''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 (biology), family of beetles. Other names include elaters, sna ...

in the family Elateridae.

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 () is a strait that separates the North Island, 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, ...

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

Marlborough Sounds The Marlborough Sounds (Māori language, te reo Māori: ''Te Tauihu-o-te-Waka'') are an extensive network of ria, sea-drowned valleys at the northern end of the South Island of New Zealand. The Marlborough Sounds were created by a combination ...

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'', the laughing jackass, or the white-faced owl, is an Extinction, extinct species of owl that was Endemism, endemic to New Zealand. Plentiful when European settlers arrived in Ne ...

in North Canterbury, 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 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 The tuatara (''Sphenodon punctatus'') is a species of reptile endemic to New Zealand. Despite its close resemblance to lizards, it is actually the only extant member of a distinct lineage, the previously highly diverse order Rhynchocephal ...

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 Elateridae Endemic beetles of New Zealand Beetles described in 1883 Taxa named by Thomas Broun