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Impurest's Guide to Animals #23 - Lord Howe Island Stick Insect

Hi guys I'm back from a full week of bat surveys (two more to go) so I apologise for any oddities with grammar and spellings that you may find in this issue. Last week the shy Saola was in the spotlight, not to mention where milk comes from. This week’s creature is just as rare, having even come back from the dead. Hope you enjoy

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Issue #23 - Lord Howe Island Stick Insect

[1]
[1]

Kingdom – Animalia

Phylum – Arthtopoda

Class – Insecta

Order – Phasmetodea

Family – Phasmatidae

Genus – Drycocelus

Species – australis

Related Species - The Lord Howe Island Stick Insect is a member of the Eurycanthinae subfamily also colloquially known as Land Lobsters (1)

Range

The Lord Howe's Island Stick Insect is only found on Ball's Pyramid (foreground) although it was traditionally found on Lord Howe's Island as well (background) [2]
The Lord Howe's Island Stick Insect is only found on Ball's Pyramid (foreground) although it was traditionally found on Lord Howe's Island as well (background) [2]

The Lazarus Stick

The Lord Howe Island Stick Insect is a large arboreal insect that can grow up to fifteen centimetres long (with females being large then the males) and almost twenty five grams in weight. Unlike the majority of Stick Insects, D australis is flightless but compensates this by having more muscular legs then its relatives, enabling them to run rather than simply wobble forward like other Phasmids (Stick and Leaf Insects).

[3]
[3]

Like all Phasmids, the Lord Howe Island Stick Insect is an herbivore and specialised browser, only feeding on the leaves of Melaleuca howena, a hardy myrtle plant that grows only on Ball’s Pyramid, and formally on Lord Howe’s Island. Before the arrival of humans from mainland Australia, the Lord Howe Island Stick Insect had no natural predators, but the introduction of rats (Rattus rattus) to the island whipped out the entire population within two years of their arrival (3). Declared extinct in 1960 the insect wasn't seen again, save for a few dead specimens washed out on the tide, until 2001, where scientists discovered a population of 24 individuals (making the species a Lazarus Taxon) living on a 4x30 patch of vegetation on Ball’s Pyramid.

[4]
[4]

TThroughbreeding schemes, not easy since Lord Howe’s Island Stick Insects form pair bonds for life, the wild population is now around 350 animals, with a large reserve population in captivity ready for reintroduction to Lord Howe’s Island. The Australia government is currently look at plans to reclaim the insect’s ancestral home, despite the cost and lengthy time period required to exterminate the rodent invaders and plant subsequent food stocks to support a valid population (3).

Conservation Crisis: Five to Save #1 - Insects

Insects are not the first animal group that springs to mind when conservationists mention endangered species, yet a significant number are at risk of extinction. In addition it has been theorized that a large number of undiscovered species could be extinct before we have a chance to discover them. Of the ranks of endangered hexapods, the following five are some of the most at risk individuals (1);

American Burying Beetle (Nicrophorus americanus) - Critically Endangered

Threats - Habitat Destruction: Fragmentation over their Eastern Range has caused populations to fragment into non-viable long term populations. In addition to inbreeding the limited resources has led to the species to be out competed by more efficient insect scavengers.

Hajar Wadi Damsel Fly (Arabineura khalidi) - Endangered

Threats - Habitat Destruction: Living in only a few desert pools in Oman and the United Arab Emirates the Hajar Wadi Damsel has to compete for water with irrigation schemes and recreational use. Being restricted by a sea of sand, once its breeding pools are destroyed the entire population could become extinct within a single generation.

Middle Island Tusked Weta (Motuweta isolata) - Endangered

Threats - Invasive Species: Despite being a formidable predator in its own right the Middle Island Weta, like Lord Howe’s Stick Insect, is under threat from introduced rodents and possums, species which it has no natural defence from. In addition a large bush fire on Middle Island, while making a dent in the rat population, has severely reduced Weta numbers as well.

St Helena Earwig (Labidura herculeana) - Critically Endangered (Potentially Extinct in the Wild)

Threats - Invasive Species: While rodents are indeed responsible for the demise of the St Helena Earwig, it’s through the decimation of sea bird populations that the rats caused the most damage. Remains suggest that the earwig favoured areas near seabird nests, possibly scavenging on leftovers and dead chicks, before the birds left the island due to predation. The species hasn’t been seen in the wild for at least forty years.

Wallace’s Golden Birdwing Butterfly (Ornithoptera Croesus) - Endangered

Threats: Accidental Killing: Large scale insecticide sprays (to combat mosquitoes) on the forest homes of the Golden Birdwing has resulted in large numbers of casualties, not only of butterflies, but other insects as well. No doubt the large scale logging operations scheduled to move into the forest, would also contribute to the endangerment of the species as well.

Bibliography

1 - www.arkive.org

2 - http://www.npr.org/blogs/krulwich/2012/02/24/147367644/six-legged-giant-finds-secret-hideaway-hides-for-80-years?sc=fb&cc=fp

3 - http://www.smh.com.au/articles/2003/10/18/1066364522158.html

Picture References

1 - http://www.arkive.org/media/E7/E75170CC-6B33-4E6C-90B5-EF2031E97033/Presentation.Medium/Lord-Howe-Island-stick-insect.jpg

2 - http://lordhowe.com/files/2012/10/Balls-Pyramid.jpg

3 - http://m3.i.pbase.com/g4/29/842929/2/140083873.oj309Tda.jpg

4 - http://news.bbc.co.uk/nol/shared/spl/hi/sci_nat/02/lord_howe_stick_insect/img/stick_carlile_pop.jpg

Thanks for reading guys; I hope you enjoyed the Lord Howe’s Stick Insect and it’s tenacious battle for survival. Make sure to drop me a comment and suggest an animal to be covered in future issues, and as usual you can check out past issues in Impurest’s Bestiary.

Many Thanks

Impurest Cheese

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