Dryococelus australis, commonly known as the Lord Howe Island stick insect or tree lobster,[2] is a species of stick insect that lives on the Lord Howe Island Group. It is the only member of the monotypic genusDryococelus. Thought to be extinct by 1920, it was rediscovered in 2001.[3] It is extirpated in its largest former habitat, Lord Howe Island, and has been called "the rarest insect in the world", as the rediscovered population consisted of 24 individuals living on the small islet of Ball's Pyramid.
Adult Lord Howe Island stick insects can measure up to 20 centimetres (8in) in length and weigh 25 grams (1oz), with males 25% smaller than females. They are oblong in shape and have sturdy legs. Males have thicker thighs than females. Unlike most phasmida, the insects have no wings.
The behaviour of this stick insect is highly unusual for an insect species, in that the males and females form a bond in some pairs.[4] The females lay eggs while hanging from branches. Hatching can happen up to nine months later. The nymphs are first bright green and active during the day, but as they mature, they turn black and become nocturnal.
Reproduction can happen without the presence of males (parthenogenesis) and this quality has allowed the species to survive when they are low in numbers.[5]
History and conservation
The stick insects were once very common on Lord Howe Island, where they were used as bait in fishing. They were believed to have become extinct soon after the supply ship SSMakambo ran aground on the island in 1918, allowing black rats to become established. After 1920, no stick insects could be found.[3][6] However, in 1964, a team of climbers visiting Ball's Pyramid, a rocky sea stack23 kilometres (14mi) south-east of Lord Howe Island, discovered a dead Lord Howe Island stick insect. During subsequent years, climbers found a few more fresh carcasses, but expeditions to find live specimens were unsuccessful.[6]
In 2001, Australian scientists David Priddel and Nicholas Carlile hypothesised that there was sufficient vegetation on the islet to support a population of the insects, and, with two assistants, travelled there to investigate further. They scaled 120 metres of grassy, low-angled slope, but found only crickets. On their descent, the team discovered large insect droppings under a single Melaleuca shrub growing in a crevice approximately 100 metres above the shoreline. They deduced that they would need to return after dark, when the insects are active, to have the best chance of finding living specimens. Carlile returned with local ranger Dean Hiscox and, with a camera and flashlights, scrambled back up the slopes. They discovered a small population of 24 insects living beneath the Melaleuca shrub amongst a substantial build-up of plant debris.[3][6]
In 2003, a research team from New South Wales National Parks and Wildlife Service returned to Ball's Pyramid and collected two breeding pairs, one destined for a private breeder in Sydney and the other sent to the Melbourne Zoo. After initial difficulties, the insects were successfully bred in captivity in Melbourne.[6] The ultimate goal was to produce a large population for reintroduction to Lord Howe Island, providing that a project to eradicate the invasive rats was successful. In 2006, the captive population of insects numbered about 50 individuals, with thousands of eggs still to hatch. In 2008, when Jane Goodall visited the zoo, the population had grown to 11,376 eggs and 700 individuals,[6] 20 of which were soon after returned to a special habitat on Lord Howe Island.[7]As of April2012[update], the Melbourne Zoo had reportedly bred over 9,000 of the insects,[8] including 1,000 adult insects, plus 20,000 eggs.
In 2012, the Budapest Zoo was the first zoo in the world to reproduce it.[9]
In 2014, an unauthorised climbing team sighted live stick insects near the summit of Ball's Pyramid, in a thicket of sedge plants rooted in very thin soils at an altitude of 500 metres, suggesting that the insect's range on the island is more widespread than previously thought, and that its food preferences are not limited to Melaleuca howeana.[10]
By the beginning of 2016, Melbourne Zoo had hatched 13,000 eggs, and had also sent eggs to the Bristol Zoo in England, the San Diego Zoo in the United States, and the Toronto Zoo in Canada, to establish distinct insurance populations.[11]
A 2017 study comparing DNA sequences of phasmids originating from Ball's Pyramid with those from museum specimens from Lord Howe Island showed that the Ball's Pyramid sequences differ from those of Lord Howe Island by a degree comparable to variation within the museum specimens, despite some morphological differences between the two groups.[12] This confirms that the two populations represent the same species. The genome was found to be very large in size (over 4 Gb) and is probably hexaploid.[13]
In 2018 it was announced that the CEO of the Lord Howe Island Board had approved a plan to exterminate the black rat population on Lord Howe Island to protect the island ecology and potentially reintroduce D.australis.[14]As of 2023[update] plans are being made to reintroduce the insects to Blackburn Island, a smaller island offshore of Lord Howe Island, to test the potential for reintroduction to the larger island.[15]
The Phasmatodea are an order of insects whose members are variously known as stick insects, stick-bugs, walkingsticks, stick animals, or bug sticks. They are also occasionally referred to as Devil's darning needles, although this name is shared by both dragonflies and crane flies. They can be generally referred to as phasmatodeans, phasmids, or ghost insects, with phasmids in the family Phylliidae called leaf insects, leaf-bugs, walking leaves, or bug leaves. The group's name is derived from the Ancient Greek φάσμα phasma, meaning an apparition or phantom, referring to their resemblance to vegetation while in fact being animals. Their natural camouflage makes them difficult for predators to detect; still, many species have one of several secondary lines of defense in the form of startle displays, spines or toxic secretions. Stick insects from the genera Phryganistria, Ctenomorpha, and Phobaeticus include the world's longest insects.
