The Shade Skink, Saproscincus basiliscus, looks like any of a number of small skinks you see amongst the leaf litter. It measures about 4.5 cm snout to vent length. What is different about it is that it always sleeps on leaf surfaces about 50 cm from the ground. There must be some protective value in this strategy, but what it is I have not determined. Perhaps, there are ground marauders that it avoids with this technique. What id does do is to keep it out of the realm of the Cane Toad, Bufo marinus, which patrols the ground each night in search of anything it can subdue. Small lizards are often eaten along with frogs and a wide variety of insects.
A word about the big boys. The Lace Monitor,Varanus varius, is a common resident in rainforests. It is a member of the group of lizards known in Australia as "goannas". This is a perversion of the word "iguana" so-called by the earliest Australian settlers. This lizard is at home on the ground as well as in the trees where it feeds on anything it can subdue. Birds, lizards and small mammals are taken. It lies in wait and unsuspecting Musky Rat Kangaroos bumble into the jaws of these monsters. A full grown Lace Monitor can be over 2.1 m long and have jaws measuring 12 cm. There are lots of stories about Lace Monitors. They often hang around campgrounds where they learn that there is food. They have an excellent sense of smell and if they get a whiff of something they want, almost nothing can deter them. I have seen them enter tents and tear the place up looking for food. I have heard stories of them taking sandwiches from the hands of startled picnickers. They have relatively poor eyesight and have been known to "run up a person" when danger threatened probably mistaking the person for a small tree. Our big Monitors have blunt tails. I was fortunate to see why one day when my camera was not at hand. The Brush Turkeys hate these lizards because they will dig up their mounds looking for eggs. Once they start, they are usually not deterred. When the turkeys find a wandering Monitor, they bite the tip of the tail always staying out of the range of the mouth and claws that would surely spell their end. When the tails are long and slender, pieces are bitten off. The scenario ends when the lizard runs up a tree. The turkeys can fly but I guess they feel less threatened when the lizards are treed.
(Gary Wilson photo) (Gary Wilson photo) (Gary Wilson photo)
The Northern Leaf-tailed Gecko, Saltuarius cornutus, is probably found on our property but I have not seen it--or heard it. These large lizards (14 cm snout to vent length!) live in trees and emerge at night to sit and await unsuspecting prey. They seem to prefer geckos of other species. They have been found around homes where they prey on the Asian House Gecko. I have seen and heard similar species in Borneo where they do much the same thing. They are said to be quite aggressive if encountered in nature.
A most unusual gecko! Imagine our surprise to find this structure at the Mareeba Wetlands, a marsh-lake habitat just to the north of Mareeba. A plaque states this stainless steel gecko was donated by a Japanese sculptor who places one of his creations wherever he finds native wild rice growing. Unusual to say the least.
Nothing has been said to date on the lizard fauna in this blog. Kuranda has a nice selection of lizards ranging from some very small species to intimidating giants. Of interest to readers in the northern hemisphere are the different families that occur here that you won’t find in North America. Where the Iguanidae are well represented in the New World, we have no species in this family here. But we have “look-alikes” that you would easily mistake for iguanids that are in the family Agamidae. These are sometimes called “ecological equivalents”. But this should be used only loosely as we don’t know enough bout the intimate details of the life histories of these species to be certain they are really ecologically equivalent. Suffice it to say when comparing Old World and New World species that there are some that display convergent evolution, that is in some way they resemble one another but are not related. We see this in all groups, not just lizards.
The Mountain Devil, Moloch horridus, of the Australian dry interior resembles a North American Horned Lizard but is an agamid, not an iguanid. However, like the North American examples, it feeds on ants. Similarly, our Boyd’s Forest Dragon looks like an American iguana but is unrelated. It is another agamid.
This Basilisk resembles Boyd's Forest Dragon to some extent. It is a member of the Iguanidae while the BFD is an agamid. I have been following a young lizard that returns from time to time to collect insects with me at the lights. It frequently spends the night on an adjacent palm frond but by first light, it is gone. I can tell it's the same individual because of its markings.
As a young lizard a couple of years ago, it would come to the lights and sometimes scamper up the sheet eating beetles and moths as it made its way up.
Geckos are more often heard than seen in the northern Australian tropics. The Asian House Gecko occurs in and around dwellings. It has been moved around the tropics by commerce. In the house it performs a vital service in catching insects and spiders. It has a call that our Cockatiel imitates. They do this as a territorial display and in courtship. These lizards are wary and are not easy to approach even though they live in close contact with humans. They spend the daylight hours behind pictures or in drawers. Their eggs can often be found in folded clothing or behind books. Quite a successful lizard as far as adaptation is concerned. The gecko above is only similar to the Asian House Gecko. It is a native species from the Daintree region just north of Cairns.
