Mating is tough for ringlet

Dr George Gibbs feels sorry for a forest ringlet butterfly looking for a mate.

The highly attractive butterfly was common in New Zealand as recently as 40 years ago.

Gibbs has been studying a population in Days Bays for 15 years. In that time, he has seen it go from a healthy population to being on the brink of extinction.

A research associate at Victoria University School of Biological Sciences, Gibbs is regarded as an expert on New Zealand butterflies but is baffled by their decline.

‘‘They were certainly really common when I was a kid, that was in the 1950s, you could go out and see a couple of dozen,’’ he said.

In the Wellington region they were common in the Rimutaka Forest Park and in the hills above Eastbourne.

The population he studies is on the ridge above Days Bays and the decline has been dramatic.

‘‘Now I am down to seeing one or two … they have been at that low level for five years, I am amazed they are hanging on.’’

The few he does see must have a hard time finding each other and he believed it was only a matter of time before the population became extinct.

‘‘They bugger off and look for a mate, which must be hard work.’’ So why are the ringlets disappearing? ‘‘I just don’t know,’’ Gibbs said. Theories range from wasps, particularly German wasps, to the loss of habitat and pesticides.

Gibbs suspected introduced wasps were the cause but there was no research to support that view. ‘‘They are certainly under suspicion.’’ Ringlets lived in native bush, which made pesticides an unlikely explanation and their favoured food, a variety of cutty grass, was also still common.

A generation of New Zealanders have grown up without seeing a ringlet and Gibbs admitted he was gloomy about their future.

‘‘It is one of the most stunning insects we have and yet people never see it.’’

The Moths and Butterflies of New Zealand Trust is bringing out expert Steve Wheatley from England to advise on how best to save the species.

Gibbs backed that approach but said it would be hard to find a solution without knowing the reasons behind their rapid decline.