Patrick

DISPLAYING POSTS BY: Patrick (14)

Patrick

Patrick Honan has sent spiders into space and helped bring the Lord Howe Island Stick Insect back from the brink of extinction. Now as Manager of Live Exhibits, he oversees all the living things on display at the museum, from tall trees to tiny ants.

Bug of the Month - Emperor Gum Moth

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by Patrick
Publish date
4 January 2013
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The apparent decline of the Emperor Gum Moth (EGM), Opodiphthera eucalypti, around Victoria has been a hot topic of debate amongst entomologists and other EGM fans in the last few years.

Emperor Gum Moth A newly-emerged male Emperor Gum Moth.
Image: Patrick Honan
Source: Patrick Honan
 

The decline is anecdotal and as yet there is no hard evidence, but theories abound. Many people contact us noting that they don’t see EGM caterpillars anymore, as they did when climbing trees as a kid. Which prompts a question in return: "When did you last climb a tree?"

Emperor Gum Moth Male Emperor Gum Moths have enormous feathery antennae used to detect the presence of females.
Image: Patrick Honan
Source: Museum Victoria
 

Another possibility is the demise of the introduced Peppercorn Tree (Schinus molle) in Victoria. Originally from the Peruvian Andes, Peppercorns were planted in every Victorian primary school and many parks from the 1880s to the early 1900s. EGM caterpillars, although feeding naturally on eucalypts, will also consume Silver Birch (Betula pendula) and Liquidambar (Liquidambar styraciflua), as well as Peppercorns. Victorians who went to primary school up until the 1970s would be very familiar with EGM caterpillars feeding on Peppercorns, but the trees have gradually died out or been removed until now there are very few left. Peppercorns are now considered an environmental weed.

Children planting trees State school children planting peppercorn trees in Carlton Gardens, just outside the now Melbourne Museum, on Arbor day, 1905.
Source: Reproduced from Carlton in DPCD report by Lovell Chen
 

Emperor Gum Moth The colour of adult Emperor Gum Moths varies considerably throughout their range.
Image: Patrick Honan
Source: Patrick Honan
 

Another strong possibility is the intrinsic variation in insect populations. Many species undergo booms and busts, appearing in vast numbers one year then apparently disappearing for several years afterwards, sometimes for a decade or more. These fluctuations are usually climate related, with each species requiring an exact combination of factors (such as a mild winter and a wet summer) in a particular order to afford them a boom year. Perhaps the last couple of decades have not produced the right combination for EGMs, and they’re just waiting for their number to come up.

European Wasp The dreaded European Wasp. Workers tear EGM caterpillars off trees and cut them into small pieces before transporting them back to the nest.
Image: Patrick Honan
Source: Patrick Honan
 

One of the most popular theories is attack by European Wasps (Vespula germanica) on EGM caterpillars. Caterpillars are a favoured prey of European Wasps, and they can do enormous damage when present in large numbers. However, somewhat ironically, after reaching plague proportions in the 1980s and 90s, wasp populations have dropped dramatically in the last 15 years or so, again for no discernible reason other than a possible combination of environmental factors.

Emperor Gum Moth caterpillar feeding An Emperor Gum Moth caterpillar feeding on Eucalyptus species.
Image: Patrick Honan
Source: Patrick Honan
 

In the end, any decline of EGMs probably comes down to habitat loss. The number of host gum trees has steadily reduced in urban areas in particular, but also in suburban areas and even rural towns. If fewer trees are available, there will naturally be fewer caterpillars. So if you’re missing these iconic caterpillars, the best strategy is to plant a gum tree.

Young caterpillars Young EGM caterpillars look very different to older caterpillars, but their presence is a possible sign of a healthy local environment.
Image: Patrick Honan
Source: Patrick Honan
 

But these theories are, at this stage, pure speculation. EGMs are still around, if you know where to look. A Museum Victoria Bioscan at Wilson’s Promontory in 2011 attracted hundreds of EGM adults (as well as the closely related Helena Gum Moth, Opodiphthera helena) to light traps at night. And just last month, a dozen EGM caterpillars were on display in the Forest Gallery at Melbourne Museum. Plans are underway to assess the extent of the EGM decline in Victoria, so stay tuned for further developments.

Further reading:

Coupar, P. & Coupar, M., 1992, Flying Colours – Common Caterpillars, Butterflies and Moths of South-Eastern Australia, NSW University Press, 119pp.

