Tuesday, 30 September 2008

A Darkling Beetle

.....Saragus costatus

Whilst in hot pursuit of a small but agile skink, I was removing a few rocks among which it had crawled. My attention was then shifted to the interesting looking beetle you see photographed below. It is 15mm in length and I believe it to be Saragus costatus, one of the Darkling beetles of the Tenebrionidae family. As was the case with this one, these beetles are often found under rocks or among leaf litter. Most likely, it was laying low, waiting to come out at night to feed. Most of the Tenebrionids feed on rotting plant and fungal material although the larvae of this particular genus are root feeders. Along with several other genera they are listed among the False Wireworms which, coincidentally, I mentioned here just a couple of days ago. Another coincidence is that I last saw this species almost a year ago to the day and only a few feet from where this one was located.

Tenebrionidae is a very large family with over 1500 species in Australia. "The Catalogue of the Insects of Tasmania" lists 82 species here in Tasmania including the well known pest of stored grain, the Mealworm. My first post on this blog showed the full life cycle of the Mealworm Tenebrio molitor. It can be viewed here.


(Click Photos to Enlarge)
Saragus costatus - Dorsal View


Saragus costatus - Frontal view


Saragus costatus - Ventral view


Monday, 29 September 2008

Gunns Plains Cave

Gunns Plains Cave is located 20km south of Ulverstone. This limestone cave was discovered in 1906 by Bill Woodhouse while on a hunting trip. There seems to be two versions of the story. One that a possum eluded him by going down a hole into the cave and another where his dogs fell into the cave. Of course it's not hard to imagine that both are true if the dogs were chasing the possum. Since that time tourists have come from far and wide to witness the spectacular limestone formations. The area was declared a state reserve in 1918 and access was improved early on by making a new entrance through the side of the hill and building a concrete stair case which is still in use.

The cave has been cut by an underground river which still flows through it today. There are a good variety of cave formations (speleothems) including what is claimed to be the the largest shawl formation in the world.

When I was last there one cave spider was pointed out to me although it was in a crevice so it wasn't easy to see and was impossible to photograph. Easier to see were the threads from Glow Worms, Arachnocampa tasmaniensis, hanging from above. Other wildlife that has been seen within the cave includes the platypus and the Tasmanian Giant Freshwater Crayfish, Astacopsis gouldi (the worlds largest freshwater invertebrate).



(Click on Photos to Enlarge)

Gunns Plains Cave - The Golden Fleece



Gunns Plains Cave


Gunns Plains Cave


Gunns Plains Cave - Shawl Formation - Claimed to be the largest in the world.



Gunns Plains Cave - note the stairway for scale


Arachnocampa tasmaniensis - Glow Worms at Gunns Plains Cave




Sunday, 28 September 2008

Wireworms

.....The Larval Stage of the Click Beetle

These slender, hard coated, ground dwelling insects are the larvae of Click beetles (Elateridae). Many of them feed on roots and thus a few are considered agricultural pests. Some of the Elaterids are even carnivorous although I'm not aware of whether any of the Tasmanian species are in this category. The "Catalogue of the Insects of Tasmania" lists 38 species from 4 subfamilies. They are slow to mature and some species spend many years in the soil before pupating and emerging (usually Jan/Feb).

The Wireworm in the photographs below was found in my backyard yesterday. While I did not measure it, I would estimate it to be around 12mm - 15mm in length.

(Click on Photo to Enlarge)
A Wireworm



True or False?

The larvae of the Tenebrionidae are also rather wiry and are often referred to as False Wireworms. So how can you tell if you have a true or false wireworm? For one thing, False Wireworms are more cylindrical and are fast moving. The ones I've seen have wriggled quite vigorously when disturbed. There are a few features that will help to identify a True Wireworm. The head will be dark brown. They have a single proleg under the last segment. This segment also has a flattened shield, known as the anal plate, with serrated edges.

(Click on Photos to Enlarge)
Detail of anal segment


Ventral View


Detail of head and thorax - ventral view



A typical adult Click beetle


Saturday, 27 September 2008

Some Introduced Snails and Slugs

.....Terrestrial Molluscs

I came a across a Great Yellow Slug, Lehmannia flava, in the veggie garden today (not an unusual occurrence) and I though I'd post it here along with some other introduced molluscs which inhabit my backyard. I think it was Bill Mollison who said something to the effect of, "You don't have a slug excess, you've got a duck deficit!" Well as it happens we do have a large population of chickens and ducks in the yard and by and large they do a good job of keeping the numbers down. However there are always the ones that escape detection. Here are a few of them.


