Grass grub beetles invade Bay in numbers

Locals have been wondering what caused the influx of beetles in the Bay this week. Photo/Supplied.

Australians are invading Hawke's Bay - in the form of the Tasmanian grass grub.

Bug expert Ruud Kleinpaste said the bugs took flight about this time of year to mate and said this year was no different, although it may just be a particularly large cluster.

"It happens every year but this is probably a bad year, or a good year if you're a grass grub," he said.

Adult beetles, coloured dark brown or black, fly in large numbers from January to March and are strongly attracted to lights.

Mr Kleinpaste recalled walking across "carpets" of the bugs during the late 80s about March.

"Their hatching is a matter of timing in the year. Now's the time to become an adult beetle and fly," he said.

Locals took to social media this week to speculate the cause of masses of black bugs in the region; some speculating it was the fire driving them from the hills.

While Mr Kleinpaste ruled out that this week's fires were the reason the bugs were so plentiful, he did say the beetles would flee smoke and were capable of travelling great distances.

"They have seriously sensitive antennas that pick up anything in the air, and if there's smoke in the air they'll go away from it and avoid it," he said.

Mr Kleinpaste said the influx of bugs would "absolutely" be welcomed by animals who eat them.

"All the birds that eat insects will feast on these things and so on."

Mr Kleinpaste said he did not understand why locals were complaining about the bugs.

"You don't hear these beetles complaining about the people running away from the fires. And here comes the best point of all; these beetles have been here for, say, two million years longer than we have. We built Napier, Hastings and Havelock North - their habitat. Now did they complain when we buggered their habitat? They said 'No, don't worry about a thing. We'll come and live on your lawn if you don't mind'," he said.