Australia’s arachnid diversity is truly a beautiful thing, with new spiders still being discovered. This elegant creature is among the latest, unveiled at the inaugural World Science Festival in Brisbane, Queensland on March 9, named in honour of festival co-founder and famous physicist Brian Greene.
Dolomedes briangreenei is a member of the water-spider genus Dolomedes, and was named after Brain Greene because it uses miniscule vibrations on the surface of the water, or waves, to find its prey.
“With the announcement last month of humankind’s first detection of gravitational waves — ripples on the surface of space and time — I am particularly honored to be so closely associated with a spider that has its own deep affinity for waves,” Greene said in a speech at the festival.
Like others of its kind, Dolomedes briangreenei has a fine coat of velvety hairs, in dark brown with white stripes on its head for the male and beige stripes for the female.
These hairs are hydrophobic, which allows the spiders to skate across the surface of water. They can also dive underneath the surface and swim along the bottom. Air trapped in the spider’s hairs forms a sort of fine air coat around the spider; their abdominal lungs then breathe this air, literally allowing the spider to breathe underwater.
The larger members of the genus feast on large food, such as fish and frogs and tadpoles. D. briangreenei is one such spider. To hunt, it attaches itself to the shore with its back legs and spreads its remaining legs across the water. From this position, it can detect find vibrations that alert it to the location of its prey, much like a web-building spider detects vibrations in its web.
The spider can not only tell the distance and direction of the prey, it can also detect how large it is, and distinguish between the vibrations caused by an animal or a leaf falling into the water. When they detect their prey, they run quickly across the water and use small claws at the tips of their legs to capture whatever it is. They can then paralyse their prey with venom before returning to the safety of land to eat.
In addition to aquatic prey and insects, D. briangreenei also preys on cane toads, a destructive introduced species that has wreaked havoc on Australian ecosystems and is nigh impossible to manage. This makes D. briangreenei an impressive and useful little beastie indeed.
And don’t worry. Although Australia seems to have a lot of animals that are venomous to humans, the Dolomedes genus is not among them.