his genitalia within hers, plugging the space, preventing other males from mating with her. The sterile male will spend the rest of his life fighting off the advances of other males wishing to mate with her.
Q & A About Nephila Kowaci
Are Nephila spiders poisonous?
Nephila spiders will not bite you unless you poke and threaten them. Their bites may sting and cause redness, but their venom is harmless to healthy humans.
How Large are the Largest Spider Webs in The World?
Webs of Nephila kowaci, are thought to be the largest in size, with great webs of golden silk, measuring more than a meter (3 feet) in diameter.
What type of silk does Nephila Kowaci Use for its Webs?
The Nephila Kowaci uses stronger ‘scaffolding’ silk for structure and softer sticky interconnecting threads to trap prey.
How Strong is the web of Nephila Kowaci?
The webs of Nephila Kowaci are spun with a tensile strength stronger than Kevlar.
What genus is the Nephila Kowaci?
The Nephila Kowaci is from the genus Nephila.
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