Common, I.F.B., 1990, Moths of Australia, Melbourne University Press, 535pp.

Zborowski, P. & Edwards, T., 2007, A Guide to Australian Moths, CSIRO Publishing, 214pp.

Bug of the Month - Giant Grasshopper

Author
by Patrick
Publish date
3 December 2012
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The Giant Grasshopper is so named for being the largest grasshopper in Australia. The adult's body length, however, varies from an enormous 90mm to less than half that size. This gives it the scientific name Valanga irregularis, referring not only to the irregular colouration but also the irregular length. People who know the species well simply call it Valanga.

grey grasshopper The mottled grey form of the Giant Grasshopper, common around Townsville, North Queensland.
Image: Patrick Honan
Source: Museum Victoria
 

Unlike many of the better-known grasshoppers, this species feeds not on grass but on the leaves of shrubs and trees. They have a very variable diet, ranging from native plants to citrus, cotton, coconut and even coffee plants. This makes them a minor pest in some areas, due to their occasional habit of consuming every leaf on a food plant when present in large numbers.

brown grasshpper The spectacular brown version of the Giant Grasshopper common around Iron Range, North Queensland.
Image: Patrick Honan
Source: Museum Victoria
 

Giant Grasshopper nymphs change colour with each moult, varying from light green to a spectacular red with blue stripes. The eggs are laid in batches of up to 150 within 'pods', made of a frothy substance that hardens upon drying. The eggs are sometimes attacked by a tiny parasitic wasp (Scelio flavicornis), which lays its own eggs inside the grasshopper's eggs, the wasp grubs feeding on the embryo within.

Brown and green forms of immature Giant Grasshopper Left: A young nymph. Right: An older bright green nymph.
Image: Patrick Honan
Source: Museum Victoria
 

Adult grasshoppers are very sensitive to movement and will leap away at the slightest disturbance. They can fly upwards as high as two metres, then horizontally in a straight line until they hit the ground. However, Giant Grasshoppers tire easily and the length decreases rapidly with each consecutive leap.

face of Giant Grasshopper A close encounter with a Giant Grasshopper from the Northern Territory.
Image: Patrick Honan
Source: Museum Victoria
 

Giant Grasshoppers occur across the top of Australia and there are a number of closely related species, at least four of which are undescribed. They are all very difficult to distinguish from each other, due to variations in most of the important characteristics, including size.

Giant Grasshopper eating A captive adult Giant Grasshopper satisfies its ravenous appetite with Orthopteran mix.
Image: Patrick Honan
Source: Museum Victoria
 

This species survives very well in captivity, feeding on a combination of fish flakes, grass seed, muesli, and pollen (known as Orthopteran mix). Unlike other insect species, they show no signs of inbreeding – a single mated female may be sole progenitor to tens of thousands of descendants over many generations without a single sign of genetic deformities.

exhibition display cases The Habitats exhibit, home of the Giant Grasshopper and many other spectacular creatures in Bugs Alive!
Source: Museum Victoria
 

Giant Grasshoppers can be seen in the Habitats exhibit in Bugs Alive! at Melbourne Museum.

Bug of the month - Steel Blue Sawfly

Author
by Patrick
Publish date
1 July 2012
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If you're out in the bush or a local park during winter, you're likely to happen across a group of 'spitfires' clinging to the branch of a gum tree in the cold. These insects are technically called sawflies, a group of insects closely related to wasps. There are more than 200 species of sawfly in Australia, but the local species is the Steel Blue Sawfly (Perga dorsalis).

sawfly larvae A small clutch of sawfly larvae clinging to a branch.
Image: Patrick Honan
Source: Museum Victoria
 

The name 'sawfly' derives from a 'sawbench' under the abdomen of the female with which she lays eggs. Female wasps, in contrast, use a pointed ovipositor to lay eggs and in some species this doubles as a sting – adult sawflies do not sting and both adults and larvae are completely harmless.

