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Next time, just a tickle

March 11, 2021

One thing I have noticed on my property is that Black Wattles (Acacia mearnsii) germinate as a group i.e. the seedlings all spring up at the same time. This obviously is a result of the conditions being right but it doesn’t happen every year. So I have clumps of wattles of different heights all growing and subsequently dying together.

Recently a grove has ‘taken off’ next to the dam. All the saplings had a dense head of foliage apart from one. It was denuded of leaves. Closer examination of the tree revealed half a dozen large caterpillars (pictured below) contentedly grazing on the foliage. My interest in caterpillars is directly proportional to how big they are. I therefore have found in the past Emperor Gum Moth (Opodiphthera eucalypti) caterpillars fascinating and these new examples were no exception.

The visitors were Golden Notodontid Moth caterpillars (Neola semiaurata). One would have that thought with all the decorations this caterpillar would have been easy to identify but for me it wasn’t. There are MANY species of moths. So I had to resort to a Facebook moth identification page (the wonders of social media!).

As I tend to have a non-disturbance policy when photographing fauna what I didn’t realise is that when disturbed the caterpillar rears its head back and a bright red protuberance (called an osmeterium) erupts from its throat. In addition, normally hidden under flaps of skin near the tail are bright blue eye-spots which the caterpillar displays when bothered. Sounds very photogenic.

I’m watching out for this caterpillar next year. I might give it a little tickle.

Small bird, big excitement

March 1, 2021

The Weebill (Smicrornis brevirostris), pictured left, is Australia’s smallest bird. The scientific name unsurprisingly comes from the Greek mikros meaning small and the Latin words brevis meaning short and rostrum meaning bill.

Weebills are found throughout mainland Australia, most commonly found in areas with dry, open eucalypt forests. They feed on insects primarily scale insects, psyllids and their lerp constructions. As such Weebills are usually found in the upper story of trees where the fresh new leaves and hence the sap-sucking insects are found. Around our district they are easily located in noisy mixed flocks, locally known as the ‘tribes’ as they scour the landscape for food.

The nest (pictured above) is pendant shaped with a hole in the side. It is constructed of grass and bark bound together with silk from spider webs and animal cocoons and animal hair. Nests are usually constructed in the canopy of trees. This one was found on an easily photographed flimsy branch just off the ground….

causing big excitement about the littlest of birds.

Hidden jewels

February 23, 2021
Castiarina sp.

Jewel Beetles are highly coloured and probably the most collectable of the insects, after tropical butterflies. The colour in each case is not an inherent feature of the insect but results from the diffraction of light from the insect surface (a similar process to how rainbows are formed). In butterflies the diffracting surfaces are the scales on the wings. For Jewel Beetles and other highly coloured beetles, pictured left, the colour is due to light being diffracted by small ridges on the exoskeleton.

Whilst weeding the lawn I came across a Jewel Beetle-ish looking beetle coloured black and white, pictured right. Upon closer examination it did the typical Jewel Beetle behaviour when threatened of retracting the antennae and legs and dropping to the ground revealing jewel-like colours underneath (pictured below). It is a Callitris Jewel Beetle (Diadoxus erythrurus). (Callitris is a genus of coniferous tree native to Australia and New Caledonia).

The adult Jewel Beetle lives for a relatively short time (days to weeks). Most of the lifecycle is spent in the larval stage. The larvae in this case bore into Callitris trees favouring dying or dead branches on otherwise-healthy trees.

A wise insect the Callitris Jewel Beetle keeps its treasures well hidden.

Not all dams are created equal

February 13, 2021

One would think that in any given area one dam would be much the same as another in terms of the existing biota. I am not sure it’s that simple.

In my neighbour’s dam at about this time of the year dusk signals the time for dragonfly nymphs to leave the water by climbing up the reeds and emerge as adult dragonflies. It is quite a remarkable spectacle. But in my dam, nothing. The only things ascending are myriad of mosquito bites on my arm as I sit fruitlessly watching for anything to emerge. Recently I travelled ‘over the hill’ to investigate someone else’s farm dam. To my surprise the reeds were populated by a type of spider I had never seen before, Long-jawed Spiders (Tetragnatha sp.), lots of them, pictured below.

