Acanthoxyla prasina, the prickly stick insect, is a stick insect in the order Phasmatodea and the family Phasmatidae.[1] It is native throughout New Zealand, although it is less frequently reported than "common" stick insect species. It has been introduced to Britain, predominantly Cornwall and Devon, and to the south-west region of the Republic of Ireland.[2][3] It has a thorny skin, which is used as camouflage.[4]
| Prickly stick insect | |
|---|---|
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Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Insecta |
| Order: | Phasmatodea |
| Family: | Phasmatidae |
| Genus: | Acanthoxyla |
| Species: | A. prasina
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| Binomial name | |
| Acanthoxyla prasina (Westwood, 1859)
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| Synonyms | |
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Identification
editAcanthoxyla prasina is a large insect; their body length ranges from 7.5 to 11 cm long when fully grown as adults.[5] Their bodies tend to be wider than other stick insect species. They come in two different colour forms: green and brown in various shades. There are eight subspecies, some of which have prominent dark spines on the top of the thorax and abdomen.[6] Acanthoxyla prasina have various number and size of their spines (prickles) including one characteristic spine on the underside of their abdomen, at the base of their subgenital plate.[6] Acanthoxyla prasina has black spines across the top of individuals of A. prasina heads, mesothorax, metathorax, abdomen and femora.[6] Their antennae are on average just slightly longer than the fore femora and the tail on the end of their abdomen is shorter and more circular than that of other subspecies.[6] Camouflage, body structures and behaviors help A. prasina avoid predation.[7]
Life cycle and phenology
editAcanthoxyla prasina has no male individuals; A. prasina are exclusively females. They reproduce through asexual reproduction called parthenogenesis.[8] Prickly stick insects lay eggs that are 4.2 mm long and 1.8 mm high.[5] Their eggs are brown/grey, oval shaped and are covered in small spines. Female stick insects lay their eggs on the ground, and they begin to hatch in spring when the weather warms.[9] Each individual will lay hundreds of eggs in its lifetime but all the eggs that are laid have a 99% mortality rate.[3]
Hatchlings emerge as nymphs. At one day old they are approximately 2 cm long.[5] Ananthoxyla prasina will moult approximately 5–6 times in roughly 6 months before reaching adult size.[10] They usually moult at night. Once emerged, they will likely eat their old skin. Insects in the genus Acanthoxyla live for 12–24 months.[9]
Distribution and habitat
editNative range
editAcanthoxyla prasina can be found throughout New Zealand, where it was originally endemic.[11]
Introduced range
editAnanthoxyla prasina was accidentally introduced to Paignton, UK, in 1910,[12] although other sources describe them as Acanthoxyla subspecies, not Acanthoxyla prasina,[3] or as the smooth stick insect Clitarchus hookeri.[13]
No male had ever been seen within the species or genus Acanthoxyla until 2016 when one was discovered in Cornwall.[13] This single male was the result of a rare mutation. It is unknown if the male was capable of producing sperm or inseminating females because the specimen was killed, dried and added to the collection at the Natural History Museum in London.[14]
Diet
editAcanthoxyla prasina are forage feeders.[8] These stick insects feed on a variety of native plants, as well as some introduced species coniferous trees; radiata pine, macrocarpa, cypress and common garden plants.[6] Acanthoxyla prasina are nocturnal; they usually feed at night.[8]
Predators
editBirds are the most common predator of A. prasina. Many native and introduced species feed on A. parsina, including house sparrows, blackbirds, silvereyes, chaffinches and yellowhammers.[9]
Māori Significance
editMuch of the knowledge and wisdom from the tangata whenua of New Zealand about stick insects has been scattered or lost.[6][7] Stick insects were considered to be relatives of mantids and were called rō, whe and wairaka.[6] Different tribes had their own stories and beliefs involving insects. If a stick insect or mantis crawled onto a woman, it indicated she was pregnant and the type of insect was an indicator of the child's sex.[6] When a mantis or stick insect fell onto a human in a forest, the area became a sacred site.[6] Māori believed the presence of a stick insect would indicate that the land would not make a good garden.[6] There is also the Māori legend of Tāne, who is considered the creator of insects.[7]
Hybridization
editThe entire Acanthoxyla genus likely evolved by hybridization. This hybrid origin theory is highly likely as the genus contains both diploid and triploid lineages. [6][15] The genus Acanthoxyla may have risen from Clitarchus hookeri through two or more hybridizations.[16] The maternal species could be Pseudoclitarchus sentus or an extinct sexual Acanthoxyla.[16] It has been observed that Acanthoxyla genus has low genetic diversity, suggesting poor differentiation.[16]
See also
editReferences
edit- ^ "Acanthoxyla prasina (Westwood, 1859)". phasmida.speciesfile.org. 2021. Archived from the original on 2016-03-29. Retrieved 2021-03-07.
- ^ "Acanthoxyla prasina (National Biodiversity Network Atlas)". nbnatlas.org. 2021. Retrieved 2021-07-17.
- ^ a b c Lee, Malcolm (1998). "An updated survey of the distribution of the stick insects of Britain" (PDF). Phasmid Studies. 7 (1): 18–25. Retrieved 2024-04-02.
- ^ "Insect poses prickly questions" on Otago Daily Times website, viewed 2013-10-16
- ^ a b c Salmon, John Tenison (1991). The Stick Insects of New Zealand. Reed. ISBN 0790002116.
{{cite book}}: CS1 maint: date and year (link) - ^ a b c d e f g h i j k Trewick, Steve (2005). Stick insects. Auckland N.Z: Reed. ISBN 186948570X.
{{cite book}}: CS1 maint: date and year (link) - ^ a b c Trewick, Steve (2007). "Stick insects". Te Ara.
- ^ a b c Buckley, Thomas (2024). "Stick insects (Phasmatodea)". Manaaki Whenua Landcare Research.
- ^ a b c Chudleigh, Brian (2007). "STICK INSECTS: The skinny world of stick insects". New Zealand Geographic. 083.
- ^ "Prickly Stick Insect Acanthoxyla prasina". Entomological Society of New Zealand. 2023-06-03. Retrieved 2023-06-03.
- ^ "Species Details". New Zealand Threat Classification System (NZTCS). 2023-06-03. Retrieved 2023-06-03.
- ^ Salmon, John (1955). "Stick Insects". Tuatara: Journal of Biological Society. 5 (3).
- ^ a b Brock, Paul D; Lee, Malcolm; Morgan-Richards, Mary; Trewick, Steven A (2017). "Missing stickman found: the first male of the parthenogenetic New Zealand phasmid genus Acanthoxyla uvarov, 1944, discovered in the united kingdom". Acropos (60): 16–23. ISSN 1478-8128. Retrieved 2021-07-17.
- ^ ainge Roy, Eleanor (2018-02-06). "New Zealand female-only stick insect produces 'rogue' male in UK". The Guardian. Retrieved 2021-07-17.
- ^ Myers, S., Trewick, S., & Morgan‐Richards, M (2012). "Multiple lines of evidence suggest mosaic polyploidy in the hybrid parthenogenetic stick insect lineage Acanthoxyla". Insect Conservation and Diversity. 6 (4): 537–548. doi:10.1111/icad.12008.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ a b c Morgan-Richards, M., & Trewick, S (2005). "Hybrid origin of a parthenogenetic genus?". Molecular Ecology. 14 (7): 2133–2142. doi:10.1111/j.1365-294X.2005.02575.
{{cite journal}}: CS1 maint: multiple names: authors list (link)
External links
edit
- Acanthoxyla prasina discussed on RNZ Critter of the Week, 17 September 2021