Patrick Honan Female Steel Blue Sawfly.
Image: Female Steel Blue Sawfly
Source: Museum Victoria
 

Female sawflies use the sawbench to cut the upper surface of a leaf and deposit 60-70 eggs into the leaf tissue. The larvae hatch and feed on gum leaves, grouping together for protection in a rosette pattern, similar to the head-outwards stance adopted by Bison when under attack. This is known as a 'ring defence', or cycloalexy. As the larvae grow, they collect in larger groups around branches during the day and spread out to feed at night.

sawfly eggs A raft of eggs cut into a gum leaf by a female Steel Blue Sawfly.
Image: Patrick Honan
Source: Museum Victoria
 

Like their cousins, the ants, bees and wasps, sawflies show some social behaviour but only in a primitive way. When feeding at night, larvae tap the branch to keep in constant communication with each other. If an individual becomes lost, it will tap more rapidly until it receives an answer from the rest of the group – if an individual becomes completely separated it will not survive long on its own.

Detail of sawfly larva abdomen. Sawflies grouped together on a branch. The pale tips of the abdomen are tapped on the branch to keep in touch.
Image: Patrick Honan
Source: Museum Victoria
 

The activities of a group of sawfly larvae are governed by a few select individuals that become in effect the leaders of the group. They lead the rest out to feed at night and, if they run out of food, lead the group across the ground to other trees. When large numbers of sawfly larvae are present they are able to defoliate small gum trees, but in general are not a major pest.

mass of sawfly larvae A mass of sawflies resting during the day, the result of the merging of several smaller groups.
Image: Patrick Honan
Source: Museum Victoria
 

When ready to pupate, the larvae leave the host tree and burrow down to make mass cocoons in the soil. Here they sit through spring and summer to emerge in early autumn. Adults have no mouthparts and do not feed, living only for a week or so.

pupating sawfly larvae Sawfly larvae in their pupal cells underground, preparing to pupate.
Image: Patrick Honan
Source: Museum Victoria
 

Not all emerge, however, as many succumb to parasitic flies. These flies, about the size of a blowfly, will lay eggs in the sawfly larvae and the fly maggot literally eats its host from the inside out, eventually emerging from the sawfly's cocoon.

parasitised sawfly larva An opened pupal cell showing the consumed sawfly larva on the left, and the engorged parasitic fly larva on the right.
Image: Patrick Honan
Source: Museum Victoria
 

Sawfly larvae have an unusual defensive mechanism that has given them the name 'spitfires'. They store eucalyptus oil in a small sac in their gut, and regurgitate this oil when under threat. Despite their nickname, they are unable to actually spit this fluid and the oil itself is harmless unless eaten (like all eucalyptus oil). In fact it has a very pleasant eucalytpusy smell.

sawfly larva mouthparts A large blob of frothy regurgitate in the mouthparts of a sawfly larva.
Image: Patrick Honan
Source: Museum Victoria
 

Australia is one of the main strongholds of Symphyta, the suborder of insects to which sawflies belong. The Steel Blue Sawfly is one of the few insect species active in Victoria during winter, so next time you're in the bush take the time to stop and smell the sawflies.

Faces of the north

Author
by Patrick
Publish date
9 March 2012
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Live Exhibits staff visited Cairns and Cape Tribulation in North Queensland in December to augment our live animal collection with fresh genetic stock. We met many interesting animals along the way, so here are a few portraits of the critters that came back with us to Melbourne Museum.

The Giant Mantid is one of the largest mantid species in Australia. They feed on a range of insects but are large enough to overpower small frogs and lizards. Giant Mantids are currently on display in Bugs Alive!.

giant mantid Giant Mantid, Heirodula majuscula.
Image: Patrick Honan
Source: Museum Victoria
 

Raspy crickets derive their common name from the fact that all known species, both male and female, can produce a rasping sound at all stages of development. There are more than 200 species of raspy crickets in Australia and new species are regularly discovered. This very large adult female has powerful jaws and, like all raspy crickets, a bad temper. She ate her way out of several containers on the journey from North Queensland, causing havoc wherever she went.

Raspy Cricket Raspy Cricket, Chauliogryllacris species.
Image: Patrick Honan
Source: Museum Victoria

A male Golden Huntsman, probably the largest huntsman in Australia and generally considered the second largest in the world. This species sometimes causes panic when it enters houses, but like most huntsmans it is relatively harmless.

Golden Huntsman spider Golden Huntsman, Beregama aurea.
Image: Patrick Honan
Source: Museum Victoria

Net-casting Spiders are famous for their ability to spin perfectly rectangular silken nets, about the size of a postage stamp. These nets are thrown over passing prey as the spider sits suspended above an insect pathway. In honour of their enormous eyes, they are also known as Ogre-Faced Spiders.