Skinks are not common lizards in North America but they are relatively common in Australia. You can find several species at any given locality. We have several at Kuranda. The smaller skinks can be approached and easily photographed. Carlia rubrigularis is aptly named. It can be seen on the ground in the sunshine. It seems common and is probably the food of many predators. This species is endemic to coastal rainforests. Egernia frerei, the Major Skink, is a large fellow with northern affinities. It has been found in southen New Guinea. It is shy and seldom seen for more than a few minutes. We think we see the same individual each time but we can't be sure. It has to be wary because of the number of potential predators ranging from Brush Turkeys and Butcherbirds to other lizards and snakes.
A Few More Beetles Longicornes or Long-horned Wood-borers, Cerambycidae The larvae of cerambycids live is wood, mostly dead or dying wood. Of course, a rainforest provides ample habitat and this group is represented by dozens of species some small and others very large. The natural histories of most species are as yet unknown. And it is surprising that a group of such economic importance, and of appeal to collectors, Australian as well as foreign, that comprehensive guide to species exists. Meet Rosenbergia megalocephala van der Poll, quite a mouthful but a large an impressive longicorne that infrequently comes to our lights. Platymopsis nigrovirens is an attractive species that sits on twigs during the daytime in a cryptic position. Other members of the Lamiinae, like the one below, do the same. This is one of many lamiine cerambycids. It is a good example of protective coloration. This species of Phoracantha has a most peculiar resting stance. On a tree trunk it looks like anything other than a beetle.
One of many unidentified species that frequents the Kuranda rainforests. This prionine will be familiar to northern readers as both Prionus and Ergates are commonly found in coniferous forests where the larvae bore in dead wood. In Australia also there are a number of species but their taxonomy is still to be done. They always attract attention when the buzz into lights. They have powerful mandibles and only the most adept of the Black Butcherbirds can make a catch without being injured. They seem to prefer these beetles over others at the lights. This may be just a reaction to the large size of the beetles but it may be something more. These beetles may be more nourishing than may of the others.
In the first volume of his monumental 5 volume series on the Australian Weevils, EC Zimmerman states that “... the Australian weevil fauna contains more species than all of the Australian mammals, birds, reptiles, fishes and amphibians combined plus various invertebrate groups.” He felt the Australian fauna probably contained 1000 genera and up to 8000 species. Weevils are almost everywhere, in almost all terrestrial habitats.
There is a nice selection of species in the rainforests but you have to look for them. Many are in decaying timber, others in the leaf litter and in developing seeds and fruits. Most are very small and go unnoticed. A nice sampling comes to the lights and a few are presented here. While the majority of species are in the weevil family proper, the Curculionidae, there are many in related families. Like the Brentidae and the Anthribidae.
Anthribidae The Fungus Weevils
If cryptic coloration fascinates you, try to find the Dendropemon weevil in this shot. The family is best developed in areas of high rainfall. This is because they may feed on fungus. as Zimmie points out we really don’t know because the observations just haven’t been made.
These odd weevils are represented in Australia by a few genera and not too many species. They seem to be primary wood-borers, boring in freshly felled timber where they probably feed on fungi. However, some are known to bore in living tissue and there is a cadre of species that live with ants. Ithystenus hollandiae (Boisduval) comes to lights in the wet season. Males joust with one another on logs. They guard egg-laying females as well.
Curculionidae True Weevils or Broad-nosed Weevils The majority of species reside in this family and range in size from the small species you find in birdseed or cereal products to some real giants in Australian woodland and heaths. The long-nosed Weevil, Sipalinus gigas granulatus (Fabricius) is a large and rock-like species that flies to the lights occasionally. It has long legs used to grip bark and twigs. In nature it often occurs in groups on suitable logs. the larvae can cause considerable damage to harvested logs awaiting processing.
The New Guinea Sugarcane Weevil, Rhabdoscelus obscurus (Boisduval) is a pest of sugarcane and was probably introduced into Australia. Unfortunately for those who like to breathe clean air, the burning of the sugarcane prior to harvest probably helps to destroy the weevils. This weevil also attacks and kills palms. It is of concern to homeowners and horticulturists because of the devastating effects it can have on ornamental palms. By the time growers notice the problem, it is too late. The larvae tunnel in the tissues and eventually kill the palm.
