Hercules update

We are currently raising some Hercules Moth caterpillars. They hatched out on the 26th of May and one has pupated today, a larval period of 81 days. The growth rate of the caterpillars has been relatively slow given the cooler conditions we have experienced over the recent months. 

A caterpillar emerging from the egg on the 26th May.

24 hours after hatching and the larvae are feeding voraciously and already filling out.

At 24 days old the larvae are substantially larger, but still white in colour.

By 40 days they are pale green in colour and becoming very large caterpillars.

Day 74 – what a whopper!

Silken weaponry

A drama unfolded on our ceiling recently which highlighted the power of silk that some spiders use. A Red House Spider (Nesticodes rufipes) capture and killed an Asian House Gecko (Hemidactylus frenatus) much larger than itself, and it did so using silk as its major tool.

A Red House Spider (Nesticodes rufipes) in the process of capturing an Asian House Gecko (Hemidactylus frenatus)

Several hours later and the gecko has seccumbed to the spider's venom and the spider has begun feeding.

This spider belongs to the family Therididae, which also includes well known species such as the Redback and Black Widow. Many of the spiders in this family utilise a particular snare system that enables them to capture very large prey. One of the key parts of the snare is high tension trip lines that are beaded with blobs of liquid silk. When prey makes contact with these lines it is bound by the glue-like silk and becomes tethered. Any struggles often result in it making contact with more lines, and subsequently in more trouble. At this point the spider descends from the scaffold of silken threads which support the trip lines, and using its long rear legs begins to bind the prey with lines coated with the glue-like silk. For most animals, there is little chance of escape from here on. Only when the prey is safely manacled with dozens of silken lines does the spider venture close enough to bite its victim, which begins the chemical onslaught inside its body.



A Redback (Latrodectus hasselti) in the process of binding a large Tenebrionid beetle.

A Redback with a bound up huntsman, over 10 times its own body weight.

Evening...Brown

This is an Evening Brown Butterfly, Melanitis leda, a species most active in the early morning and late afternoon. We have seen many of these butterflies around, but this one ended up inside so I decided to take a few photos. I was quite taken by the comical appearance of the face in particular.

The species has excellent camouflage while sitting within dry leaf litter, usually spending periods of inactivity sitting motionless on the forest floor. It has a distinct wet-season and dry season colour form, this is obviously the dry-season form.

Two-spined Spider

This is Poecilopachys australasia, a small orb-weaver aptly named the Two-spined spider. This species builds a small orb-web at night and dismantles it at dawn each day, presumably to avoid diurnal predators. She has the remnants of last night's web still in her chelicerae.

This is a young female, her colours will become more vivid as she matures and her abdomen will be less hirsute. She is currently in our backyard only metres away from me now as I type - hopefully she survives to adulthood and if so, I will post another blog about her then.

Would you like peppermint with that?

This is Megacrania batesii, the Peppermint Stick Insect. It is the only member of the genus in Australia, and has a specialist diet feeding; only on Pandanus tectorius in the wild. Despite the plant being relatively widespread in north Queensland, M.batesii is confined to only a few areas; Cape Tribulation, Mission Beach and Innisfail.

These insects spend almost their entire lives sitting longitudinally along the pandanus leaves, which they feed upon periodically. Their common name is derived from their characteristic chemical defence. They have glands behind the head that can direct a considerable jet of a peppermint scented chemical at anything harassing them. I have had it on my hands countless times without issue, but getting it your eyes is another matter entirely. For a small predator, a blast of this at close range is bound to make it hesitate. The major component of the chemical is Actinidine which oddly enough is very similar to nepetalactone, the active component of Catnip.

The ducts to the chemical glands are located on the pronotum immediately behind the head. They seem to have an ability to direct the spray in the direction of the threat.

A close-up showing the turret-like openings that direct the chemical blast.

If you are interesting in keeping these or other fascinating species of stick insects visit Minibeast Wildlife's website.

Tiger, tiger, burning bright.

This is a gravid female Tiger huntsman, the undescribed species we have maintained both at Melbourne Museum and at home since finding a single gravid female in 2006. Since then we have bred several generations of these superb spiders, but all are related as they originated from that one female. This individual presents the first opportunity to mix new genetics into the pool in six years. We found her near our home in Kuranda and had a male sent up from Melbourne to pair up with her. They mated on the 12th of January this year, and all appeared to go well.

If she produces an egg sac it will take around 40 days for the young to emerge. We intend to send some spiderlings down to Melbourne Museum if everything goes to plan.

We have been lucky and have found two individuals within the last year. The second actually fell out of a tree and landed beside me. It was bleeding from the stubs of three missing legs and had obviously just escaped the clutches of some sort of predator. She has now moulted twice and has regrown her missing legs, but she has still two more moults to go until she matures.

Since 2006, we are only aware of seven recorded specimens of this species. Unfortunately the specialist Australian Sparassid taxonomist that began work on them retired recently, which is why the species remains undescribed. I have been discussing this with other arachnologists in the hope that someone will pick it up.

For more information about Australian huntsman spiders visit Minibeast Wildlife's page.

Female Hercules

A little while ago we raised a Hercules Moth caterpillar until it pupated. We suspended the cocoon in the kitchen (as you would), and a couple of day ago we awoke to find a giant female moth hanging quietly from it. We allowed her to hang undisturbed for 24 hours, and then took her out to the species' host plant Omalanthus populifolius within the backyard. We were hoping that she might attract a male, but she immediately began to lay eggs. We assume these initial eggs will be infertile (unless a stealthy male managed to sneak into the kitchen). By the following morning she had left the tree.

The face of the female Hercules Moth. The antennae are very impressive, yet those of the male are larger still.

She will only have a life-span of less than two weeks; she will not feed but instead survives only on the fat stores within her abdomen. Hopefully she can attract a male if there are any around at present, as there is no shortage of food plants locally for any resultant caterpillars.

The female Hercules Moth, Coscinocera hercules hanging in a Bleeding Heart tree in our yard

Laying eggs on the stem

The sticky red substance binds the eggs together and onto the plant.

The Hercules Moth, Coscinocera hercules is the largest moth in Australia with a wingspan of up to 270mm.