T.E.R:R.A.I.N - Taranaki Educational Resource: Research, Analysis and Information Network


Beetle (Huhu) Prionoplus reticularis

Kingdom: Animalia 
Phylum: Arthropoda 
Class: Insecta 
Order: Coleoptera 
Family: Cerambycidae 
Subfamily: Prioninae 
Genus: Prionoplus
Species: P. reticularis 
Binomial name: Prionoplus reticularis
Common names: Huhu Beetle, Pepe tunga, Haircutter.

Prionoplus reticularis, is the largest endemic beetle found in New Zealand, a member of the longhorn beetle family Cerambycidae.  A common name for the beetle is haircutter because of the long legs and antenna covered with sharp hooks. If a huhu beetle lands on the hair of a person they become so entangled that scissors must be used for extraction. The beetles are most active at night and are attracted by the lights of the dwelling and only live for about two weeks. They do not feed
The whitish larvae are up to 70 mm long.  Huhu beetle larvae are commonly known as huhu grubs. They hatch from eggs deposited under bark or in crevices in rotten wood. For two to three years they live in cavities they have eaten into the wood, then begin a pupal stage that lasts 25 days. They emerge as flying adult huhu beetles.
For the little grubs to thrive, the moisture content of the wood has to be at least a juicy 25 per cent. They are like tunnel-making machines, but these ones grow as they go, chewing up the timber at their head, digesting it through their system, and excreting it in pellets of 'frass' at the other end. 
Often several generations of larvae will grow themselves through the same piece of timber. The tunnel network becomes more and more intricate and widespread, then broader, then, finally, so eaten through that only a thin outer shell of timber is left. All the holes the grubs make mean that bacteria and fungi can get in too and do their work of rotting away woody rubbish.\
Huhu beetle season is around November to March, with the greatest numbers appearing during midsummer December and January. They get active around dusk, with peak activity around late evening to the middle of the night. Females tend to be more active earlier in the evening they spend considerable periods of the night staying in one place, sending out attractive smells to males, who are of course buzzing around seeking out the attractions.
The  traditional predators of adult huhu beetles was other night fliers such as moreporks. These days, introduced animals such as mice, pigs, and hedgehogs are fond of them and are known to consume them in large numbers. Magpies, being very early morning risers, snap up straggling homegoers.
The grubs are eaten by larvae of two other beetles, and by probing birds like kiwi  The Maori eat tthe grubs raw, roasted or fried and it is also used as fishing bait

The some off  above information is from Te Papa online  at http://tiny.cc/huhu182

More excellent info at
http://www.nzffa.org.nz/farm-forestry-model/the-essentials/forest-health-pests-and-diseases/Pests/Prionoplus-reticularis 

Huhu with ovipositor extended.



Closeup of ovipositor. This organ can extend.



Head and mouth parts of  Prionoplus reticularis 

Huhu with wing case open ready to fly


Photo of Prionoplus reticularis 2mm eggs which are deposited under bark or in crevices in rotten wood.

The photos below are of wood boring larvae of  Prionoplus reticularis








Larva of huhu beetle (underside). Note the two white patches close to the head by which
the larva can be identified.


The mouth parts.




The pupa.found in an excavated cavity in pine wood, This stage lasts for about 25 days.






The undersife of a pupa.


Photo of pupa showing the long ntennae.  Photos below were taken 14 days later after this pupa has shed its skin.


This is a photo of the above pupa 14 days later when it shed its skin. The old skin is visable in the photos.