Leptopis malefictus (Lea) flies to the lights on the odd occasion. It is in a large genus with species all over the country. It is often associated with acacias.
Zimmerman, E. C. 1993. Australian Weevils (Coleoptera: Curculionoidea) Volume III Nanophyidae, Rhychophoridae, Erirhinidae, Curculionidae; Amycterinae, Literature Consulted. CSIRO, American Entomological Society, pp 1-854.
Zimmerman, E. C. 1994. Australian Weevils (Coleoptera: Curculionoidea) Volume I Orthoceri Anthribidae to Attelabidae The Primitive Weevils. CSIRO, American Entomological Society, pp 1-741.
Each morning there is an array of beetles of many species at the light sheet. The species component varies with the season and flowering and fruiting of the vegetation. As with all insects, each has a particular biological story. Many we are yet to unravel. Here are a few highlights.
Many scarabs come to the lights, some apparently from great distances. Here we have the Grey-backed Cane Beetle. This large scarab is a pest of sugar cane and is responsible for the intrduction of Australia's greatest pest since the introduction of the "white"man', the Cane Toad, Bufo marinus. This beetle attacks sugar cane from beneath. The grubs feed on the roots causing considerable damage to the crops. Cane toads would never encounter the grubs since they only burrow in the colder months to sleep. They would only encounter the adults on a chance basis since the adults are airborne most of the time and seldom come to ground. In general, one of the least likely places you would encounter a Cane Toad would be in a cane field. They avoid dense plantings. This is true to some extent o the rainforests. They only occur there when times are tough and food is scarce. Normally you would not encounter Cane Toads in rainforests.
The Grey-backed Cane Beetle Dermolepida albohirtum (Waterhouse)
Green scarabs, like this one, Anoplognathus punctulatus, are frequently found on the light sheet. Interestingly, they are not picked off by the several species of birds that arrive every morning at day break for their breakfast. Are they distasteful? Or is the search image on the sheet one that the birds just don't recognize?
One of a number of green scarabs found at lights in the wet season.
Anoplognathus aureus is one of a number of species called Christmas Beetles. This little jewel apparently deceives predators by appearing to be a spot of reflected sunlight on a leaf. I took this photo of a scarab similar to A. aureus in Costa Rica. It is unrelated and is a great example of convergence.
The Rhinoceros Beetle Xylotrupes ulysses australicus (Thomson) is common along the coast from Sydney to southeast Asia. They always attract attention when they are found at lights. Males have an elongated horn that is used in jousting with other males. These beetles are often kept as pets in Asian countries. They are easy to keep. Adults feed on a variety of fruits and the large grubs can be raised on leaf litter with a generous supply of dry dog biscuits.
Tiger Beetles (Carabidae; Cicindelinae) are usually encountered along ocean shores or along streams. There are a few, like Distipsidera undulata, that occur on tree trunks where they hawk passing insects. This one is an infrequent visitor at the light.
Rhipiphorid beetles are special--but they don't look very special. Females are usually wingless and lack mouthparts. This suggests something special. They are parasites of other insects. This one is probably Rhipidioides and is probably a parasite of cockroaches, and probably those in the family Blaberidae. [If you're into cockroaches, this is the place. I've found about 70 species here, mostly in the Blattellidae]. The first instar is a triungulin larva that travels around at a fast rate looking for the appropriate host. Hosts of other genera include wasps, bees, flies and some other beetles.
Melitomma sp. is a member of the Lymexelidae, another beetle family with somewhat peculiar habits. The larvae are wood-boring but feed not on the wood but on the ambrosia fungi that grow on the walls of their burrows. Females have pouches near the end of the abdomen where they store the fungi that are later deposited with the eggs. When the eggs hatch, the young larvae "infect" the walls of their new burrows with the fungi that grow and nourish them.
Longicorne Beetles (Cerambycidae) range in size from beetles a few millimetres long to some giants over 70 mm. The larvae bore in wood, roots and other plant material. It is a large family and being in a rainforest you would expect an impressive array of species. And such is the case.
Coptocercus biguttatus is one of many in the genus. They are distinctively marked and come to lights or can be found on flowers during the daytime.
Many longicornes assume unusual patterns at rest. This is to deceive potential predators. Being wood borers, most species possess formidable mouthparts. It is always intriguing to watch the assortment of Black Butcherbirds, fantails, robins and the inimitable Brush Turkey, attack beetles in the morning. One bite from the beetle could snap off a toe or remove the tongue of the bird, but I have never seen a mishap. The birds know how to approach the resting beetles and they take precautions.