Unusual dry-country encounter

A little while back while searching for trapdoor spiders in the dryer open forest west of Kuranda I discovered an animal that I certainly didn’t expect to – a crab. The crab was living about 400mm underground in a burrow not dissimilar to that of trapdoor and wolf spiders, only that it lacked silk lining.  The burrow was about 30 metres from a dam and was within heavy clay soil. The crab is most likely an Inland Freshwater Crab, Austrothelphusa sp. – crabs that are well adapted for dry conditions. They can cope with extended drought conditions of up to 6 years and can survive sealed in their humid burrows until rains come. During this time they apparently can lose up to 50% of their body water and still survive.

I have recently visited the site again, and the area is now under water. This time I was able to find them in a more conventional way – in the water with a net!

Another Tiger Huntsman!

Another Tiger Huntsman (Typostola sp.) has turned up - only the second wild specimen that we have encountered since finding the first in 2006. The species is still undescribed and the only specimens in captivity (with us at Minibeast Wildlife and some at Melbourne Museum) are descendants from the original female which was gravid at the time of capture.

This specimen turned up in Kuranda inside a possum nesting box. It is an adult female in pristine condition. The couple who found it had not seen such a stunning spider before, so Googled its description and found the articles from the 2006 discovery - which ultimately led them to us. They had no idea that we were living in Kuranda, so once we had made contact they invited us over to collect the spider. Oddly this spider was sharing the nest box with a Brown Huntsman (Heterpoda jugulans), a Red House Spider (Nesticodes rufipes), and a nest of Sugar ants (Camponotus sp).

Only two other specimens have turned up to our knowledge since 2006. One collected near the Clohesy River appeared for sale online for $500 some months after the original discovery - we don't know what happened to that specimen. Another was found dead inside a house in Mossman after a pesticide treatment last year - photos were sent to Melbourne Museum for verification.

We now know that this species extends from Cairns, through Kuranda up to Mossman, and west as far as the Clohesy River. We suspect that the reason for so few specimens being found and that it has gone unnoticed for so long is due to a very secretive lifestyle - perhaps a canopy dweller that rarely comes close to the ground.

The stunning spider as photographed this afternoon.

Assassins on the prowl

We have spent the last three months filming a TV series on predatory bugs, and some of the predators we have been working with are the assassin bugs. They are incredible insects that hunt by stealth, then stab their victims with their long proboscis and paralyse it within seconds.

Watching them hunt is amazing. Once they detect prey they will approach it with such caution that they hardly seem to be moving at all. All the while they keep tabs on their intended prey with extremely long mobile antennae. Sometimes the strike is rapid, but other times they try to sneak in a little lethal injection without the victim noticing. Once the victim notices the little sting it is all but over. The assassin bug then feeds on the victim via its proboscis, and discards the empty husk when finished.

 

A delicate orange assassin bug from our garden. This species is a ready flyer.

The same species feeding upon a grasshopper.

One of the giants, a Bee Killer Assassin Bug Pristhesancus plagipennis found about 10 minutes west of Kuranda

A close-up of the proboscis of Pristhesancus plagipennis. This species can capture very large insects.

Mini ambush hunters

Both these tiny spiders are hunting in our front yard. The yellow crab spider (Thomisus spectabilis) is a flower-top hunter. This species waits in ambush for flower-loving insects. They can catch prey up to the size of a honeybee, many times their own size.

Crab spider, Thomisus spectabilis. Crab spiders are so called because of their ability to move sideways.

The Triangular spider (Arkys sp.) is another ambush hunter which sits and waits upon leaves for passing prey. Although these two spiders are unrelated, they both share similar adaptations to assist them to snatch and hold their prey.

Triangular spider, Arkys lancearius

Nocturnal visitor

We were returning from a recent night walk, and had practically reached our front gate when we had a chance encounter with another invertebrate lover. This one, a Striped Possum (Dactylopsila trivirgata), prefers to eat the invertebrates it finds. Striped Possums have an elongated 4th finger and use it to hook out wood eating grubs from within the trees. They also use their teeth to tear open the timber to expose the insects. The diet of this species is not just confined to insects, they also feed upon fruits, leaves, and will dine out on the honey of native bees if they are lucky enough to find some.



The Striped Possum just opposite out driveway. It dissapeared very quickly after this photograph. 



Bright orange amongst the green

It seems that being bright orange and yellow is the recipe for success in the rainforest for several species of Australian huntsman spiders. Compared with the grey-brown camouflage colouration of most of the southern species in the Sparassidae family, many of the rainforest huntsmen are simply stunning.

This week I have encountered two brightly coloured species in the genus Beregama. Beregama cordata, the Fireback Huntsman, and Beregama aurea, the Golden Huntsman. The latter is a huge spider and is considered the second largest species of huntsman in the world behind Heteropoda maxima from Laos.

Previously in this region we have encountered the orange/yellow Sunburst Huntsman and the Tiger Huntsman, both of which are undergoing classification.

Why bright orange? As juveniles these spiders are quite dull and cryptic, but they progressively adopt the brighter colouration as they grow. As adults, they often stand out like beacons within their habitats. Whether the colours are just for warning away predators or for some other purpose I cannot say. It does not seem likely that it is for courtship purposes as the vision of this group is quite limited, and courtship seems based upon pheromone detection and tactile interaction.

 


A huge male Beregama aurea, 4km west of Kuranda

 

A female Beregama cordata at Cape Tribulation

A Sunburst Huntsman from Cape Tribulation in 2006

The female Tiger Huntsman we found near Cairns in 2006. (This was the first record of this species and is currently at the South Australian Museum awaiting description)

Spider identified and mantispid emerges

We have identified  the crab spider as Poecilothomisus speciosus (thanks Colin). It is the sole member of the genus in Australia, and is only found in north eastern Queensland. We are not sure why the Australian spider has been placed in a genus by itself, whilst the related overseas species are all members of Platythomisus - had me confused.

Today the eggs hatched but only a handful of tiny spiderlings emerged from the egg sac. The reason for this was because an invader had also been occupying the egg sac - a mantispid.  Mantispids are mantis-like Neuropterans and some species select spider eggs as food while they are in larval form. Mantispids use two strategies to access spider eggs; some larvae find an egg sac and burrow in through the silk, while other species hitch-hike upon the female spider and enter the egg sac as it is being constructed. We are not sure which strategy this particular species used, but it was successful.

The mantispid shortly after emerging from the egg sac.