Jump to content

Huhu beetle

From Wikipedia, the free encyclopedia

"Huhu" redirects here. For the local-level government area in Papua New Guinea, see Huhu Rural LLG.

Huhu beetle
Prionoplus reticularis illustration by Des Helmore
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Coleoptera
Suborder: Polyphaga
Infraorder: Cucujiformia
Family: Cerambycidae
Subfamily: Prioninae
Tribe: Anacolini
Genus: Prionoplus
Species:
P. reticularis
Binomial name
Prionoplus reticularis
White, 1843

The huhu beetle (Prionoplus reticularis) is a longhorn beetle endemic to New Zealand. It is the heaviest beetle found in New Zealand.

Taxonomy

[edit]

The first specimen of huhu beetle to be used for taxonomic purposes was collected by Andrew Sinclair during a voyage where he visited Bay of Islands and went on botanical expeditions alongside William Colenso and Joseph Dalton Hooker. The specimens he collected from this trip were donated to the British Museum (now Natural History Museum of London). [1][2] From the specimen Sinclair collected, zoologist Adam White formally described the species in 1843. The type specimen is stored in the Natural History Museum of London.[2]

The huhu beetle larvae and pupa were later described by Thomas Broun in 1880 and a brief description of their typical habits were given from specimens collected in Whangarei.[3] Broun then went on to produce a revised description of the species in his landmark “Manual of the New Zealand Coleoptera” publication in the same year.[4]

Etymology

[edit]

The Māori name huhu is ultimately Austronesian in origin from root form *bukbuk₃, where cognates in related languages (like Tagalog bukbok) refer to weevils known to infest wood and rice across tropical Southeast Asia.[5]

In Māori, huhu has semantically evolved to refer explicitly to its larval form (also tunga haere, tunga rākau).[6] As the huhu larva reaches maturity it ceases to bore in wood and casts its skin. This still edible stage is known in Māori as tataka. It then develops wings and legs, and while it is still white, it is known as pepe or pepe-te-muimui.[7][6] Finally, it emerges and flies off to reproduce and is known as tunga rere.[6]

Description

[edit]
Adult huhu beetle

Adults

[edit]

Adult huhu beetles are unmistakable and are easily identified by their large size (reaching around 5cm in length) and distinctive appearance.[8]

Overall, the whole body of the adult is a dark brown colour. The head and thorax have a thick layer of brown hairs that make it appear somewhat fuzzy. As is typical of long horn beetles, the antennae are long, extending around three quarters of the beetle's length. The mandibles are large and curved with a sharp end. Spines are present on the legs on the femur and tibia segments. The elytra is coloured brown and has three pale yellow veins running down the length of the elytra with numerous cross veins forming a reticulated pattern.[4][2]

Huhu beetle larvae

Larvae

[edit]

The larvae are very large, reaching up to 50-70mm in length before maturation. They are coloured creamy white and have a robust cylinder shape. The larvae have a well developed head capsule with visible mandibles which are black and shining in colour. [9]

Eggs

[edit]
Huhu beetle eggs

Eggs are around 3mm in length and 1.2mm wide. They are coloured white and are shaped like cigars. The surface is unsculptured.[9]

Life cycle

[edit]

Female adult huhu beetles oviposit their eggs in clutches of 10–50, though up to 100 may be found.[10][11][12] Eggs are laid in cryptic sites or in cracks in the bark of fallen wood.[12] In laboratory conditions of 20°C ± 2°C and a relative humidity of c. 75%, eggs hatched in 23 ± 2 days.[12]

Before hatching, the larva can be seen to move inside the egg and will break free from the egg using its mandibles to pierce the chorion of the egg and then enlarging the opening by chewing, although the chorion itself is not ingested.[12] Setae that are found on abdominal segments 1-6 assist in providing support as the larva leaves the egg and excavates the initial gallery.[12]

