The Pet Tree House - Where Pets Are Family Too : Peacock Spiders: Noted for Their Spectacular Courtship Display, Are Extremely Tiny – 4 to 6mm in Length

Wednesday, April 8, 2015

Peacock Spiders: Noted for Their Spectacular Courtship Display, Are Extremely Tiny – 4 to 6mm in Length

Members of the genus, commonly referred to as peacock spiders, belong to the jumping spider family Salticidae.

These spiders are extremely tiny – 4 to 6 mm in length, and are most noted for their spectacular courtship display.

The magnificent color on the males’ abdomens is from iridescent scales (which reflect light in both the visible and/or UV range), much like those found on moths and butterflies. By contrast, females are cryptically colored.

The genus contains around 30 recognized species, all of which – except Maratus furvus from China – are endemic to Australia.

The two new species, scientifically named Maratus jactatus and Maratus sceletus, were found in the Wondul Range National Park, southern Queensland, Australia.

Maratus jactatus, nicknamed Sparklemuffin, is a tiny spider: males are barely 4.5 mm long, though females are a bit bigger, up to 5.3 mm long.

The species name jactatus means ‘rocking (jolting)’ in Latin, a reference to the very rapid lateral rocking that punctuates the courtship display of males of this species.

“Male Maratus jactatus display by tilting the expanded fan to one side or the other, and then moving the extended ipsilateral leg III, mostly behind the fan,” the scientists wrote in a paper published in the journal Peckhamia.

“At cycles of 1-3Hz, the extended leg that is positioned behind the fan is first lowered over 0.2-0.4 s, then rapidly raised (or returned to its position behind the fan) to trigger a very rapid jolting or rocking movement of the whole body that lasts for only 20-30 msec. This rocking involves rapid ipsilateral (in the direction of the extended leg and tilted fan) rotation, followed by a return to the original position.”

Nicknamed Skeletorus, Maratus sceletus resembles other members of the genus in their general pattern, but has little colouration and is mostly black and white.

“The species group name (sceletus, noun, Latin) means skeleton, a reference to the bold, skeleton-like appearance of the male spider,” Dr Otto and Dr Hill wrote in the paper.

Males are 3.7 to 4.2 mm in body length, while females are 5.0 to 5.3 mm.

“Male Maratus sceletus generally approach the female from the opposite sideof a stem or blade of grass. If the female is on top, the male approaches from below, in a hanging position,” the scientists wrote.

“If the female is positioned belly-up beneath a stem, the male approaches from above. The fan dance of the male rapidly alternates from one side of a stem to the opposite side. Positions may be switched 10 times in a 20 s interval, with only 1 s or less of display in a single position.”

“The fan is prominently elevated and often waggled from side to side during this display, but the greatest and most rapid movement is that of the extended spinnerets, separately twitched from side to side. During display, the pedipalps are often moved up and down in front of the clypeus and chelicerae. One leg III is elevated but also flexed, displaying a prominent black stripe with little significant movement.”


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