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DISPLAYING POSTS TAGGED: entomology (15)

Wanderer or Monarch butterfly

Author
by Patrick
Publish date
8 March 2013
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Comments (7)

The Wanderer Butterfly is known overseas as the Monarch Butterfly, so named for being the King, or Queen, of butterflies. In North America they are also known as King Billies, after William of Orange. The Australian name of Wanderer comes from its remarkable habit of long distance migration. The scientific name Danaus plexippus was bestowed by Carolus Linnaeus, the father of taxonomy and inventor of the scientific naming system.

Adult female Wanderer Butterfly Adult female Wanderer Butterfly
Source: Patrick Honan
 

Although not a native to Australia, the Wanderer may not exactly be introduced in the usual sense. Wanderer Butterflies most likely arrived in Australia across the Coral Sea from Vanuatu or New Caledonia, carried by three cyclones in early 1870. This was part of a major expansion in distribution across the Pacific and Atlantic Oceans from North America in the late 1800s, probably due to a combination of environmental factors, human movement and natural expansion.

Wanderer butterfly feeding An adult Wanderer Butterfly feeding on Cat's Whiskers (Orthopsiphon aristatus).
Source: Patrick Honan
 

The first recorded observations from Australia were made in February 1871 in Queensland, followed by the first record from Melbourne in April 1872. It is possible that Wanderers had been making the journey to Australia since time immemorial, but only after Europeans established their food plants here could Wanderers establish.

Wanderer caterpillar The distinctive fleshy 'filaments' behind the head of the caterpillar are used as sensory organs.
Source: Patrick Honan
 

Wanderers have been seen at sea up to 500km from land and occasionally settle on passing ships. This is not unusual – with favourable winds, Australian butterflies such as Common Eggflies often end up in New Zealand. Wanderers have a cruising speed of about 30km per hour with bursts of up to 50km per hour when alarmed.

Wanderer Butterfly pupa. The wings of the adult can be seen through the walls of a Wanderer Butterfly pupa.
Source: Patrick Honan
 

In North America, Wanderers undertake a famous annual migration from Canada and northern USA down to Mexico and California, and then back again. The populations overwintering in the Oyamel Fir Forests of Mexico roost at densities of 10 million butterflies per hectare. Because the length of time required for the migration exceeds that of an adult Wanderer's life span, those arriving back in Canada are the descendents of those that left the year before.

Map of butterfly migration Map of the North American migration of the Monarch or Wanderer butterfly that occurs each year in autumn.
Source: Via the Frost Lab, Queen's University Department of Psychology
 

The secrets of the Wanderer migration in North America weren't fully revealed until the 1970s. Canadian Dr Fred Urquhart was fascinated as a child by the question of where all the Wanderers disappeared to during winter, and he and his team of volunteers took nearly 40 years to discover the answer. Professor Urquhart died in 2002 but his life-long search is the subject of the new film Flight of the Butterflies 3D. In Australia, Dr Courtenay Smithers from the Australian Museum began tagging Wanderer Butterflies in the 1970s using many volunteers from the broader community. His studies revealed that overwintering populations around Sydney and Adelaide move into Melbourne and surrounds during summer. This research continues, with many questions still to be answered. In certain years, for example, populations appear to overwinter in some parts of Victoria, such as Phillip Island and the Western Districts, without needing to move interstate, but more data is needed to confirm these observations.

Flight of the Butterflies 3D opens at IMAX Melbourne Museum on 21 March. 

Patrick's next post on these butterflies: More on the Monarch

References:

Clake, A.R. & Zalucki, M.P., 2004. Monarchs in Australia: On the Winds of A Storm? Biological Invasions, 6:123-127

McCubbin, C., 1970, Australian Butterflies, Thomas Nelson Ltd, Melbourne, 206pp.

Bug of the month - Steel Blue Sawfly

Author
by Patrick
Publish date
1 July 2012
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Comments (14)

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.

Plague Soldier Beetles

Author
by Jo
Publish date
15 January 2012
Comments
Comments (148)

Your Question: What are these swarming beetles in my garden?