Huhu beetle larvae feeding on rotting wood

The whitish-coloured larvae normally feed on dead wood of gymnosperms (mainly native and introduced conifers) associated with lowland podocarp forest.[13] Larval duration of P. reticularis is two to three years in the wild.[10] Under laboratory conditions, larval duration has been reduced to c. 250 days using an artificial diet and maintaining a temperature of 20°C.[14] In its final instar the larva moves to within 7.5–10cm of the surface of the wood before constructing the pupal chamber.[12] The pupal chamber is constructed by enlarging the diameter of the normal gallery over a period of one to three days. This process creates fragments of wood similar to wood shavings about 3cm by 1cm in size which are then packed into the larval gallery to form a plug.[12] Once the plug is completed the larva lines the walls of the pupal chamber with the last frass voided from its gut.[12] The larva then undergoes a resting period of around ten to fifteen days where the abdominal segments contract and the body darkens slightly whereupon it moults into a pupa.[12]

Huhu beetle pupae

The pupal phase lasts around 25 days with gametogenesis being completed during this stage.[12][15] Eclosion occurs with a rupture along the frontal suture followed by a longitudinal rupture to the posterior border of the mesothorax.[12] The head, feet and wings are freed during arching movements of the body through the ruptured cuticle.[12] The emerged adult may then enter an inactive period of three to five days prior to creating an exit tunnel out of the pupal cavity.[12]

Following pupation and emergence, the adult beetle does not eat and lives for approximately two weeks.[6]

Hosts

[edit]

As previously discussed, the larvae of huhu beetles live and feed on the decaying wood of gymnosperms. There are currently twelve gymnosperm species that are known to act as hosts to the larvae. Additionally, there are also two host records of larvae living in angiosperms. They have been reported to occur in tawa and oak, although the latter record is likely a misidentification.[13]

List of huhu beetle recorded gymnosperm hosts:[13]

Distribution

[edit]

The huhu beetle is endemic to New Zealand. It is widespread throughout the main islands, occurring from sea level up to altitudes of 1400m.[16][17] There is a single record of a huhu beetle caught in the Kermadecs on Raoul Island. Visiting researchers have searched rotting wood for signs of huhu beetle larvae, but none were found, indicating that it has not established on the island. Because of this, it has been assumed that the specimen was from untreated wood brought to the island and used for construction.[18]

Behaviour

[edit]

The beetles are nocturnal and are attracted by the lights of dwellings as noted by Hudson in 1892 "it is greatly attracted to light, and this propensity frequently leads it on summer evenings to invade ladies' drawing-rooms, when its sudden and noisy arrival is apt to cause much needless consternation amongst the inmates".[19][20] They have powerful mandibles, which can produce a painful bite.

Adult females of P. reticularis produce an olfactory cue which attract adult males to the female.[21] Adult individuals of both sexes will show a display behaviour if disturbed with the head jutting forward, mandibles opening to their full extent, antennae flailing and the head being raised and lowered.[21] High intensity displays between individuals may lead to combat with preliminary grappling occurring with fore legs which usually results in an individual being thrown onto its back. Any object coming into contact with the mandibles is seized frequently resulting in the loss of appendages.[21]

Gut microbiome

[edit]

In one study, the gut of huhu beetles was found to harbour a diverse range of microorganisms such as Acidobacteriaceae, Burkholderiaceae and Enterobacteriaceae. It was inferred that a large proportion of the microorganisms detected were involved in the digestion process.[22]

The gut microbiome diversity is also dependent on the food source the larvae has access to. When fed on a diet of just cotton, a cellulose rich food source, the gut microbiome develops a high abundance of cellulose degraders. Conversely, when given a diet of pine wood, the gut microbiome had a high level of microorganisms such as Scheffersomyces, which are known to digest plant cell walls.[23]