(Click to Enlarge Photos)
Cochlicella barbara - Small Pointed Snail


Oxychilus alliarius - Garlic Snail



Helix aspersa - Common Garden Snail


Lehmannia flava - Great Yellow Slug


Lehmannia nyctelia - Striped Field Slug



Friday, 26 September 2008

A Jumping Spider

.....named Groucho



All I can say about this one is that it is a Jumping Spider of the family Salticidae, and that it certainly lives up to it's reputation. With a total body length of only around 5mm-6mm it managed an amazing jump of about 40mm - 50mm in an effort to escape my camera. It succeeded too. It landed down a deep crevice in a tree stump where I could no longer see it.

In the absence of a more precise name I've decided to call him Groucho. If you can't see any resemblance then you may need to compare photos #3, #4 and #5 :-)

Edit: I've since found that this is Opisthoncus polyphemus


(Click Photos to Enlarge)

A Small Jumping Spider - Opisthoncus polyphemus


A Small Jumping Spider - Opisthoncus polyphemus


A Small Jumping Spider - Opisthoncus polyphemus
Do you see the Grouch Resemblance?


For those with no imagination :-)


... and of course the real Groucho Marx


Thursday, 25 September 2008

Here be Dragons

.....Mountain dragons - Rankinia diemensis (J.E. Gray, 1841)


While up the back of the block today I came upon a dragon. No not the fire breathing kind; just the humble Mountain Dragon, Rankinia diemensis. Of Tasmania's 17 lizard species this is the only one which is not a skink. It belongs to the family Agamidae and it has the most southerly distribution of all the lizards in this family..

You can get quite close to a Mountain Dragon if you move slowly. If they run they will only go a short distance and then stop again, pretending you can't see them. It works too as sometimes you can't see them because they blend in so well among leaves and sticks. I did manage to get close enough to one today to actually stroke it and it did not run.

While following it around trying to get a decent shot I suddenly noticed, while looking through the lens, that there was in fact a pair of them. A breeding pair? I don't know, you be the judge. It is said that a female is larger than a male but has a proportionally smaller head.

They are found in the north and east of Tasmania, in dry forest and heathland as these areas are more open to the sun. Their diet consists of ants and other small invertebrates. At my place Mountain Dragons are quite common (there are certainly enough ants for them) although these are the first I've seen this spring.

In late spring and early summer they lay from 2 to 9 small eggs (15mm) within a short burrow.


(Click Photos to Enlarge)
Mountain Dragon - Rankinia diemensis


Mountain Dragon - Rankinia diemensis


Mountain Dragons - Rankinia diemensis


Mountain Dragons - Rankinia diemensis


Mountain Dragons - Rankinia diemensis




Wednesday, 24 September 2008

Shield Spider / Badge Huntsman

.....Neosparassus diana (Koch, 1875)

This spider of the Sparassidae family is known as the Shield spider or Badge Hunstman. It hunts at night, usually on tree trunks and among foliage. By day it will be hidden away under some loose bark or even under stones. It has been known to occasionally come into houses. The one photographed below was certainly trying to come into my house as it was found on the back screen door. Fortunately it couldn't figure out how to pull the handle :-)

These spiders are fairly widespread in Tasmania and also occur on the mainland. The colour can range from yellowish brown to orange. The female's body length can be up to 22mm and the male 17mm. It has two straight rows of eyes with the eyes at the back being smaller. Between the two rows of eyes are some yellowish white hairs which to me gives the appearance of eye brows.

Another identifying feature is the 'badge' on the ventral surface of the abdomen. While this badge can vary a bit, it basically consists of a black area with two white spots. As I did not fancy holding the spider on it's back while taking it's photo, I have instead drawn a rough picture of the 'badge' which I have included below.

At this time of year (Sep/Oct) the female will make a nest by joining together some leaves or grass and within this she makes her egg-sac.


(Click on Photos to Enlarge)

Shield Spider - Neosparassus diana


Ventral view of abdomen showing the 'shield' or 'badge'


Tuesday, 23 September 2008

Gum-footed Tangle-web Spiders

.....family Theridiidae

The spider family Theridiidae gets it's common name from the structure of the webs. An apparent chaotic tangle, the web is in fact an ingenious trap consisting of vertically stretched threads that are attached to the ground with globs of gum. When the potential prey walks into one of the threads, it retracts and the prey is flung into more threads, thus immobilising it. . This family includes one of the most infamous of Australian spiders, the Redback, Latrodectus hasselti. However the spiders below belong to the closely related genus, Steatoda.

These tend to be smaller that the Redback but you will notice some similarity in form. Some even exhibit a small red spot. These are extremely common in my backyard and can be found under just about any rock (and believe me, as a vegetable gardener, when I tell you I have a lot of rocks here). I have even found them a good 600mm below the surface in a small cavity under a rock.