The Discovery Centre has received many enquiries over the last few weeks about swarms of beetles in suburban gardens in and around Melbourne; they are Plague Soldier Beetles, Chauliognathus lugubris.

Plague Soldier Beetles Plague Soldier Beetles
Image: Peter Saunders
Source: Peter Saunders
 

 

This flattened, elongated, soft-bodied beetle has a thin yellow-orange stripe across the back of the pronotum. It has metallic olive green elytra (hardened forewings), covering most of a yellow-orange abdomen. The legs, head, antennae and rest of the pronotum are black and the beetle is usually about 15mm in length. This native species has earned its common name of the Plague Soldier Beetle not as a result of bringing or spreading any dangerous plagues, rather due to its habit of forming huge mating swarms.

 

Plague Soldier Beetles Plague Soldier Beetles
Image: Peter Saunders
Source: Peter Saunders
 

 

The larvae of this species live in the soil and feed on soft bodied invertebrates, while the adults feed on pollen and nectar. The species is found across large parts of the country including urban areas and adults can be seen from spring through to autumn. During their mating periods they can appear in such large numbers that it is not uncommon for them to weigh down the limbs of weaker plants.

Their bright colour warns off predators as they are capable of releasing distasteful chemicals and would not make a good meal. For homeowners who may be hosting huge numbers of this colourful species, don't be too concerned, following the mating swarm the beetles tend to disperse.

 

Got a question? Ask us!

A moth flurry on the Murray

Author
by Mark Norman
Publish date
15 December 2011
Comments
Comments (1)

Mark is Head of Sciences at Museum Victoria. He's reporting back from Neds Corner in this series of blog posts.

There was a flurry of excitement among our moth team over the diversity of moths and some exciting new records for the region and state. Members of the Entomological Society of Victoria, Marilyn and Dean Hewish, Grace Lewis, Ken Harris and Josh Grub, set up night light stations with bright mercury vapour lamps in front a large white sheet. They run all night, as different groups of moths arrive at different times of the night. They clocked up over 120 moth species.

Two Neds Corner moths Left:Sceliodes cordalis | Right: A perfectly camouflagued Convolvulus Hawk Moth, Agrius convolvuli.
Image: M. Hewish
Source: M. Hewish
 

There are several theories on why moths come to human light sources. The generally accepted theory is that moths use points of light in the night sky (such as the moon) to orient their flight paths. They keep the brightest light at a particular angle to their flight direction in order to fly straight. As they go past our electric lights they keep turning inwards to maintain the correct angle until they spiral into the porch light or the light station sheets.

The arriving moths came in all shapes and sizes. Two of the weirdest were the Twisted Moth and the plume moths. The Twisted Moth contorts its body as part of its camouflage to look very not-moth-like. The plume moths have long narrow wings with the rear pair hidden under the front pair. They get their name from the feathery tips to their wings.

Two Neds Corner moths Above: Twisted Moth, Circopetes obtusata looks just like a dry eucalyptus leaf. | Below: A plume moth, Stenoptilia zophodactylus
Image: M. Hewish
Source: M. Hewish
 

Colour patterns ranged from the excellent camouflage of the hawk moths that perfectly match the grey tree bark to brightly coloured forms including some with false eye spots, known as ocelli.

Two brightly-coloured Neds Corner moths Two brightly-coloured Neds Corner moths. Left: Pale Spotted Tiger Moth, Amata aperta | Right: Grammodes ocellata with beautiful eye-spots, or ocelli.
Image: M. Hewish | D. Hewish
Source: M. Hewish | D. Hewish
 

The wood moths (family Cossidae) caused the most excitement. These beautiful moths are not particularly common and the three species found included two ornately-patterned species and a third smaller species that is a new record for Victoria. The males of these moths (and many other moth groups) can be recognised by their large feather-like antennae. These are the chemosensory organs of the males, used to 'smell' the pheromones released by the females. By contrast, females have much narrower, less-feathery antennae.

two wood moths Two wood moths. Left: Endoxyla sp. | Right: Endoxyla neuroxantha representing a new Victorian record for this species.
Image: M.Hewish
Source: M. Hewish
 

Bush Blitz is a biodiversity partnership discovery program between the Australian Government, BHP Billiton and Earthwatch Australia, that aims to document the plants and animals across Australia's National Reserve System. Museum Victoria also participated in Bush Blitz at Lake Condah in March 2011.

