Jenny Ladley of the University of Canterbury explains how she discovered that the flowers of the native Peraxilla mistletoe only open when tweaked by certain native birds. This flowering mechanism means that Peraxilla is totally dependent on certain birds for pollination.
Peraxilla mistletoes, they have this special system of explosive flowers that basically the flower has to be popped open by the bird to get the nectar, and they go in and they touch the pollen and the stigma and transfer the pollen between the flowers.
A normal flower starts as a bud and then opens up and so exposes all of the nectar and the sexual parts that want to be visited by the bird or insect, and so that’s what we assumed was going to happen when we started doing the work for the Peraxilla. And normally when you start doing that kind of stuff, you bag the flowers so that you know that nobody else has visited it before you come along and pollinate it. And so that’s what I did with some, and waited for them to open, and waited and waited and waited and they weren’t opening, and the natural ones that weren’t bagged, they were starting to open and so I basically stood there for quite some time and realised there’s tūī up in that area, so you could actually see the tūī popping the flowers open.
We finally worked out that the bird comes along and tweaks them open, and the literature from overseas describes this in some of the African and Australian mistletoes but nobody had recorded it for New Zealand, and so we basically figured out it was doing it here as well.
Funnily enough, when I said to the landowner that this is what’s happening, the old guy that lives there said, “Well what do you mean you found that out? I’ve known that for years,” but it had never been recorded in any literature or anything, but the locals knew.