When people hear the word 'fly', they too often react with disgust. They think of houseflies and blowflies and maggots, filth and disease and decay, and they forget most of the important and wonderful things about flies in general. Many hoverflies, for example, have predatory larvae that eat pests like aphids, while the adults help pollinate plants.
The fly in this photograph is also a hoverfly, and to me it epitomises another wonderful thing about flies: many are spectacular, even beautiful. Sadly, I doubt many people have ever seen one of these alive, and of those who have, few would recognise its significance. I only knew to look more closely when I heard the very loud whine made by this fly as it flew low around the base of a giant rimu on the No. 1 Line track. When I got close enough to see the fly clearly, I realised I'd never seen one before. Several times it stopped and crawled into the recesses between the rimu's buttresses, as if searching for something.
I managed to photograph the fly and posted the observation on NatureWatchNZ. Thanks to some thorough investigation by a friend in Otago, who even sought advice from one of the world's foremost experts on hoverflies, we now think this is Helophilus campbelli, which was originally described in 1921 as Myiatropa campbelli. That 1921 description included some diagrams and a low-contrast black-and-white photograph of a pinned specimen, but since then no other photographs appear to have been published — at least not until now. However, seven species of New Zealand Helophilus remain undescribed (we know they're distinct species but no one has published descriptions and names for them), so this might eventually have another change of name.
I still know almost nothing about this fly. What was it doing as it crawled into those recesses? Was it looking for somewhere to lay its eggs? What do its larvae feed on? How common is it? (Not very, if my experience is typical.) The life of this and many other flies remains mostly a mystery, and the opportunity to shed a little light on those lives seems to me to be yet another thing flies offer us. Wouldn't you be delighted to discover something no one knew about a fly as beautiful as this?
All content © 2014 Pete McGregor