Lord Howe Island is an irregularly crescent-shaped volcanic remnant in the Tasman Sea between Australia and New Zealand, part of the Australian state of New South Wales. It lies 600 km (320 nmi) directly east of mainland Port Macquarie, 780 km (420 nmi) northeast of Sydney, and about 900 km (490 nmi) southwest of Norfolk Island. It is about 10 km (6.2 mi) long and between 0.3 and 2.0 km wide with an area of 14.55 km2, though just 3.98 km2 of that comprise the low-lying developed part of the island.
Ball's Pyramid is an uninhabited islet in the Pacific Ocean located 20 kilometres (12 mi) southeast of Lord Howe Island. The steep rocky basalt outcrop is the eroded plug of a shield volcano and caldera that formed 6.4million years ago. It is 572 metres (1,877 ft) high, while measuring 1,100 metres (3,609 ft) in length and only 300 metres (984 ft) across, making it the tallest volcanic stack in the world.
A rare species is a group of organisms that are very uncommon, scarce, or infrequently encountered. This designation may be applied to either a plant or animal taxon, and is distinct from the term endangered or threatened. Designation of a rare species may be made by an official body, such as a national government, state, or province. The term more commonly appears without reference to specific criteria. The International Union for Conservation of Nature does not normally make such designations, but may use the term in scientific discussion.
Land lobster may mean:
The Phasmatidae are a family of the stick insects. They belong to the superfamily Anareolatae of suborder Verophasmatodea.
Eurycnema goliath, commonly known as the goliath stick insect, or the regal stick insect, is a large species of stick insect in the family Phasmatidae, endemic to Australia and considered one of the largest species of stick insects in the country. The species has the Phasmid Study Group number PSG14.
The pink-winged phasma is a species of stick insect that is endemic to Australia.
SS Makambo was a steamship first owned by Burns Philp & Co. Ltd. She was built in Port Glasgow in Scotland and named after an island in the Solomon Islands. She carried both passengers and cargo and was principally used on routes between eastern Australia and islands in Melanesia and the Tasman Sea. In November 1908 Jack and Charmian London travelled from Guadalcanal to Sydney on the Makambo after abandoning their ill-fated circumnavigation of the world on the Snark, a 45' sailing yawl.
Ctenomorpha marginipennis, the margin-winged stick insect, is a species of stick insect endemic to southern Australia. The species was first described by George Robert Gray in 1833.
Melaleuca howeana, commonly known as tea tree, is a plant in the myrtle family, Myrtaceae and is endemic to the Lord Howe Island group, 600 km (400 mi) off the east coast of Australia. It is common in exposed areas, on cliffs and ridges, occasionally forming pure stands. Its closest mainland relative is Melaleuca ericifolia.
D. australis may refer to:
Pulchriphyllium giganteum, commonly known as the Giant Malaysian Leaf insect, is a species of leaf insects described from Malaysia by Hausleithner in 1984 and placed in the genus Pulchriphyllium since 2021. Pulchriphyllium giganteum is the largest species belonging to the genus Pulchriphyllium reaching 105 mm in size. They are found most abundantly in the west Malaysian tropics. The females typically have large elytra that lie edge to edge on the abdomen and tend to lack hind wings making them usually flightless. Males have small elytra and sometimes transparent non-leaflike functional hind wings. Pulchriphyllium giganteum found in the wild tend to be mostly females and the first male of this species was not found until 1994. In captivity, the species has primarily been observed to reproduce through parthenogenesis meaning the females are asexual. The primary reproductive pattern in the wild is unknown. Eggs tend to be brown or black and glossy and resemble seeds. They hatch around 6 months after breeding. Newly hatched young nymphs tend to be wingless and brown or reddish in color. They develop their green color after feeding on leaves. Both the adult and larval stages are phytophagous meaning they feed on plants. The main plant food sources for this species are oak and bramble tree leaves.
Acanthoxyla inermis is an insect that was described by John Salmon in 1955. Acanthoxyla inermis is included in the genus Acanthoxyla, and family Phasmatidae. No subspecies are listed. This species is native to New Zealand but has been unintentionally moved to Great Britain where it has grown a stable population and is the longest insect observed, and the most common of the stick insects that have established themselves on the island.
Eurycantha horrida, the thorny devil walking stick, is a species belonging to the stick insects and to the family Phasmatidae.
Trachyaretaon is a genus of stick insects native to the Philippines.
Eubulides is a stick insect genus native to the Philippines.
Panesthia lata, the Lord Howe Island wood-feeding cockroach or Lord Howe Island cockroach, is a large, wingless cockroach species endemic to the Lord Howe Island Group in the Tasman Sea.
1 2 3 Priddel, D.; Carlile, N.; Humphrey, M.; Fellenberg, S.; Hiscox, D. (July 2003). "Rediscovery of the 'extinct' Lord Howe Island stick-insect (Dryococelus australis (Montrouzier)) (Phasmatodea) and recommendations for its conservation". Biodiversity and Conservation. 12 (7): 1391–1403. doi:10.1023/A:1023625710011. S2CID20545768.
↑ Honan, Patrick (2008). "Notes on the biology, captive management and conservation status of the Lord Howe Island Stick Insect (Dryococelus australis) (Phasmatodea)". J. Insect Conserv. 12 (3–4): 399–413. doi:10.1007/s10841-008-9162-5. S2CID34793618.
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