As food

[edit]
Advertising cooked huhu grubs at the Hokitika Wildfoods Festival 2021

The larvae of P. reticularis are edible to humans, with a long history of indigenous consumption, and their flavour has been described as like buttery chicken[24] or peanut butter.[25] There are different names in Māori for grubs at different stages of development, for example young larvae still actively feeding on timber are called tunga haere or tunga rākau, while full grown grubs which have ceased to feed and are preparing to pupate are called tataka and are the most prized (because there is no undigested wood pulp inside of them at this point). Huhu grubs may be consumed either raw or traditionally cooked in a hāngī, and are an especially rich source of fat in the New Zealand wilderness.[26]

P. reticularis contains substantial amounts of nutrients. The larvae and pupae are relatively high in fat (up to 45% and 58% dry weight in large larvae and pupae respectively).[27] The fat in huhu grubs is mostly oleic acid and palmitic acid.[27] The second most abundant nutrient is protein, which is present at 30% dry weight in the large larvae, and close to 28% dry weight in the pupae.[27] Protein extracts from huhu larvae and pupae are high in essential amino acids such as isoleucine, lysine, leucine, and valine.[28] The total essential amino acid content of huhu grubs meets the WHO essential amino acid requirements for human nutrition.[28] The essential amino acid content of huhu is significantly higher than that of mealworms, and is comparable to beef and chickpeas.[28] When reconstituted in water, the protein powders of huhu larvae and pupae are able to form stable foams and emulsions. The ash content (representing minerals) of huhu grubs is 1.8% dry weight in large larvae, and 2.2% in pupae.[27] The minerals include manganese, magnesium, phosphorus, iron, copper, and zinc.[29]

Predators and parasites

[edit]

Huhu beetles are known to be preyed upon by a wide range of predators. Some such predators are introduced to New Zealand, such as ship rats,  little owl and magpie.[30][31] Native predators are known to include short tailed bats, moreporks and saddleback.[32][30][33] Before their extinction, Huia were observed to utilise huhu beetle larvae as their principle food source.[34]

As larvae, huhu beetles are known to be preyed upon by the larvae of Thoramus wakefieldi, despite the relative small size of T. wakefieldi when compared to huhu beetle larvae.[35] The larvae are also known to be preyed upon by of Rhipistena cryptarthra.[36]

Parasites

[edit]

Huhu beetles are the only known hosts of Prionaphes depressus, which lay their offspring in the eggs of the beetles.[37]

See also

[edit]

