Home | Insects | Ant Mimicry in the Giant Spiny Stick Insect (Macleay’s Spectre), Extatosoma tiaratum: An Unbelievable Survival Strategy

Ant Mimicry in the Giant Spiny Stick Insect (Macleay’s Spectre), Extatosoma tiaratum: An Unbelievable Survival Strategy

 

Today I’ll introduce a member of a group of insects that have long fascinated me – the stick insects, or walking sticks. Several of the over 2,700 described species are well established in captivity, especially among European hobbyists. They are growing in popularity here in the USA also, most commonly, I’ve noticed, among reptile and amphibian keepers. (Note: laws governing the keeping of insects vary from country to country and state to state; please check those applicable to you before purchasing insect pets). Giant Spiny Walking Stick

Ants as Babysitters

Today’s insect hails from Australia and New Guinea (as do most truly bizarre creatures!). I’ll cover the husbandry of the giant spiny stick insect in the future…for now I’d like to provide you with a look at its most incredible reproductive strategy.

Female giant spiny stick insects lay approximately 12 eggs at a time, and may produce up to 1,000 or more during their lives. They fall to the ground after being quite forcibly ejected by the cloaca.

The eggs resemble seeds and are tipped with a structure known as a capitulum. The captiulum’s collar is a favored food of ants of the genus Leptomyrmex. The ants carry the eggs into their nest, where the collar is eaten. The stick insect’s eggs are then discarded in the ant colony’s underground rubbish pile, where, protected from predators and the fires that regularly ravage the forests above, they develop.

Tricking the Ants

The walking stick nymphs mimic Leptomyrmex ants in color (black body, red head) and move about in a rapid, frantic manner as do the ants (adult stick insects are slow moving). They also curl their abdomens up over the body, in the manner of their ant hosts.

Upon leaving the ant nest the stick insects moult, assume the adult body form and coloration, and climb into trees to live. All walking sticks undergo incomplete, or hemimetabolous, metamorphosis – there is no pupae stage.

A Variable Path to Reproduction

This species may reproduce either sexually or by parthenogenesis. Eggs produced via mating hatch in approximately 4 months, while those produced via parthenogenesis may take 9 months or more to hatch.

Strange, even for an insect, don’t you think? I’m always interested to hear about unique survival strategies…please write in with your own favorites and I’ll share them in future articles.

You can read more about this and related stick insects at:

http://www.novelguide.com/a/discover/grze_03/grze_03_00194.html#Macleays_spectre

Image referenced from Wikipedia and originally posted by Stephan M. Hohne

http://en.wikipedia.org/wiki/Image:Extatosoma_tiaratum_114.jpg

2 comments

  1. avatar

    My understanding of these guys is that they are illegal in the US without a permit from the USDA, and thus out of reach of private hobbyists. Any chance that will change? A lot of them are still being passed around “underground” here, I understand they used to be quite popular, as they still are in Europe and some other places.

  2. avatar

    Hello, Joseph, Frank Indiviglio here. Thanks for your comment.

    As of now, the USDA requires permits for all non-native insects and for all herbivorous non-insect invertebrates, i.e. Australian stick insects, Asian mantids and African millipedes are covered, Vietnamese centipedes are not. Technically, even the hissing roaches that are in so many classrooms throughout the country are included in the permit requirements (in fact, just this week Florida Fish and Game began an investigation into the various species of roaches being sold instate). All sorts of insects are sold openly without permits, and have been for decades, so how all will play out is anyone’s guess…actually, now that I think of it, even the common pet trade house cricket and super mealworms are not native…

    I’ve been through the permitting process as few times, and it is quite tedious. Permits have been granted to private individuals…usually long-established importers with a significant collection. In the past, exceptions had been granted for those seeking to keep male invertebrates only, but I’m not sure if this still being done.

    Best regards, Frank Indiviglio.

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Being born with a deep interest in animals might seem unfortunate for a native Bronxite , but my family encouraged my interest and the menagerie that sprung from it. Jobs with pet stores and importers had me caring for a fantastic assortment of reptiles and amphibians. After a detour as a lawyer, I was hired as a Bronx Zoo animal keeper and was soon caring for gharials, goliath frogs, king cobras and everything in-between. Research has taken me in pursuit of anacondas, Orinoco crocodiles and other animals in locales ranging from Venezuela’s llanos to Tortuguero’s beaches. Now, after 20+ years with the Bronx Zoo, I am a consultant for several zoos and museums. I have spent time in Japan, and often exchange ideas with zoologists there. I have written books on salamanders, geckos and other “herps”, discussed reptile-keeping on television and presented papers at conferences. A Master’s Degree in biology has led to teaching opportunities. My work puts me in contact with thousands of hobbyists keeping an array of pets. Without fail, I have learned much from them and hope, dear readers, that you will be generous in sharing your thoughts on this blog and web site. For a complete biography of my experience click here.

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