''Amychus granulatus'', commonly known as the Cook Strait click beetle, is a large flightless

click beetle Elateridae or click beetles (or "typical click beetles" to distinguish them from the related families Cerophytidae and Eucnemidae, which are also capable of clicking) are a family of beetles. Other names include elaters, snapping beetles, spr ...

in the family

Elateridae Elateridae or click beetles (or "typical click beetles" to distinguish them from the related families Cerophytidae and Eucnemidae, which are also capable of clicking) are a family of beetles. Other names include elaters, snapping beetles, sp ...

Description

Adult '' A. granulatus'' can be distinguished from other ''Amychus'' species by its wide and spreading prothorax and small round nodules on its elytra. Its size ranges from 16 to 22.5 mm. It has a flattened body shape and small vestigial wings. Click beetles are named due to their ability to make an audible click when on their back to jump into the air. However, ''Amychus'' do not have the ability to defend themselves in this way.

Distribution

This species was discovered by the lighthouse keeper Andreas Sandager on North Brother Island in

Cook Strait Cook Strait ( mi, Te Moana-o-Raukawa) separates the North and South Islands of New Zealand. The strait connects the Tasman Sea on the northwest with the South Pacific Ocean on the southeast. It is wide at its narrowest point,McLintock, A ...

, and was described by Broun in 1881. It is currently only found on islands in the outer

Marlborough Sounds The Marlborough Sounds are an extensive network of sea-drowned valleys at the northern end of the South Island of New Zealand. The Marlborough Sounds were created by a combination of land subsidence and rising sea levels. According to Māori ...

in New Zealand; fragments of this beetle have been collected from the nest of the extinct

Laughing owl The laughing owl (''Ninox albifacies''), also known as ''whēkau'' or the white-faced owl, was an endemic owl of New Zealand. Plentiful when European settlers arrived in New Zealand, its scientific description was published in 1845, but it was ...

North Canterbury Canterbury ( mi, Waitaha) is a region of New Zealand, located in the central-eastern South Island. The region covers an area of , making it the largest region in the country by area. It is home to a population of The region in its current fo ...

, indicating it once had a much larger former range. Islands that it has been collected from include the Brothers, Stephens Island, Middle and South Trio Island,

Maud Island Maud Island, also called Te Hoiere in the Māori language, is one of the larger islands in the Marlborough Sounds on the northern tip of the South Island of New Zealand, with a total area of . Fauna Maud Island is an important predator free na ...

and Sentinel Rock. It has not been seen since 1957 on North Brother Island (its type locality) despite searches, and it is possible that it is now extinct there. The relict populations on Marlborough Sounds islands are probably due to the introduction of mammalian predators on the mainland.

Ecology

The adult beetle has been collected from tree trunks including tawa, ngaio and taupata at night, and from under logs and rocks. Adult beetles have been observed feeding on sap oozing from tree trunks.

Threats

The presence of five separate populations of the beetle on islands in the Outer Marlborough Sounds probably helps protect it against any immediate threat to its survival. However, some of these populations are in decline. In 1930, G.V. Hudson described the Cook Strait click beetle as "confined to the islands in Cook Strait, where it is abundant in crevices in the rocks and under logs and stones". Recent accounts describe it as now rare, despite little change in the vegetation over the past fifty years. A recent increase in the number of predatory

tuatara Tuatara (''Sphenodon punctatus'') are reptiles endemic to New Zealand. Despite their close resemblance to lizards, they are part of a distinct lineage, the order Rhynchocephalia. The name ''tuatara'' is derived from the Māori language and m ...

may account for this. However tuatara scats, despite containing a rich range of invertebrate fauna, were not shown to contain the Cook Strait click beetle. It is thought that the lack of decomposing logs on Stephens Island may limit the population size there.

Conservation

Since 1980 ''A. granulatus'' has been protected under the Wildlife Act 1953, making it illegal to collect or own specimens without a permit. Its conservation status is considered to be Relict and Conservation Dependent, as it only survives on islands that are maintained as rodent-free. Future conservation efforts, including any captive breeding programme, are impeded by the lack of knowledge of its basic biology, particularly the biology of its larvae. Providing artificial habitat to replace the lack of decomposing logs may assist this species and help with population monitoring.

References

External links

* The Cook Strait click beetle discussed on RNZ's ''Critter of the Week''
9 September 2016
{{Taxonbar, from=Q24257045 Beetles described in 1883 Endemic fauna of New Zealand Beetles of New Zealand Elateridae Endemic insects of New Zealand