References

[edit]
  1. ^ "Sinclair, Andrew | Dictionary of New Zealand Biography | Te Ara". teara.govt.nz. Retrieved 5 July 2025.
  2. ^ a b c Dieffenbach, Ernst; Dieffenbach, Ernst (1843). Travels in New Zealand with contributions to the geography, geology, botany, and natural history of that country. London: J. Murray. doi:10.5962/bhl.title.25939.
  3. ^ Broun, T. 1880 (1879): On the habits of Prionoplus reticularis with diagnoses of the larva and pupa. Transactions and proceedings of the New Zealand Institute: 12(15):284-288
  4. ^ a b Broun, Thomas.; Broun, Thomas; Museum (N.Z.), Colonial; Institute, New Zealand (1880). Manual of the New Zealand Coleoptera. Wellington: Printed at the Office of James Hughes, Lambton Quay. doi:10.5962/t.173101.
  5. ^ Blust, Robert; Trussel, Stephen (2010). "*bukbuk₃ - weevil that infests wood, bamboo, and rice". Austronesian Comparative Dictionary. Retrieved 25 December 2024.
  6. ^ a b c d Best, Elsdon (1902). "Art. V.—Food Products of Tuhoeland: being Notes on the Food-supplies of a Non-agricultural Tribe of the Natives of New Zealand; together with some Account of various Customs, Superstitions, &c., pertaininy to Foods". Transactions and Proceedings of the Royal Society of New Zealand. 35: 64. Retrieved 20 August 2011.
  7. ^ "pepe-te-muimui". maoridictionary.co.nz. Retrieved 3 September 2017.
  8. ^ "Huhu beetle". Manaaki Whenua. Retrieved 6 July 2025.
  9. ^ a b Dumbleton, L.J. 1957: The immature stages of some New Zealand longhorn beetles. (Coleoptera - Cerambycidae). Transactions of the Royal Society of New Zealand: 84(3):611-628
  10. ^ a b Miller, David; Walker, Annette (1984). Common Insects in New Zealand (Rev. ed.). Wellington [NZ]: Reed. ISBN 0589014803. OCLC 12748887.
  11. ^ "Huhu beetle (Prionoplus reticularis) or tunga rere". Te Papa. 1998. Retrieved 14 May 2025.
  12. ^ a b c d e f g h i j k l m Edwards, John S. (1961). "Observations on the biology of the immature stages of Prionoplus reticularis White (Col. Ceramb.)". Transactions of the Royal Society of New Zealand. 88: 727–731 – via Papers Past.
  13. ^ a b c Edwards, John S. (1959). "Host range in Prionoplus reticularis White" (PDF). Transactions of the Royal Society of New Zealand. 87 (Parts 3 and 4): 315–318.
  14. ^ Rogers, David J.; Lewthwaite, Sonya E.; Dentener, Peter R. (2002). "Rearing huhu beetle larvae, Prionoplus reticularis (Coleoptera: Cerambycidae) on artificial diet". New Zealand Journal of Zoology. 29 (4): 303–310. doi:10.1080/03014223.2002.9518314. ISSN 0301-4223. S2CID 84043980.
  15. ^ Edwards, John S. (1 December 1961). "On the reproduction of Prionoplus reticularis (Coleoptera, Cerambycidae), with general remarks on reproduction in the Cerambycidae". Journal of Cell Science. s3-102 (60): 519–529. doi:10.1242/jcs.s3-102.60.519. ISSN 0021-9533.
  16. ^ "NZ Farm Forestry - Huhu beetle". www.nzffa.org.nz. Retrieved 6 July 2025.
  17. ^ Edwards, J.S. 1961: Observations on the ecology and behaviour of the huhu beetle, Prionoplus reticularis White (Col. Ceramb.). Transactions of the Royal Society of New Zealand: 88(4):733-741
  18. ^ Watt, J.C. 1975: Some Coleoptera from the Kermadec Islands. New Zealand entomologist: 6(1):50-55
  19. ^ "Huia". The Official World Wildlife Fund Guide to Extinct Species of Modern Times. Vol. 1. Beacham Publishing. 1997. pp. 63–65.
  20. ^ Hudson, G. V. (George Vernon) (1892). An elementary manual of New Zealand entomology; being an introduction to the study of our native insects. Smithsonian Libraries. London, West, Newman & Co.
  21. ^ a b c Edwards, John S. (1961). "Observations on the ecology and behaviour of the huhu beetle, Prionoplus reticularis White.(Col. Ceramb.)". rsnz.natlib.govt.nz. Transactions and Proceedings of the Royal Society of New Zealand. pp. 733–741. Retrieved 11 July 2018.
