Time flies when you’re having fun

People say time flies when you retire, but Otago Museum’s Honorary Curator of Entomology, Associate Professor Steve Kerr is taking that literally. He has been rekindling a childhood love of studying insects and spends his days in nature around Otago looking for flies. “I just think they are fascinating”, said Professor Kerr, “New Zealand has species that you can’t see anywhere else; they are incredibly diverse”.

Professor Kerr has just published the first ever scientific description of a new indigenous species of fly from the family Empididae. We currently don’t know much about the ecological role of these native flies, but the larvae of species elsewhere prey on other insects and scavenge in streams and the adult flies are likely to be important pollinators.

Professor Kerr has named the new fly Empidadelpha pokekeao. Distinct colouration of the body and legs as well as uniquely long antenna defines this new fly. It has smoky wings with a distinct dark cloudy patch at the end of the wing, after which the species was named. The species name, pokekeao, means ‘dark cloud’ in te reo Māori.

He first found this fly at Sullivan’s Dam near Dunedin in December 2017 while out enjoying his favourite pastime, photographing insects. “This little fellow was tiny, but he sat perfectly still and seemed to love the camera!”, said Professor Kerr. He caught the fly and took it home so he could further identify what species it was.

After a couple of years of work, which involved researching many very old research papers and visiting other New Zealand museums making comparisons to similar related species, Professor Kerr and fellow entomologist James Tweed from Ahika Consulting discovered no one had ever described it before. It was a brand-new species to science in the genus Empidadelpha, which previously comprised just three species: two from New Zealand and one from Southern Chile.

This inconspicuous little fly has so far only been found in the Lower South Island with individuals being found at Sullivan’s Dam in Dunedin, Macrae’s Flat, and near Lake Brunner on the West Coast. Steve and James suggest that these flies are on the wing in late spring and early summer and inhabit riparian margins around streams and water sources. No females of this species have ever been found, so keep an eye out for the mate of the specimens that we have at Otago Museum!

Dr Kerr is continuing his hobby and collected so many flies last summer that his family had to schedule shopping trips for when the freezer had room for something other than insects. “We were processing so many, it was pretty full at times”, he laughed.

Empidadelpha pokekeao will be the third species that Dr Kerr has found and formally described, and he hopes not the last. There are still many species of invertebrates to be found and described in Aotearoa. The descripition of this new species is now available on-line in the journal New Zealand Entomologist.

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