It is said a bite can induce headache and nausea but bites are not common due to the small size of the fangs.


(Click on Photos to Enlarge)

Steatoda.sp - This one found at least 600mm underground



Steatoda.sp - female with egg sac under a rock


Monday, 22 September 2008

More White's Skinks (Lizards)

A few weeks ago I posted about White's Skink. (Click for earlier post) Since then I have found another place in the backyard where they have made a series of burrows. This one was enjoying the sunshine on the path only about a foot away from one of the burrow entrances. Lying flat on the ground I was able to get close enough to use my 100mm macro lens. The first sudden movement I made and it it was back into the burrow in a flash.

The mention of sunshine should make it obvious that these shots were not taken today as I don't think the rain has stopped once. They were in fact taken last Tuesday (16th. Sep)

(Click on Photos to Enlarge)

#1 - White's Skink - Egernia whitii

#2 - White's Skink - Egernia whitii


Sunday, 21 September 2008

Some Birds From the Last Week

Here are a few birds from over the last week which do not warrant individual posts.

The Grey Fantails were at Rocky Cape National Park. They seemed to be all along the South Cave track with at least 6 being seen at once. They were often landing far too close to allow the camera to focus. The hardest part of photographing a fantail is anticpating where it will land next as they never seem to sit still for more than a second or so.

The Black-faced Cuckooshrike was at Table Cape. It's not a very good shot at all but it's the first I've seen this year and the first I've ever managed to photograph. Of course I was just about to get a terrific shot but some walkers came along and it flew off. (Nothing against the walkers - just bad timing)

The Little Pied Cormorant, the Tern, and the Heron were at Sulphur Creek which is where I was watching the Albatrosses yesterday.


(Click on Photos to Enlarge)

Grey Fantail - Rhipidura albiscapa


Grey Fantail - Rhipidura albiscapa


Black-faced Cuckooshrike - Coracina novaehollandiae



White-faced Heron - Egretta novaehollandiae



Little Pied Cormorant - Phalacrocorax melanoleucos


Little Pied Cormorant - Phalacrocorax melanoleucos


Crested (Swift) Tern - Sterna bergii


Saturday, 20 September 2008

A Spot of Sea Watching

With a good north-westerly blowing you can always be sure of a few Albatrosses coming in close to shore. As I've mentioned previously I've even spotted a few from my backyard when looking out to sea with the binoculars. Today was such a day with north-westerly and westerly winds gusting up to 80 kmph. I drove down the road to a little promontory where I could get a better view. There were lots of very heavy downpours with lashing wind and hail but nestled between a large rock and an old Hawthorn I was totally sheltered with an open view across a stormy sea. There were a few breaks in the rain too and even a few moments of sunshine allowing for some quick snaps.

At times there were up to 6 Albatrosses flying low among the waves. I found that it's easier to focus on them when then rise up higher so that they stand out against the sky.

Maybe someone can offer help with the identification. I have an opinion but cannot be sure. I would suggest the first one is a Shy Albatross and at the moment I'm leaning toward Black-browed Albatross for the second shot. Feel free to correct me.

Update: Four people have replied to my post on Birding-Aus and so far all agree with my ID.


(Click Photos to Enlarge)

Shy Albatross - Thalassarche cauta

Black-browed Albatross - Thalassarche melanophrys


Thursday, 18 September 2008

Austrocochlea constricta

.....a species complex

The many morphs of Austrocochlea constricta (family: Trochidae) have been a source of confusion among experts for many years so it's little wonder mere amateurs like myself can find them confusing.

These are common shells in the intertidal zone with vernacular names including Ribbed Top Shell and Zebra Top Shell. They are found on and under rocks where they feed on algae. When the tide is out the operculum is retracted quite deeply within the shell. As a result kids will often take them home thinking they are empty only to end up with a putrid mess.

The variation in these shells ranges from plain off white specimens through to dark heavily banded forms. This led to several morphs being given species status over the last two centuries. In the 1970's researchers concluded that the dark banding was primarily a result of environmental factors, it being proportional to the amount of chlorophyll in the food supply. Based on this and the apparent lack of biological differences, the various forms were considered to belong to just one species. Thus, most books of recent decades refer simply to A. constricta with many and varied forms. Others have maintained the name A. porcata for the heavily banded form.

However, according to research carried out in Tasmania (Parsons and Ward, 1994), there are not one, not two, but in fact 3 distinct species. These they say can be separated by genetic differences as well as morphological differences in both shell and animal. These differences hold true in populations where more than one form live side by side (sympatric) as well as where populations are isolated (allopatric). Thus while environmental factors may play some part in the variability of pigmentation within one species, it cannot explain the broad differences in morphology between the three species.

