Red-back spider explosion endangers unique beetle
Spiders endanger unique beetleJO MCKENZIE-MCLEAN
Spirits were high as a voice from down the line cries out "I've found another one".
About a dozen Department of Conservation and Agresearch staff were on hands and knees sifting through piles of dirt taken from 672 core samples of earth last Tuesday for the annual Cromwell Chafer Beetle count.
Last year, disappointingly, only one larvae was found so with a total find of eight this year, Department of Conservation senior ranger Gavin Udy said it was "hugely exciting" for researchers.
These unique insects are found nowhere else in the world but a sandy area covering the equivalent of about 80 rugby fields, known as the Cromwell Chafer Beetle Nature Reserve, on Bannockburn Rd.
The Cromwell reserve, New Zealand's first and only reserve dedicated to protecting an insect, was created in 1983 to help increase beetle numbers.
"Their habitat is very restricted. They like very sandy, fine soils which are only found in Central Otago and only found in this area of Cromwell. There are other Chafer beetles around but this species is unique to Cromwell," Mr Udy said.
Monitoring the population was "hugely important" because the risk of extinction was quite high, he said.
"It would not take much to have some sort of catastrophic event to wipe them out because they are only at this one location."
A threat to the adult beetle currently being studied by an Otago University student was the presence of red-back spiders in the reserve, he said.
"We have seen a massive increase in nests of red-back spiders, which is a cause for concern because they are a major predator of the adult beetle."
More than 200 nests had been found, he said.
"We are unsure of what impact they are having. This will help us understand the impact better . . . indications are (the population) is healthy and stable."
The most larvae found during a count was 12, he said.
- The Mirror
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