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DISPLAYING POSTS TAGGED: giant burrowing cockroach (1)

Bug of the month

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by Melvin
Publish date
1 October 2011
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This post is by Melvin Patinathan, Assistant Keeper with the Live Exhibits Unit.

The Giant Burrowing Cockroach (Macropanesthia rhinoceros), also known as the Rhinoceros Cockroach, is one of Australia's treasures. It is the world's heaviest cockroach, weighing up to a whopping 30g. Although it is not the longest, it still can get up to 70-80mm in length (the longest is probably the winged Giant Brazilian Cockroach, Blaberus giganteus, growing up to 90mm). This giant critter is wingless and heavily armoured, which helps it withstand predator attacks – if that doesn't work it can emit a hissing noise which can be quite startling.

Giant Burrowing Cockroach Giant Burrowing Cockroach (Macropanesthia rhinoceros).
Image: Alan Henderson
Source: Museum Victoria

I recently took the specimen below to Scienceworks for the Inspiring Scientists weekend, where he was a giant hit with hundreds of young visitors. Although I'm fond of many of the animals we keep at Live Exhibits, Giant Burrowing Cockroaches are one of my favourites.

Giant Burrowing Cockroach in hand The handsome hand shows how big a male Giant Burrowing Cockroach can get.
Image: Adam Elliot
Source: Museum Victoria
 

Giant Burrowing Cockroaches are found in dry eucalyptus scrubland of northern Queensland; Cape York to Rockhampton and the Whitsunday Islands. Male cockroaches have a prominent ridge on their pronotum (an extended first segment of the thorax of the insect that forms a shield over its head) where females do not have a distinct ridge but tend to be larger and heavier than males.

sub-adult Giant Burrowing Cockroaches A few sub-adults collecting dry eucalyptus leaves on the soil surface.
Image: Patrick Honan
Source: Museum Victoria
 

Like their name suggests, they are burrowing creatures and use their shovel-like pronotum and large spiny powerful digging legs to dig burrows as deep as one metre. The cockroaches line their burrows with twigs and dry eucalypt leaves that they gather from the surface. These gentle giants are specialist feeders; they only eat dry, crisp eucalypt leaves.

Giant Burrowing Cockroach emerging from its burrow in a terrarium Giant Burrowing Cockroach emerging from its burrow in a terrarium.
Image: Rodney Start
Source: Museum Victoria
 

Giant Burrowing Cockroaches are nocturnal and spend most of their time hidden in their burrows. They are most active at night when they come to the surface to feed; these giant cockroaches have been mistaken for small turtles when crossing roads.

Giant Burrowing Cockroaches generally do not venture too far away from their burrows except during breeding season when it is warm and humid, especially after rain. The warm humid climate provides ideal mating conditions and mating occurs at night. Once the female is gravid (pregnant) she will prepare her burrow by dragging down leaves to feed her young. This species of burrowing cockroach are oviviparous, which means that the eggs are incubated within the body and are sustained by yolk sacs.

young Giant Burrowing Cockroaches and adult female Juveniles and their mother at the entrance of their burrow.
Image: Patrick Honan
Source: Museum Victoria

Unusual among insects, instead of laying eggs, females of this species give birth to live young. The female giant burrowing cockroach will produce up to 20 live young and she will care for them for up to a year. Juvenile cockroaches reach maturity at about three or four years of age and best of all apart from being the heaviest cockroach in the world, these amazing cockroaches can live up to ten years.

Giant Burrowing Cockroaches are permanently on display under the 'Diversity' exhibit in Bugs Alive!.

Further reading:

Henderson A., Henderson D., & Sinclair J. 2008. Bugs Alive: A guide to keeping Australian invertebrates, Museum Victoria pp. 47

Rentz D.C.F. 1996. Grasshopper country: the abundant orthopteriod insects of Australia, University of New South Wales Press, pp. 225-228

Rugg D. & Rose H. A. 1991. Biology of Macropanesthia rhinoceros Saussure (Dictyoptera: Blaberidae). Annals of the Entomological Society of America, Entomological Society of America, pp. 575-582

Links:

Question of the Week: How to sex a cockroach

Question of the Week: Cockroaches

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Updates on what's happening at Melbourne Museum, the Immigration Museum, Scienceworks, the Royal Exhibition Building, and beyond.

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