Long-jawed spiders are elongated orb-weavers building small orb webs in vegetation bordering waterways. Their jaws are often more than half the size of their bodies. They eat arthropods trapped in their webs or capture by stalking them and are excellent at walking on the surface of water travelling faster on that surface than on land.

That’s all you need. A spider with extra large jaws that can walk quickly on land and water.

You wouldn’t put money on it

January 20, 2021

For experienced birdwatchers the metric by which to assess success is the number of species seen in a calendar year. If you have lived in a given area for any length of time this usually means counting the species that you have already seen in previous years. You wouldn’t put money on observing a ‘lifer’, a species you had never seen before.

I am not an experienced birdwatcher so there are still occasions when I see a lifer. Yesterday I heard a bird call (my time with the Murrindindi birders is paying off!) I had never heard before. Perched high in a eucalypt was a bird I had never seen – dark head with a deep blue sheen on its body. It was a Dollarbird (Eurystomus orientalis). The scientific name comes from the Greek eurustomos meaning wide mouth and orientalis meaning eastern.

Dollarbirds are members of the roller family so called because of their acrobatic courting and territorial aerial displays. The Dollarbird is the only roller found in Australia, its distribution stretching along the entire east coast and up into SE Asia, Korea and Japan. It comes to Australia in Spring and Summer to breed and then winters in New Guinea. Our area seems to be the limit of its southern migration. Juvenile birds have brown beaks and feet that turn bright orange on maturity. This species feeds on insects taken in flight and nests in tree hollows.

The term Dollarbird comes from the pale light-blue coin-shaped colouration that can be seen on their underwings when in flight.

That makes cents.

Slip, slidin’ away

November 6, 2020
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A neighbour of mine has a regular night-time routine – slug hunting. Rain, hail or shine she is out with a torch hoping to rid her garden of these pests. Slugs and their shelled cousins snails make up a class of animals known as Gastropods, creatures which have the same general characteristics, like:

  • Snails and slugs have two tentacles extending from the front of the head, pictured left. The upper two are the eye stalks. The lower pair contains ‘smell’ organs and is retractable.
  • These animals are hermaphroditic, having both male and female sex organs (I wonder how they decide which one to use!)
  • The snail shell keeps growing during the life of the snail. Calcium carbonate is added to the shell from the base that gets larger with time to accommodate the growing body. The shell spirals in a clockwise direction.
  • Snails and slugs have a single lung-like organ. The breathing hole known as the pneumostome is on the right side of the body and opens and closes as the animal breathes (pictured above). In snails the pneumostome is hard to see as the shell often obscures the view.
  • Snails and slugs have a series of microscopic teeth known as a radula with which they scrape lichen and other vegetative matter off surfaces.

Finally snails (not sure about slugs!) are delicious sautéed with parsley butter and garlic with a squeeze of lemon, and a glass of cold Chablis (I am not sure that applies to our garden snails).

It depends how you look at it

October 23, 2020

One group of the plants flowering at the moment, if you are looking carefully are Australian bush orchids. They come in a vast array of shapes, sizes and colours. Most orchids replicate by producing seed and for this to happen they need to be pollinated. Some species self-pollinate but the majority rely on insects to do this task. Most orchids however do not produce nectar or pollen with which to attract the insects but instead use various deceptions to lure them. These generally take two forms, food deception and sexual deception.

Orchids that use food deception look like plants that provide insects with pollen or nectar. The Common Donkey Orchid (Diuris orientis), pictured above, mimics the bush-pea flowers of the Fabaceae family, for example Common Bossiaea (Bossiaea prostrata), pictured right. The orchid flowers are larger than the pea flowers thus creating a more visible target for nectar-seeking insects.

Orchids that use sexual deception have petals that look like female insects. The flowers emit a pheromone that attracts the male insect who then proceeds to ‘pseudo-copulate’ with the orchid petal. The Orchid Dupe Wasp (Lissopimpla excelsa), pictured below, is so named because it is one of the insects deceived.