From the point of view of an amateur, the shell morphology is of most interest and provides an easy means of identification.

I have not seen A. porcata in my area so the first photo below is of specimens collected in the Sydney area in N.S.W back in the 70's. The next photo shows A. constricta from Sulphur Creek near Burnie. and third is A. brevis from Don Heads near Devonport.


In A. constricta the shell is a unicoloured off-white. It has pronounced spiral ribbing with 2 to 3 ribs on the penultimate (2nd last) whorl and 6 to 8 on the body whorl. Here on the north-west coast this is the dominant species.


(Click Photo to Enlarge)
Austrocochlea constricta

A. porcata has longitudinal stripes from the spire to the body whorl, alternating between off-white and black-to-red. The intensity of the pigmentation is uniforn right across the surface of the shell. The spiral ribbing is weak with 3 or 4 ribs on the penultimate whorl and 8 to 12 on the body whorl.


(Click Photo to Enlarge)
Austrocochlea porcata


In the new species A. brevis the spire is black to rubiginous. The body whorl is said to have flexuous, undulating, alternate bands of off-white and black-to-red, the pigmentation being most intense on the spiral ribs and faint or disrupted in between. It is weakly spirally ribbed (this can vary due to environment) with 2 to 4 ribs on the penultimate whorl and 3 to 11 ribs on the body whorl. Specimens from one location were unicoloured on the dorsal surface of the body whorl.


(Click Photo to Enlarge)
Austrocochlea brevis - (Top of spire worn)


.....Clear as Mud
It all sounds clear enough does it not? Well of course nothing is ever too simple. In their search through museum specimens they have found some intermediate forms which they suggest may be the result of either natural variation or possible hybridisation. Hmmmm.... well I guess that is to be expected but then this.... In 1996 further research was published on animals from the Abrolhos Islands and Albany in Western Australia. These Western Australian animals were genetically very similar to the Tasmanian A. constricta. However,when they looked at the morphological traits which were species-diagnostic in Tasmania, the Abrolhos animals most closely resembled A. porcata, while the Albany animals appeared intermediate to A. porcata and A. constricta.

Hmmm.... maybe I should take up basket weaving :-)


(A special thanks to Snail )

References:

  • Parsons, KE and Ward, RD (1994). Electrophoretic and morphological examination of Austrocochlea constricta (Gastropoda: Trochidae): A species complex. Australian Journal of Marine and Freshwater Research 45, 1065–1085.
  • Parsons, KE (1996). Discordant patterns of morphological and genetic divergence in the 'Austrocochlea constricta' (Gastropoda: Trochidae) species complex. Marine and Freshwater Research 47, 981–990. (Synopsis only)


Australian Jumping Spider

.....Breda jovialis

The Hunter Becomes the Hunted

After seeing JL's recent post here I mentioned that I would share this photo of an Australian Jumping Spider, Breda jovialis, taking a huntsman. It's not a recent photo - it was taken in October 2006.

In the bush these spiders are found under loose bark on trees but these days, the nooks and crannies of house walls and garden fences are equally acceptable to them. Adults are found during spring and summer. The females body length is 9mm while the males body length is only 6mm.

(Click Photo to Enlarge)

Australian Jumping Spider - Breda jovialis - takes a huntsman



Swamp Harrier

.....Circus approximans

Swamp Harrier's are migrants to Tasmania arriving in early spring. I saw my first for this year on the 19th August. Yesterday I noticed a pair near Table Cape which kept returning to the same spot on the ground. Perhaps they are preparing to nest as unlike many other birds of prey, the Swamp Harrier makes it nest on the ground, often among crops.

They will likely lay 4 to 5 eggs. Survival of the young will depend largely on the availability of food and any accidental run-ins with farm machinery. Their prey includes anything from insects to rabbits as well as carrion.

By around March next year almost all of our Swamp Harriers would have returned to the mainland with only a few choosing to spend the winter here in Tasmania. Robert Green records one bird that he banded at Antill Ponds in the Tasmanian Midlands. It was recovered the following winter at Goodwood Island at Chatsworth in northern New South Wales. According to Google Earth that's over 1,500 km's to the north (as the Harrier flies).

The photos below could be better but I'm happy in that they are the best I've managed for this species to date. Notice the loose feather on the head - perhaps the result of a dogfight with the local lapwings and ravens.


(Click Photos to Enlarge)

Swamp Harrier - Circus approximans


Swamp Harrier - Circus approximans


References:
  • Green. R. H. - 1995 - The Fauna of Tasmania - Birds , Potoroo Publishing, Launceston
  • Birds in Backyards - website