Spiders in the Cairns Botanic Gardens

Buggin with Bridgey is a Monthly report of sightings from the Let’s Go Buggin Cairns Nature Tour in the Cairns Botanic Gardens.  As the months roll by, subtle changes in the seasons bring sightings of new creatures and this report aims to give people a wrap up of the current animals seen as well as provide an ongoing citizen science account of our wonderful critters that can be seen in the tropical north of Queensland.

Buggin with Bridgey – July 2022

Mirrorball Spider (Thwaitesia sp.)

Mirrorball Spider (Thwaitesia sp.)

Arguably one of the most striking spiders the world has ever seen are the Mirrorball spiders.   Perfectly evolved to disappear in their rainforest habitat. Their mirror-ball like abdomen reflects light as though it’s a drop of rainwater. Their tiny bodies with long legs are extremely challenging to find let alone photograph.  Luckily for participants on Let’s Go Buggin Night Walks, they can be seen all year round in the Cairns Botanic Gardens.

Their silver-lined abdomens is the result of a digestion bi-product, known as ‘guanine’ that lines the inside of the abdomen instead of being excreted.   Surely, this is the fanciest looking ‘poo’ that planet earth as created!

Mirrorball Spiders (Thwaitesia sp.), the last image is a Mirrorball Spider with Green Tree Ant victim.

Net-Casting Spiders (Deinopidae)

I first became aware of Net-Casting Spiders watching a David Attenborough documentary about life in the undergrowth. I was captivated by the idea that an arachnid could create its own fishing-net out of silk.

The ’net’ of a Net-casting Spider truly is magnificent and has a subtle light-blue tinge.  Watching them spin this web is also quite mesmerising.  She gathers the silk with her legs at a frantic pace and with elegant precision attaches each section in perfect lengths until she has a rectangle formation.   The final step of the fishing-net weaving process is a stretch-test.  She positions the corners of the net in opposing toes and with one striking move, stretches the net to 4 times its size and then lets it settle back to its resting position ready to strike.

Then, while patiently waiting in ambush, with what seems like laser-focused meditation until unsuspecting prey walks beneath them…they launch their fishing-net with their tippy-toes and surround the animal with her highly elasticised silk.  Once snared, a victim is unlikely to escape.

Net-Casting Spider (Deinopidae)

Huntsman Spiders (Sparassidae)

Like all Australians, I had unsettling experiences with huntsman spiders in my house as a child. Their ability to scurry along ceilings and walls at incredible speeds was enough to make you run squealing from the room. However, since doing photography night walks and getting my lens sometimes only millimetres away from the faces of Huntsmans sitting on leaves or tree trunks, I’ve come to see them differently.  They will keep perfectly still, allowing myself and other photographers to get extreme closeups and even multiple images to focus-stack.  I have a newfound affection for these wonderful animals.

The majority of the Huntsman Spiders we see are during Let’s Go Buggin Night Walks in the Cairns Botanic Gardens are Jungle Huntsmans (Heteropoda jugulans).  They remind me a lot of cats with their furry bodies with dapples down their legs.  The species, that seems to impress most of the tour participants are Fire-back Huntsman (Beregama cordata) due to their lovely orange colouration.  Whilst the Giant Grey Huntsman Spider (Holconia immanis) is also as awesome, due to their impressive size.  We also regularly see Badge Huntsmans, which are fast-becoming one of my favorites as well.

Jungle Huntsman (Heteropoda jugulans), Fire-back Huntsman (Beregama cordata), Giant Grey Huntsman Spider (Holconia immanis), Badge Huntsman (Neosparassus salacius)

Golden Orb (Nephila)

Probably the most impressive of the spiders found in the Wet Tropics are the Golden Orbs.  The females can reach the size of your hand, with abdomens as big as a small thumb.  Their webs easily reach a metre and sometimes can be two metres across.  Their namesake comes from the golden silk that can be seen with the naked eye on these massive webs.  The females rule the roost and can have a harem of many males all lining up to be her suiter…or dinner.   There’s been a number of times I have seen some of these massive spiders and have just been totally frozen in awe of their presence.  The most striking individuals (in my opinion) are the ones who have a red colour morph in their legs like the one pictured.

Golden Orb-Weaver Spiders (Nephila) showing red colour morph

Jumping Spiders (Salticidae)

I couldn’t really write an article about spiders in the Cairns Botanic Gardens without mentioning everybody’s favourite spiders, the jumping spiders.  These charismatic little bundles of joy steal the hearts of pretty much all of Let’s Go Buggin tour participants when they see their cute little faces with huge doting eyes.  People are also charmed by their inquisitive nature and super cute body language.

We do have some absolutely stunning species in the Wet Tropics, including these from the Cosmophasis genus.   Their rainbow-coloured metallic hairs glistening in the sun is one of nature’s little slices of heaven on earth.  Regularly seen all year-round are Cosmophasis bitaeniata, micarioides and thalassina.   Of the later two species, it is the female who stands out as the prettiest with a huge variation of colours, whilst the males sport only black and a silvery blue colour combination.

Cosmophasis species C. micarioides, C. bitaeniata, C. thalassina

Join me to explore the Cairns Botanic Gardens to try and spot some of these beautiful spiders on a Let’s Go Buggin Night Walk.  Use ‘blog’ as the coupon code for 20% discount on your tour booking.

Next Blog end of August 2022.