The Hunters and the Hunted
Transverse Ladybird (Coccinella transversalis), adult and larva, & aphids
Spring and early summer are the time of garden shows in the valley. For those with the taste for European gardens, roses seem to be the showy flower of choice. But whilst visitors walk around admiring the blooms, right under their noses, on the millimetre scale, nature’s life and death struggles continue unabated.
Most gardeners, particularly of roses, will acknowledge aphids as one of their main garden pests. Aphids are soft bodied sap-sucking insects. Many species are plant specific in that they only feed on one type of plant. They congregate on plants in large numbers. When a particular stem or flower becomes overcrowded new aphids are born with wings so that they can move to another food source.
Lacewing
What can stop these ravenous hordes? There are a number of insects (and their larvae) that feed on aphids. A surreptitious peek at the underneath of the blooms during the garden shows revealed not just aphids in abundance but also their predators grazing on them. Ladybirds, ladybird larvae, lacewings and parasitic wasps were all there – nature’s balance being maintained.
Parasitic Wasp
In fact there were so many aphids and things feeding on them I am sure if people walked around the gardens listening, the visual feast of the flowers would have been accompanied by the audio soundtrack of quiet sucking and munching.
A Tawny tale
Arriving at the chook shed to fix a hole where a fox had got in and wreaked havoc with our hens, we discovered that someone had left a feather duster outside the shed – or so it seemed. It turned out to be a fluffy Tawny Frogmouth chick who presumably had fallen out, or prematurely tried to fly out, of a giant Yellow Box tree that overhangs the shed.
With the young bird looking very vulnerable and a fox known to be around, the question was: to intervene or not? Unable to locate a nest or any adult birds in the tree, we felt there was the possibility that the chick had been abandoned, but there was also a chance the parents were keeping an eye on it – and us! In the end we lifted the ball of fluff, without protest, from the ground onto the low roof of the shed, hopefully out of reach of any fox.
After dusk we discovered the chick gone, but a couple of frogmouth silhouettes swooping low around us and emitting a soft ‘woop-woop-woop’ (rather than their usual resonant ‘oom-oom-oom’ call) indicated that it had not been abandoned. Next morning the chick was back in the same spot on the ground outside the shed gate. So repairs were again put on hold.
A more careful scan of the tree finally revealed the rudimentary nest with one adult bird and what could have been another fluffy juvenile beside it. Further out on a limb was another adult showing its beautifully patterned plumage. A couple of hours later the presence of a second wide-eyed chick was confirmed as it had shifted position to be beside the second adult – see photo at left.
On nightfall our little friend showed it could at least get off the ground as it flapped up onto fence wire then the top of a couple of gates. Somewhat reassured we left it to its own devices.
After a wild windy night none of the frogmouth family were visible the following morning – not surprising as the nest was on the exposed windward side of the tree. But the fate of the brood is unknown. It’s a tough world out there and we can only hope for the best. But at least the repairs to the chook shed can proceed in time for the arrival of a new lot of hens today.
Click on any of the photos below to view as a slide show.
Third time lucky
Back in September we ran a post about a pair of Eastern Spinebills nesting in a bushy bay tree close to our house. That event ended badly when we discovered the two still unfeathered chicks gone and the nest abandoned. The parents were not having much luck as that was the second nest in the same tree. We suspected the culprit in both failed attempts was a Grey Currawong which had been hanging around the garden.
Being persistent, but perhaps not very smart, the pair of spinebills soon started building a third nest in the opposite side of the same tree. To our surprise their persistence paid off and two fledglings eventually left the nest. A couple of days later one was spotted in a melaleuca, lacking the coloration of its parents and trying to pretend it was invisible – see photo above.
Here today, gone tomorrow
The wet winter and warm spring have meant that insects which have an aquatic nymph stage have had a great season – think mosquitoes. Another such insect is the Mayfly (pictured left). Living most of its lifecycle (years) as a nymph the lifetime of an adult mayfly is brief – measured in hours. This stage of the lifecycle is so small the insect has no need to eat and therefore the adult has no mouthparts. When the conditions are right (i.e. now), mayfly nymphs leave the water en masse, emerge from their sub-imago state and in the time they have left, mate and then die.
The nymphs live in clean water environments and feed on underwater vegetation and detritus. Over the period of months/years they progress through several moulting events before they emerge from the water after the final moult as a sub-imago. The sub-imago (pictured right) is sexually immature and does not have the colouration of the sexually mature adults. After a couple of days the adult mayfly ‘hatches’. The pictures below show various stages of the adult emerging.
