Velvet Assassins

In the last couple of weeks we have encountered several velvet worms (Onychophora); primitive predatory invertebrates which are though to have originated over 500 million years ago. They are believed to be the forerunners to arthropods, but unlike today's arthropods, the velvet worm has no hardened exoskeleton.

This velvet worm is about 30mm in length

Its skin is composed of a membrane of dead cells covered in tiny hairs, which are in themselves covered in tiny scales that give it the appearance and feeling of velvet. These hairs function in a sensory capacity and respond to touch. This covering is also water-repellent, which makes it perfect for living in a very moist environment – seconded by its inability to regulate water loss. It is therefore very easy for a velvet worm to succumb to desiccation, and as such, it is only found in tropical and temperate rainforests.

A close up of the face; a 'nozzle' for spurting the sticky liquid can be seen just beneath the eye.

One of the most remarkable things about this minute predator is its method of attack. It shoots twin streams of a sticky liquid at its prey from nozzles either side of its mouth. The liquid transforms to a bonding gel on contact with the prey as a chaotic mix of proteins within the substance combine and react. The result is dramatic, the prey is usually securely bonded to the surface it is on, and all the velvet worm needs to do is wander up and consume it at its leisure.  The one in the photo below actually shot glue on my finger when I first picked it up. I noticed an immediate chilling sensation as the liquid hit and reacted; I then spent a minute or so picking off all the sticky material!

Elusive Arachnids

After years of looking and hoping I have finally encountered some Australian Amblypygi. This group of bizarre looking arachnids are known as ‘whip spiders’. They superficially resemble true spiders but are very different in many ways. Australia has a handful of species in the tropics, but they are neither common nor easy to find.

Charinus pescotti from Kuranda

Amblypygids are found throughout the world, primarily within tropical and subtropical habitats. Australian Amblypygids are relatively small compared to some of their overseas relatives. This species Charinus pescotti only grows to a body length of around 10mm, with a leg span of around 25mm. The giant African Euphrynichus amanica can attain a leg span of up to 400mm.

Amblypygids have two distinct body parts and four pairs of legs, so at a glance they are a little spider-like, but that is where the similarity ends. The abdomen is flattened and has 12 segments, and they lack spinnerets and cannot produce silk. The first pair of legs are antenniform; very long and delicate compared to the other legs, and extremely sensitive to chemical and vibrational cues.

The first pair of legs are antenniform and are important sensory tools.



One of the most striking features of these animals are the palps. They are raptorial; they have become adaptations to snatch and impale their prey with. The palps have rows of spines on the inner edges, and while not in use the palps are tucked up in front of the face giving them a fearsome appearance. The chelicerae (mouth parts) are fang-like and are similar to those of mygalomorph spiders, but Amblypygids lack venom. Prey, usually insects, is captured with a lighting fast strike using the palps. The animal is the drawn back to the front of the Amblypygid where the chelicerae begin to tear it open while digestive juices are expelled into the opening. The resultant semi-digested fluids are sucked back up in the same manner as spiders do.

The spiny raptorial palps are held in front of the face when not in use.

A true leaf insect

For those interested in Australian phasmids there are several species on the must see list. Up there would be such species as the Lord Howe Island Stick Insect (which was considered extinct until 2002 when it was rediscovered on Balls Pyramid, a small rocky outcrop off the coast of Lord Howe Island. Another on the list would be the true Australian Leaf Insect (Phyllium monteithi). This species is known from only a handful of male specimens, which have been found between Innisfail and Mossman. A female was photographed in the Cairns Botanic Gardens, but the specimen was not collected. Recently we were lucky enough to encounter a live male which turned up on David Rentz's light sheet.

Leaf Insects are truly masters of disguise, both sexes are broad and flattened like leaves as juveniles, but only the female remains so as an adult. They are believed to be canopy dwellers which explains the lack of encounters, and may feed on the foliage of Cryptocarya mackinnoniana. They will also feed upon Guava which this specimen certainly did. When we first moved to Kuranda we planted several Guava trees just in the hope of attracting these illusive insects.

The genus Phyllium is represented by over 30 species throughout southern Asia. The biggest, Phyllium giganteum is a common representative within live insects displays around the world. They are also commonly kept by insect enthusiasts throughout Europe and the USA.



The mature male Phyllium monteithi. Males have fully functional wings and are excellent flyers.



Peeking over a leaf - note the extremely hairy antennae.

The underside of the abdomen reveals the segments hidden by the wings when viewed from above.

   

This specimen readily fed upon Guava, one reason we inspect all Guava trees we see with great interest.

A close-up of the male feeding.

