Sex life of funnel-webs caught on camera

By AG STAFF 19 May 2023
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The complex mating rituals of the Sydney funnel-web spider have now been described in detail for the first time, with sexual routines including leg and body vibrations and female lifting filling a missing link in the study of spiders.

The fascinating courtship and mating behaviours of the highly venomous Sydney funnel-web spider (Atrax robustus) have been caught on camera.

In a study by experts, including Flinders University ecologist Dr Bruno Buzatto, and staff at the Australian Reptile Park, the ground-dwelling spiders were found to practice “safe sex”.

“While the high level of toxicity and development of anti-venom has seen the funnel-web studied in the past, little is actually known about its ecology,” says Bruno.

“This is the first reconstruction of mating behaviours in funnel-web spiders – their behavioural repertoire is difficult to document due to the concealed life in funnel-shaped webs that are built in soil and leaf-litter habitats.”

Flinders University ecologist Dr Bruno Buzatto Image credit: Courtesy Flinders University.

Videos have been collected inside and outside funnel-web burrows, and shed light on the male’s elaborate pre-copulatory display in front of a female’s burrow, as well as leg, body and lunging displays, and lifting the female before final copulation.

“Female Sydney funnel-web spiders appear to remain quiescent during mating but some copulations ended with the male being chased away by the female,” says Bruno, adding cannibalism in these spiders is rare and probably more likely in captivity rather than in the wild.

The study also provides fresh insights into the use of the male funnel-web spider’s ‘clasping spurs’ located on its second pair of legs.

Related: World’s deadliest spider: the funnel-web

“It has been assumed that the Sydney funnel-web has these mating or clasping spurs to keep the female upright while they mate – so the female cannot attack, kill or eat the male.

“However, our study suggests the spurs are used to pull the female towards the male and keep them there – and probably have more a sexually selective function than one to avoid cannibalism.”

The spiders used in the study were part of the breeding and venom collecting program run at the Australian Reptile Park in Somersby, on the NSW Central Coast. Different mating pairs were filmed in 451 videos and 165 minutes of footage, with the average 20mm adult males and 27.5mm females commonly venturing from their own funnel-web burrows for mating.

“There is a gap in our knowledge about sexual behaviour in male and female funnel-webs and other mygalomorphs (including tarantulas and trapdoor spiders) so we hope this paper inspires future studies in this gap in information.”

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