Net-casting Spider Net-casting Spider, Deinopis bicornis.
Image: Patrick Honan
Source: Museum Victoria
 

French's Longicorn is one of Australia's larger beetle species. This one was found in a small mating aggregation on a strangler fig in the rainforest at night. Longicorns are characterised by kidney-shaped eyes which wrap around the base of the antennae.

French's Longicorn beetle French's Longicorn, Batocera frenchi.
Image: Patrick Honan
Source: Museum Victoria
 

The spiny legs of the Serrated Bush Katydid give it both its common and scientific name. Adults are always green, but nymphs may be red, brown or violet, depending on the colour of the leaves on which they feed. Males produce a short, loud call which is commonly heard in the rainforest at night. Another katydid, the Kuranda Spotted Katydid, is one of the larger and more robust of this group in Australia. The nymphs closely resemble ants, which may afford them some protection against predators. The eggs are glued to dead twigs by the female using a short, thick ovipositor.

katydids Left: Serrated Bush Katydid, Paracaedicia serrata. | Right: Kuranda Spotted Katydid, Ephippitytha kuranda.
Image: Patrick Honan
Source: Museum Victoria
 

These creatures, and many more, can be seen every day in Bugs Alive! at Melbourne Museum.

Bug of the Month - Prickly Katydid

Author
by Patrick
Publish date
1 January 2012
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Prickly Katydids, or Spiny Tree Crickets, occur from the rainforests of northern New South Wales to Iron Range in Far North Queensland. There are four species of Prickly Katydids but the most common is Phricta spinosa. It has the rather long official common name of Giant Spiny Forest Katydid and is found from Innisfail to Cooktown. Those that know and love this species simply call it Phricta.

Prickly Katydid. The spiny countenance of a Prickly Katydid.
Image: Patrick Honan
Source: Patrick Honan
 

During the day, Phricta sits motionless on bark or amongst twigs with its legs held out straight where it is remarkably well camouflaged. Some bird species, particularly Black Butcherbirds, move up and down tree trunks trying to disturb the insects so they will give themselves away. When threatened, Phricta will point its back legs skyward, revealing rows of sharp spines and red patches at the bases of the legs. These red patches appear to discourage predators.

adult male prickly katydid The legs of this adult male bear the black and orange markings of its startle display.
Image: Patrick Honan
Source: Patrick Honan

Adults have a body length of 10cm or so, and their highly sensitive antennae may be three times that length. Adults are normally found high in the rainforest canopy, but after mating, the female glides to the ground to lay her eggs in the soil.

Prickly Katydid laying eggs An adult female pushes her abdomen into sandy soil to deposit a batch of eggs
Image: Patrick Honan
Source: Patrick Honan
 

The young Phricta feed low in the understorey on the constant 'rain' of flowers and buds from above.

A young nymph feeding on a fallen flower bud. A young nymph feeding on a fallen flower bud.
Image: Patrick Honan
Source: Patrick Honan

Phricta moult several times before reaching adulthood. Moulting takes place during the first part of the night and they are very vulnerable to predators at this time. The elongated antennae may take a long time to withdraw fully from the old skin.

Phricta moulting at night. Phricta moulting at night.
Image: Patrick Honan
Source: Patrick Honan
 

The colours of juvenile Phricta are variable and help camouflage them against tree trunks and lichen-covered bark.


Juvenile prickly katydid Juvenile Phricta are often beautifully patterned with greens and browns. The budding wing pads can be seen between the spines of the legs and thorax.
Image: Patrick Honan
Source: Patrick Honan

juvenile Phricta. A lichen-coloured specimen with a radically different colour pattern to other juvenile Phricta.
Image: Patrick Honan
Source: Patrick Honan

After reaching adulthood, Phricta can be found higher in the canopy, feeding on the young leaves of trees and shrubs. On particularly windy or stormy nights, they will move down into the lower canopy or into tree holes to shelter from the weather.

ovipositor of Phricta The long, sword-like ovipositor is visible at the end of this juvenile female's abdomen. Her oval-shaped 'ear' can also be seen just below the 'knee' of her right foreleg.
Image: Patrick Honan
Source: Patrick Honan

Like most katydid species, male Phricta call loudly to attract females in the rainforest at night, a sound familiar to people who frequent these forests. Females possess an auditory tympanum (or ear) on their forelegs to pick up the call.