While most male phasmids have some flight capability, this one would readlily take to the air and was quite agile on the wing.

Fruit-piercing moths in abundance

The last few weeks has seen the appearance of a huge number of moths with a considerable diversity being attracted to our lights and entering the house at night. One of the most abundant are the fruit-piercing moths from the family Noctuidae. Many of these moths are quite large and are often adorned with spectacular colours and markings.

These moths are attracted to fruits both on and off the tree. The feeding habits of these moths do not endear them to orchardists due to the damage they cause. I recently observed a tree fruiting at Crystal Cascades which had in excess of twenty of these large moths of various species feeding on its fruits. A large adult Nephila pilipes had her web set-up within the branches of the same tree, and was reaping obvious rewards. At the same location I found one of the largest caterpillars I have ever seen, complete with very convincing eye-spots. The caterpillar is the larva of one of the largest moths in this group, Phyllodes imperialis.

Eudocima iridescens, one of the fruit piercing moths that appeared at our home

The spectacular Phyllodes imperialis caterpillar

The eye-spots and apparent teeth are enough to startle many would-be predators.

Monster Bug Wars

The TV series we worked on from October to the end of January has recently started going to air in the US on the Discovery Science channel. We were contracted by Beyond Productions as invertebrate specialists and wranglers. The program is quite educational and examines the upper echelon of invertebrate predators, and reveals their adaptations and abilities within their various natural habitats.

Our role was to recreate the habits (sets) for the camera, and of course supply and wrangle around 60 species of invertebrates in order to film a wide range of natural behaviours. Each segment culminates in the pinnacle - the predation sequences where two predators meet. All the match-ups are those which would naturally occur in nature, but getting natural behaviour to occur on cue in front of the camera isn’t as easy as it sounds. It was a painstaking and patience-testing job, 10 hours a day for 3 months. For the most part there were just three of us on set; the DoP (Director of Photography) Malcolm Ludgate, camera assistant Mylene Ludgate, and myself (Alan). It was shot in full HD, and for some sequences we used two cameras - a specialised high speed camera which we cranked up to 2000 frames per second at times. (This camera was from the Myth Busters set, and came complete with shrapnel holes in the back of it). Some of the sequences we recorded with this camera gave us incredible insights into the behaviour and tactics used by some of the predators - things you would simply miss or misinterpret watching them at real speed.

The final product includes amazing imagery, some stunning CGI, music and an array of sound effects. Although the program style may not appeal to everyone, it is already gaining a substantial following in the US, and hopefully not only raising the profile of these often overlooked animals, but also providing the audience with a sense of appreciation for them through admiration of the incredible abilities these minute predators have.

One of the rainforest sets, surrounded by lights and two HD cameras.

Malcolm operates 'the probe' while I get the stars in place. The probe was  $100K lens kit which allowed us to get amazing up close imagery with holywood style tracking moves.



Preparing a White-tailed Spider to meet up with a Black House Spider.



One of the complete segments - a Bullant meeting up with a Redback.

Micro-scavengers

I spotted a tiny gathering on a leaf in our front yard recently which tweaked my interest, and I couldn't resist snapping a photo. It consisted of a Green Tree Ant (Oecophylla smaragdina), or part thereof, and a group of tiny ants (probably Monomorium sp.). Green Tree Ants are one of the most dominant scavengers in this region. Colonies can be huge, occupying and completely dominating multiple large trees and the surrounding forest. They can be seen carting away all sorts of animals, both complete and dismembered. I once witnessed them carrying a small python up a tree in the Northern Territory.

In this scene however, the tables are turned. Tiny ants carry away the relatively huge head of Green Tree Ant worker. In reference to food chains, you often hear the saying 'there's always someone bigger'. Ecosystems though are complex and not linear like a chain, but interwoven like a web. In this case it would be more apt to say there's always someone smaller...

Tiny ants, barely 2mm long cart away a nice morsel for their colony; a Green Tree Ant head.

Monster Spider!

We awoke to find this massive spider on the lounge wall this morning. It is clearly the biggest spider we have ever seen. We think it is the elusive Heteropoda aperirefollis; a single huge specimen was collected in April 1903 by biologist H.G Whells in 'northern Australia' - no other locality data available. The species has not been recorded since.

We also suspect that this big female arachnid is the reason for the disappearance of all the geckos in our house over the past week, and our neighbours’ kitten.

Unfortunately, just before midday today, the spider chewed its way through the plastic container and has disappeared. We are hoping it shows up again, but it may be another 12 months before we see another specimen like this one.

Deanna sizing up the spider before capturing it.

'We're gonna need a bigger boat'.