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DISPLAYING POSTS TAGGED: bugs alive! (4)

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.

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 - Rainforest Mantid

Author
by Caitlin
Publish date
1 March 2012
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One of the largest insect species we keep here at Melbourne Museum is the Rainforest Mantid (Hierodula majuscula). At around 70mm in length, the adult Rainforest Mantid is not the longest mantid species in Australia, but it is certainly the most buff.

An adult female Rainforest Mantid on the hunt for prey An adult female Rainforest Mantid on the hunt for prey
Image: Alan Henderson
Source: Minibeast Wildlife
 

Its powerful raptorial forelegs are equipped with razor-sharp spines that allow the mantid to pin and immobilise live prey. A resident of north Queensland rainforests, the adult's solid green colour enables it to all but disappear amongst the foliage. A mantid on the hunt may remain perfectly still for hours, waiting for the right prey to present itself. Looming over its meal and appearing to "pray", the mantid finally strikes with lightning-fast accuracy and shows its true colours as another of nature's perfect predators.

The life of the Rainforest Mantid begins as one of up to 400 hatchlings from the ootheca – an egg case laid by the female 40-60 days prior. Often attached to the underside of a branch or leaf, the hatchlings emerge downwards and crawl over one another to clear the way. The nymphs must disperse from their brothers and sisters, as once they start eating, any prey small enough is fair game - including each other! At this stage, H. majuscula nymphs are less than 10mm long. As the nymph moults and grows, it may vary from greens to browns and reds, but is invariably green by its final moult.

Mantid nymphs hatching and moulting Mantid nymphs hatching and moulting for the first time after emerging from the ootheca.
Image: Alan Henderson
Source: Minibeast Wildlife
 

A superb hunter, the Rainforest Mantid's best weapon is its vision. Its large, compound eyes boast a wide field of vision, enhanced by its head's extraordinary range of movement. As a result, the Rainforest Mantid hunts primarily during daylight hours.

 

Mantid with large eyes Large eyes dominate the Rainforest Mantid's triangular, highly mobile head.
Image: Alan Henderson
Source: Minibeast Wildlife
 

An adult mantid is able to prey on not only a large selection of insects, but may also attack small lizards and frogs. After securing the prey with its raptorial forelegs, the mantid devours it alive. These mantids often eat the nuisance parts first, such as an insect's powerful kicking legs.

 

Mantid eating a cockroach Insect prey is usually consumed head-first to reduce the chances of it getting away.
Image: Alan Henderson
Source: Minibeast Wildlife
 

The Rainforest Mantid lives a solitary life and may never come into contact with another of its species after hatching until it is time to breed. Only the mature male of this species is capable of flight, so it is left to him to navigate the precarious expanse of tropical rainforest to find the perfect a female who is ready to mate. In contrast to hunting, night seems to be the preferred time for mating (though it may begin during or continue into daylight hours). As a flying male is quite vulnerable, it is thought that breeding takes place in the dark to reduce the risk of aerial predators.

However, there is still one major group of insect predators active at this time – the microbats. To combat this, many mantid species including H. majuscula have evolved a single ear on the lower side of the thorax, capable of picking up the ultrasonic sound frequencies of the microbats' echolocation signals. If the male mantid in flight detects such a signal, he immediately dives and weaves in such a display of evasive manoeuvres that he has been compared to a fighter jet.

In the dark, mantid eyes are much less effective. To counter this, a female of the breeding inclination sends out pheromones to attract suitable males. Once the male locates a female, he tempers his approach until the correct moment. He may wait hours within thirty centimetres of her, before rushing her in a mad frenzy and attaching himself to her back with his forelegs. If he is lucky, he will have attached himself a way that prevents her turning around to eat him. If he is unlucky, he may immediately become a meal. Either way, the Rainforest Mantid male can continue to mate even with his head completely missing. It's not all bad news for the male's genes: by becoming an extra meal, he may give his offspring a greater chance of survival by nourishing the female through the month of egg incubation.

Mantids mating This male is one of the unlucky individuals that has not survived the mating process.
Image: Alan Henderson
Source: Minibeast Wildlife
 

Rainforest Mantid females may live for up to a year. Though males may be capable of living just as long, their risky lifestyle results in a lower average life span. However, if a male survives mating, he may go on to mate with many more females and live to a ripe old age.

Bug of the month

Author
by David P
Publish date
1 September 2011
Comments
Comments (1)

Prior to becoming a keeper with the Live Exhibits team at Melbourne Museum, my knowledge of grasshoppers was quite limited. Locusts were probably the type of grasshopper of which I was most aware, due to their high numbers during the warmer months. They are also responsible for the must-have car fashion accessory adorning the front of vehicles, in the form of flywire to stop cars from overheating. In truth, locusts are just one of an estimated 700 species of grasshopper in Australia.

Common Toad Hopper The Common Toad Hopper (Buforania crassa) is an inquisitive creature.
Image: David Paddock
Source: Museum Victoria
 

Live Exhibits keeps many different types of grasshoppers and I am quite intrigued by them all, but the species which first caught my attention was the Common Toadhopper (Buforania crassa) from Central Australia. They are not particularly big - females are approximately 60mm long and males 40 mm long - and contrary to their name they rarely hop or jump, preferring to walk around. They have been described as an inquisitive grasshopper and that is what drew me to them. As with pets at home, if you are looking after an animal and you buy it a new toy or feed it a new food then you hope that they will enjoy it or get a reaction from it. I found that not too long after I added food they would be on it or in it. This included pollen, orthopteran mix (made up of muesli, fish flakes and other ingredients), and various forms of foliage, such as abelia, emu bush, acacia, and callistemon. You soon find out that they have their favourites - I would say that callistemon is in the top two.

Common Toad Hopper eating callistemon Common Toad Hopper (Buforania crassa) eating callistemon, one of its favourite foods.
Image: David Paddock
Source: Museum Victoria
 

Like most grasshoppers, Common Toadhoppers use camouflage to hide from predators. As you can see from the picture, once they are perched on a rock or stick during the daylight hours they can be very difficult to see. If they are brought up on a light sand substrate then their colours will reflect that.

Common Toadhopper camouflage Common Toadhoppers are masters of camouflage. Their colours can vary depending on what colour substrate they are brought up on.
Image: Patrick Honan
Source: Museum Victoria
 

Camouflaged Toadhopper Toadhopper perfectly disguised to match the branch it's sitting on.
Image: Alan Henderson
Source: Museum Victoria
 

Their reproductive cycle is very interesting. Grasshoppers generally breed in the summer months with the male perching on the female's back, either mating or guarding her from other males. The female then deposits her eggs in the soft sand and plugs them with a foamy substance. Our toadhopper populations here at Melbourne Museum vary seasonally and in some enclosures we currently have none at all, but we can see where females have deposited their eggs. Grasshopper eggs are good at withstanding drought periods. Normal incubation time for Common Toadhoppers is 1-3 months but it can be as long as 1-2 years, the eggs simply waiting for the right conditions. We can recreate those conditions, simulating warmer days with longer heat and light periods, and heavy rain through flooding the enclosures with water. Then hopefully not too long afterwards, little toadhopper nymphs will appear and even though they may not live up to the second part of their name, these grasshoppers certainly love eating grass.

young Common Toadhopper. A young Common Toadhopper.
Image: Alan Henderson
Source: Museum Victoria
 

In the meantime, come along to Melbourne Museum and visit our male Common Toadhopper, featured in the arid section of our Habitats display in Bugs Alive!.

arid habitat display Toadhoppers are in the arid habitat display in Bugs Alive!.
Image: David Paddock
Source: Museum Victoria
 

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