Mayflies are of the same order as Damselflies and Dragonflies and look similar. However there are some characteristics by which you can tell the difference. They have two pairs of wings but one pair is much smaller than the other. At rest the wings are folded over the back like most damselflies. Male mayflies have very long front legs. These are used to grasp the female in flight so that airborne mating can occur (Fly United indeed). Extending from the back of the insect are three filaments. The outer two are called cerci. A lot of insects have cerci. In mayflies they are sensory organs. In insects such as earwigs they form defensive pincers.
It is the head of the mayfly that is most distinctive. Like their related cousins, the dragonfly and damselfly, mayflies have a pair of compound eyes and three ocelli (a set of simple eyes thought to detect light and dark and therefore help an insect fly level). In addition the adult mayfly has two huge ‘turban eyes’ mounted on the top of the head. These eyes detect ultraviolet light and are thought to assist in the detection of females flying overhead.
At this time of the year adult mayflies can be found in their thousands resting on aquatic vegetation and flying above the water looking for mates.
Live fast, die young – the mayfly motto.
Rock’n’roll lives
The view from my bedroom window is down the valley to the Tallarook Range. The King Parrot Creek (the water body around which this blogsite is based) flows generally north to the Tallarook Range and then skirts north-eastwards along its base to join the Goulburn River at Kerrisdale. Recently I had the opportunity to go to the AGM of the Dabyminga Landcare Group, situated on the other side of the Tallarooks from our Strath Creek Landcare Group.
After the meeting Eamon, the son of the president (now ex-president), took me to see his scorpion collection. Producing an ultraviolet light source (commonly known as black-light) the fish tank in which the creatures were kept was suddenly populated by brightly glowing animals. Pictured below is one of Eamon’s Black Rock Scorpions (Urodacus manicatus) seen under ultraviolet light.
Scorpions fluoresce a bright cyan colour under ultraviolet light. The exact reason for this is unknown. It has been suggested that the shell is a giant sensory organ so that the animal can find shelter in the low light conditions in which it lives. Other explanations include that the fluorescence either attracts prey, warns predators or enables scorpions to recognise each other.
Either way, the phenomenon is well known to the lads on the other side of the range who, equipped with UV lights, go out at night ‘rock-rolling’ to locate and collect the scorpions as pets. Even though I have never encountered a scorpion on the rocky slopes where I live further up the valley from the Tallarooks, I think I’ll give it a try.
I’m a rock’n’roller from way back.
Beetle control
Despite its magical properties in folk lore and its current popularity as a medicinal plant, St. John’s Wort (Hypericum perforatum) can be an invasive environmental weed and a serious noxious weed in grazing paddocks. The reason for the latter is that it contains a substance called hypericin which can induce a strong photosensitive reaction in livestock, sometimes leading to a severe loss in condition and even death. It is a declared Regionally Controlled Weed in most of Victoria which means landholders must take all reasonable steps to control it and prevent its spread.
The common means of control is by chemical spraying, but there are some little beetles that can provide an alternative biological control. These are active in small numbers on our roadside at present – see photos. They are Chrysolina beetles which in sufficient numbers can cause heavy defoliation of St. John’s Wort plants, suppressing flowering and seed set. Individual beetles have a metallic sheen varying in colour from green to bronze or blue.
These beetles have an interesting story to tell. Two species, Lesser St. John’s Wort Beetle (Chrysolina hyperici) and Greater St. John’s Wort Beetle (Chrysolina quadrigemina) were introduced from Europe into Australia in the 1930s as biological agents for the control of this weed. (Australian-bred beetles were subsequently introduced to New Zealand and North America.)
Both the larvae and the adults feed on St. John’s Wort leaves, and consequently ingest significant amounts of hypericin, enough to make them photosensitive. But they have adapted their feeding habits to counter this accumulation of toxin. Young larvae feed at night and hide in leaf-buds in the daytime, while older larvae spend the day burrowed in the soil. Adults avoid flying from plant to plant during the day, as their elytra (wing covers) when closed protect them from light, so the toxic hypericin cannot become activated. They will move about in daylight, exposing the cuticle, only when threatened with starvation, although they sometimes drop to the ground and play dead when disturbed.
So, if you find clusters of shiny beetles on your St. John’s Wort, hold off on the spraying and let these little fellows do the control work for you!
[Incidentally, one sure way of identifying young non-flowering St. John’s Wort from superficially similar native Pimelea species which also grow on our roadsides is the presence of numerous translucent hypericin-containing oil glands on the leaves of St. John’s Wort – these can be seen in the photo at left – click for a closer look.]
It’s the citizens that count
Science is expensive – research, clinical trials, collecting data. The trend in recent times has been to involve the general public. Across the country there are thousands of people only too happy to help, particularly with data collection.