  22. ^ Reid, Nicola M.; Addison, Sarah L.; Macdonald, Lucy J.; Lloyd-Jones, Gareth (2011). "Biodiversity of Active and Inactive Bacteria in the Gut Flora of Wood-Feeding Huhu Beetle Larvae (Prionoplus reticularis)". Applied and Environmental Microbiology. 77 (19): 7000–7006. Bibcode:2011ApEnM..77.7000R. doi:10.1128/AEM.05609-11. PMC 3187079. PMID 21841025.
  23. ^ Viswam, Jay; Baptista, Mafalda; Lee, Charles K.; Morgan, Hugh; McDonald, Ian R. (2 July 2024). "Investigating the lignocellulolytic gut microbiome of huhu grubs ( Prionoplus reticularis ) using defined diets and dietary switch". PeerJ. 12 e17597. doi:10.7717/peerj.17597. ISSN 2167-8359. PMC 11225714. PMID 38974417.
  24. ^ "Weird Food from around the World". 2008. Archived from the original on 18 July 2008. Retrieved 18 July 2008.
  25. ^ Gibbs, George (2007). "Insects – overview - In the bush". Te Ara - the Encyclopedia of New Zealand. Retrieved 12 February 2019.
  26. ^ "Huhu on the menu". Te Papa-Tai Awatea/Knowledge Net. 22 January 2016. Archived from the original on 13 April 2017. Retrieved 12 February 2019.
  27. ^ a b c d Kavle, Ruchita Rao; Carne, Alan; Bekhit, Alaa El-Din Ahmed; Kebede, Biniam; Agyei, Dominic (1 July 2022). "Proximate composition and lipid nutritional indices of larvae and pupae of the edible Huhu beetle (Prionoplus reticularis) endemic to New Zealand". Journal of Food Composition and Analysis. 110 104578. doi:10.1016/j.jfca.2022.104578. ISSN 0889-1575. S2CID 248209931.
  28. ^ a b c Kavle, Ruchita Rao; Nolan, Patrick James; Bekhit, Alaa El-Din Ahmed; Carne, Alan; Morton, James David; Agyei, Dominic (2023). "Physicochemical Characteristics, Techno-Functionalities, and Amino Acid Profile of Prionoplus reticularis (Huhu) Larvae and Pupae Protein Extracts". Foods. 12 (2): 417. doi:10.3390/foods12020417. ISSN 2304-8158. PMC 9857897. PMID 36673509.
  29. ^ Kavle, Ruchita Rao; Carne, Alan; Bekhit, Alaa El-Din Ahmed; Kebede, Biniam; Agyei, Dominic (2022). "Macronutrients and mineral composition of wild harvested Prionoplus reticularis edible insect at various development stages: nutritional and mineral safety implications". International Journal of Food Science & Technology. 57 (10): 6270–6278. doi:10.1111/ijfs.15545. ISSN 0950-5423.
  30. ^ a b Edwards, J.S. 1961: Observations on the ecology and behaviour of the huhu beetle, Prionoplus reticularis White (Col. Ceramb.). Transactions of the Royal Society of New Zealand: 88(4):733-741
  31. ^ Daniel, M.J. 1973: Seasonal diet of the ship rat (Rattus r. rattus) in lowland forest in New Zealand. Proceedings. New Zealand Ecological Society: 20:21-30
  32. ^ Daniel, M.J. 1979: The New Zealand short-tailed bat, Mystacina tuberculata; a review of present knowledge. New Zealand journal of zoology: 6(2):357-370
  33. ^ Smith, W.W. 1889 (1888): On the birds of Lake Brunner district. Transactions and proceedings of the New Zealand Institute: 21:205-224
  34. ^ Buller, W.L. 1870: On the structure and habits of the huia (Heteralocha gouldi). Transactions and proceedings of the New Zealand Institute: 3(2):24-29
  35. ^ Murray, L. 1973: Predation on Prionoplus reticularis (Cerambycidae) by Thoramus wakefieldi (Elateridae). New Zealand entomologist: 5(3-4):360-362
  36. ^ Hudson, G.V. 1934: New Zealand beetles and their larvae: an elementary introduction to the study of our native Coleoptera. Ferguson & Osborn ltd, Wellington: 236 PP
  37. ^ Hincks, W.D. 1961: A new mymarid (Hym., Mymaridae) genus from Prionoplus reticularis White. Transactions of the Royal Society of Ne w Zealand: zoology: 1(12):159-161
[edit]
Wikispecies has information related to Huhu beetle.
Wikimedia Commons has media related to Prionoplus reticularis.
Retrieved from "https://en.wikipedia.org/w/index.php?title=Huhu_beetle&oldid=1299150492"