Cute creepy crawlies

Author
by Mark Norman
Publish date
3 December 2011
Comments
Comments (3)

Mark is Head of Sciences at Museum Victoria. He's reporting back from Neds Corner in this series of blog posts.

The range of invertebrate animals that we found at Neds Corner was spectacular. At the robust end of the scale were the Rasping Crickets with their big jaws and impressive biting powers. We encountered pairs of these large crickets, the females having the long egg-laying ovipositor off the tip of their tail.

Rasping Cricket Rasping Cricket
Image: David Paul
Source: Museum Victoria
 

We also found the delicate pottery brood chambers built by potter wasps. They build these perfect small chambers to contain their young and then bring food to the developing grubs.

Potter wasp adult and nest Above: Adult potter wasp | Below: The nest of the potter wasp.
Image: Patrick Honan | Mark Norman
Source: Museum Victoria
 

Grace Lewis from the Entomological Society of Victoria witnessed the life and death tug-of-war between a spider wasp and meat ants over a paralysed wolf spider. The ants won.

Antlion larva and adult Above: Antlion larva in its conical pit | Below: Winged antlion adult
Image: David Paul | Mark Norman
Source: Museum Victoria
 

The ants were not so lucky in the many antlion pits we found scattered in the red sand. Antlions are the juvenile stage of an insect related to the lacewings (order Neuroptera). The young antlions with their big jaws dig a conical pit in the sand and sit in the bottom waiting for ants to slide in. The flying adults were attracted to our night lights. We also saw another related insect known as a mantis fly or mantispid – it has a lacewing body with the attacking front end of a praying mantis.

Mantispid Mantispid or mantis fly
Image: Mark Norman
Source: Museum Victoria
 

The centipedes were beautiful and fast, with lots of legs for running. We also found small red-eyed cicadas everywhere and saw them emerge from their wingless cases.

Colourful centipede Colourful centipede
Image: Mark Norman
Source: Museum Victoria
 

Dr John Stanisic of the Queensland Museum was pleased with his tally of ten land snail species including some of the smallest animals imaginable. Our photographer David Paul has perfected photographing "gliding sand grains".

Tiny land snail Tiny land snail
Image: Mark Norman
Source: Museum Victoria
 

Every day we found more radical colours, shapes and sizes amongst the invertebrate fauna than the day before.

Bush Blitz is a biodiversity partnership discovery program between the Australian Government, BHP Billiton and Earthwatch Australia, that aims to document the plants and animals across Australia's National Reserve System. Museum Victoria also participated in Bush Blitz at Lake Condah in March 2011.

Links:

Parks Australia blog

Bush Blitz

Winning photo

Author
by Kate C
Publish date
18 July 2011
Comments
Comments (4)

A photograph by museum entomologist Dr Ken Walker has just won a coveted place in the annual international Leica calendar. In 2012, the company’s calendar will feature microscope photographs, and Leica put out a call for entries. Ken’s photograph of the head of a tiny, undescribed lichen moth in the genus Chamaita (family Arctiidae) was one of 12 selected.

male lichen moth The winning photograph of the head of a male lichen moth.
Image: Ken Walker
Source: Museum Victoria
 

The photograph, as well as being incredibly beautiful, is an important diagnostic tool.  This species is a pest in palm plantations in New West Britain, Papua New Guinea. To assist those who need to identify it, the species has its own page , featuring the winning photograph and others, on PaDIL (Pests and Diseases Image Library).

Says Ken, "It’s a great recognition for the photographic skills we have developed here over the past six years to have an image to be used in the high-quality calendar." The competition was open to anyone using Leica microscope and camera equipment; the prize is a Leica EZ4 dissecting microscope. This prize will go right back into PaDIL’s suite of specialist technical equipment to create more photographs like this one.

Links:

PaDIL

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