The Aussie Backyard Bird Count is one of those activities. Participants are asked to sit for 20 minutes and record the bird species they observe. It is run every year for a week in October. This year there were over 1.4 million bird records submitted. The cost of privately funding that type of data collection would be prohibitive.
Not only is sitting still for 20 minutes a nice contemplative practice but in that time the birds seem to either not realise or they forget that you are there. This can afford an opportunity to observe them in greater detail, particularly those birds which are particularly flighty and take off as soon as you appear. In my garden one such bird is the New Holland Honeyeater (Phylidonyris novaehollandiae). Looking like a cross between a Collingwood and a Richmond supporter (in colour that is), the New Hollands are very active birds and are easily spooked. As their name suggests these honeyeaters feed on nectar and spend their time flitting between flowering bushes.
Another citizen science project coming up next week is the Spring Wild Pollinator Count held between 13 & 20 November 2016. With a similar format to the Bird Count, people are asked to observe a flower for 10 minutes and record what pollinators come to visit it.
When one thinks of pollination the Honey Bee immediately comes to mind but you would be amazed at the variety of fauna that fulfil this function – many species of insects, birds and even animals.
This week I have been ‘warming-up’ to the task. Pictured are a couple of pollinators around at the moment.
So next week spend 10 minutes watching a flower. It might surprise you what turns up.
Where’s the Rexona?
An interaction with a bright green beetle recently left me doubting my personal hygiene.
The critter in question was a Green Carabid Beetle (Calosoma schayeri), pictured above. Regarded as a beneficial insect this beetle has long legs for fast movement and is a voracious predator of caterpillars. The head of the beetle is equipped with an impressive array of mandibles and palps to help it sense and eat its prey (pictured below) and the wing-cases are ridged. The larvae are also predacious feeding on the eggs, larvae and pupa of other insects. The adults live under bark on trees and the larvae live underground.
This beetle is a member of the larger family of beetles known as Carabidae or Ground Beetles. One of the features of this family is that members have glands on the abdomen which produce noxious fumes. In some species (not this one) the fumes can be injurious if not deadly to mammals and invertebrate animals looking to eat it for lunch.
Naturally I picked up the beetle to have a good look at it and it ‘bombed’ me. Only later when researching this blog did I realise my Rexona was working.
Nice to look at but…
A one-bird band
The Olive-backed Oriole pictured left is a bird familiar to many in our district over the warmer months, mostly recognised initially by its distinctive, repetitive “Orry-orry-ole” call. What is probably less well-known is that the oriole is quite an accomplished mimic. Not in the same class as lyrebirds to be sure, but on occasions snatches of mimicry are included with its regular call, along with other harsh notes and warbles. (We once searched for a Golden Whistler near Mt. Black in the Heathcote-Graytown National Park that appeared to be singing in a group of low trees, only to discover the culprit was an Olive-backed Oriole!)
We have been hoping for a long time to record this mimicry (see a 2013 post, A distinctive call) and had the chance the other day with an oriole calling in roadside trees near Strath Creek. For about half an hour it warbled away with a mix of its regular call and a sub-song that included mimicry. Unfortunately there was a strong wind blowing (when hasn’t a strong wind been blowing lately!) – not good for sound recording!
But in the audio files below we think, with a little imagination, we can hear snippets of the calls of Rufous Whistler, Yellow-tailed Black Cockatoo, Common Blackbird, Sacred Kingfisher (the lovely trill) and perhaps others we haven’t identified. The only other bird close by was a Yellow-faced Honeyeater, whose call can be clearly heard, but the oriole seemed to be trying to mimic that too.
Then again, perhaps this is all just wishful thinking!?
nga’chuq rites
Fans of Star Trek, particularly those who can read or understand the Klingon language will know that nga’chuq rites are the mating rituals of the Klingon species. These rituals are physically demanding resulting in blood being shed and often bones being broken. In fact the breaking of a collar-bone on the wedding night is an extremely auspicious sign for the wedded union.
A cry of ‘snake in the garden’ from my ‘urban’ sister resulted in several people running to observe, instead of a snake, two Eastern Blue-tongue Lizards (Tiliqua scincoides) mating. Blue-tongue Lizards are the largest members of the Skink family. Eastern (otherwise known as Common or Northern) Blue-tongues are distinguished from their closely related cousins, the Southern Blue-tongues, in that they have striped rather than blotched markings. Eastern Blue-tongues mate between September and November and give birth to three to five live offspring between December and April.
In the garden the male lizard had grasped the female firmly on the back with its teeth as the latter tried to escape (see picture above top). After several minutes of gyrations the female escaped with a gaping back wound. Last seen the female lizard was heading into the bush being hotly pursued by its mate (with genitalia clearly on display), pictured above.
Although no bones were broken the incident looked very Klingon-esque.
Focus On Fauna 