Parasites on the thorax of juvenile Phricta. Parasites on the thorax of juvenile Phricta.
Image: Patrick Honan
Source: Patrick Honan
 

Phricta are attacked by owls and other predatory birds, as well as honeyeaters and brush turkeys. They are also host to parasitic mites, which gather sometimes in large numbers on the top of the thorax. The effects of these mites on the insects are not known.

Phricta can be seen in the 'Diversity' display in Bugs Alive! at Melbourne Museum. Despite being very common and widespread in North Queensland rainforests, this species was not described scientifically until 2005, an indication of how much is still to be discovered and catalogued by science.

Further reading:

Rentz, D., 1996, Grasshopper Country: the Abundant Orthopteroid Insects of Australia, University of New South Wales Press, Sydney, 284pp.

Rentz, D., 2010, A Guide to the Katydids of Australia, CSIRO Publishing, Collingwood, 214pp

Melbourne Museum’s high prune

Author
by Patrick
Publish date
18 August 2011
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Comments (1)

The Forest Gallery is one of the icons of Melbourne Museum – a cool temperate rainforest merging into drier eucalypt forest complete with creek, ponds and waterfall, all in the heart of a major city.

The gallery is dominated by large gum trees, wattles and southern beech, which have been growing consistently under the close supervision of Live Exhibits horticulturalists for more than 10 years. This is a ‘Forest in a Box’, a museum gallery in which the living trees must be strategically pruned on a regular basis in order to maintain the desired effect.

A view from above the fire poles. A view from above the fire poles at the northern end of the Forest Gallery, giving some idea of the height of the pruning operation.
Source: Museum Victoria
 

Last week arborists from ArborCo visited the Forest Gallery for an annual prune of the larger trees. The arborists must scale remarkable heights to reach the crowns of the trees, even before they commence their work.

Crew Leader Andrew Caldecott prepares to climb a Southern Beech for the annual trim. Crew Leader Andrew Caldecott prepares to climb a Southern Beech for the annual trim.
Source: Museum Victoria
 

Great attention is paid by the arborists to the health and safety of both themselves and the trees. Much of the preparation is done on the ground, and the pruning operation is planned weeks in advance. It must be done in such a way that preserves the natural shape of the tree and promotes growth in the right directions.

Arborist Joel Creech makes his way up a gum tree towards the upper canopy. Arborist Joel Creech makes his way up a gum tree towards the upper canopy.
Source: Museum Victoria
 

During their visit, the arborists also apply their skills to climbing one of the poles which houses the Forest Gallery’s wind gauge. The gauge is used to monitor wind speeds, and Museum staff will occasionally close the gallery temporarily if the wind becomes too strong.

Malachi Ewan at the top of a fire pole cleaning the wind gauge. Malachi Ewan at the top of a fire pole cleaning the wind gauge.
Source: Museum Victoria
 

Branches removed by the arborists are recycled on site into mulch, to be used on gardens throughout the Museum. When suitably aged, some of the mulch will be returned to the Forest Gallery to sustain the trees from which it came.

Mulching the prunings Left: ArborCo’s Gary Lambert feeds a steady stream of branches through the chipper. | Right: Brendan Fleming from the Live Exhibits Unit begins moving mulch back onto gardens around the museum.
Source: Museum Victoria
 

During the pruning operation, some of the branches cut from the Forest Gallery are tested to monitor the long term health of the trees. Foliage samples taken from new growth in the upper parts of the canopy can tell much about the trees’ nutrient content. Dr Peter Hopmans from Timberlands Research collects samples and uses them, in conjunction with soil samples and trunk diameters, in an ongoing review of plant health.

Collecting foliage samples Dr Peter Hopmans from Timberlands Research collecting foliage samples, watched by Brendan Fleming and Customer Service Officer Veronica Barnett.
Source: Museum Victoria
 

The Forest Gallery combines ancient geology and the power of water with living birds, reptiles, fish and frogs. It also exemplifies indigenous and European use and management of forests, and the role and impact of fire. But the heart of the forest is the giant trees that stand above all else, and ongoing management should ensure their existence for many years to come.

Links:

MV News: Forest gets a haircut

Pruning saves the Forest from the storm 

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