This wasp, a native of Australia, ‘mates’ with plants of the genus Cryptostylis, the Tongue Orchids. To the human eye the orchid petals are similar in colour to a female wasp. However to the visual system of a wasp, more in the green, blue and ultraviolet range, the similarity is more striking.

It depends how you look at it.

The perils of being a Crane Fly

October 5, 2020

A walk through the long grass at the moment should disturb clouds of Crane Flies (pictured left). Unlike dragonflies, damselflies and scorpion flies, Crane Flies are true flies i.e. they are two-winged Dipterans. These slow flying long-legged insects are short-lived, up to a couple of weeks, so short-lived that some species do not even possess mouthparts for eating and drinking and the female fly emerges from the pupa stage already containing eggs for the next generation. Despite their short lifespan, many Crane Flies do not even reached that potential as their lives filled with dangers.

For a start their long legs mean that Crane Flies are often mistaken for mosquitos and being a slow flyer many cranefly/human interactions often do not end well (for the Crane Fly). But nature also throws up a number of other hazards. Crane flies are the prey of fish, birds, mammals and other insects. Spiders are also natural predators, not only those that build webs but also Jumping Spiders (pictured below) that have the ability to leap out and ambush the unwary.

It is not just the local fauna that can end the life of a Crane Fly prematurely. Local flora in the form of Tall Sundews (Drosera peltata) can also lead to a sticky end if you are a Crane Fly. The long dangling legs are prone to get snagged on the tentacles of this carnivorous plant (see below).

I’ve heard of the saying ‘Live fast, die young’. For Crane Flies ‘Live slow, die younger than the short life span you already have’ seems apt.

Things come to those who wait

September 30, 2020

When cycling through the district I keep an eye on any water body I pass in the hope of seeing an elusive rakali or platypus. Ripples on the water surface could indicate the presence of either. And so whilst riding I saw some tell-tale ripples. The trick then is to be still and wait to see what caused them.

Whilst waiting, two Spotted Pardalotes (Pardalotus punctatus) slowly made their way down a nearby tree, branch by branch, chirping loudly as they went. These are exquisitely coloured birds (pictured left) not often seen because they feed on lerp, the honeydew/wax houses that the nymphs of psyllid insects construct to live in. Psyllid nymphs are generally found on young eucalypt leaves i.e. at the top of a tree hence this is where pardalotes hang out.

The two birds I was watching dropped to the ground and scurried to the nearby road bank and started digging into the side of the bank (pictured right). Spotted Pardalotes nest in horizontal oval chambers usually connected to the outside world by a tunnel up to 1.5 metres long. The nests are usually built in riverbanks and embankments but have been found excavated in piles of builders sand on housing sites. The nest is lined with shredded bark. A neighbour of mine built a successful nest box from agricultural poly-pipe leading to a wooden box.

After half an hour of industrious work the pair flew off…and the water ripples were caused by ducks. Watch this space for further developments.

There’s a crayfish in the garden

September 18, 2020

Last week I was asked whether slaters were harmful to the garden. So I looked back at all the blog posts we had written over the past decade and discovered we had never discussed these ubiquitous critters – apart from one blog post on Slater-eating Spiders.

Slaters are crustaceans just like lobsters and prawns and are an introduced species in Australia. Although terrestrial they still have a need to be in a moist environment, commonly living under rocks, logs and leaf litter and coming out at night when the chances of dehydration are minimised. They have seven pairs of legs and two pairs of antennae. The female slater does not lay her eggs but carries them around in a pouch. The young remain in the pouch for a short time after hatching. They look like small adults and grow through a series of moulting stages. Unlike most arthropods the moult takes place in two stages rather than one. The exoskeleton splits and the back half is shed, followed by the front half a couple of days later.

And as to the garden question, slaters are great in the garden. They are detritus feeders, feeding on decayed plant (and animal) matter and returning nutrients to the soil.

I am glad evolution chose these to come on to land. Can you imagine having crayfish in your garden hiding under your flower pots?