Mistletoe magic and super bees

02:31, Aug 09 2012

How many of you knew that we had native mistletoe? No, not the kind that you kiss under at Christmas, but our own Aotearoa-grown native mistletoe with its own amazing story to tell?

New Zealand has eight remaining native species of mistletoe - and of those all but one are only found here. A ninth species has not been recorded since 1954, so it's most likely now extinct.

Mistletoe are semi-parasitic - they piggyback on other trees and obtain water and nutrients from the host plant, but they can produce their own food through photosynthesis.

Unlike many of our native flowers, some of our mistletoe species (notably the beech mistletoe Peraxilla tetrapetala - or "red mistletoe"), are vibrantly coloured in red (and we have two species of green mistletoe). The fiery red can be spotted in the canopy of our forests from some distance.

Unfortunately, they are also loved by pesky possums, which devour them on a seek-and-destroy mission. Mistletoe are one of the classic "icecream" plants favoured by possums. That is, possums don't just browse evenly over our foliage, they have a range of favoured plants that they will search out and eat every one of, and mistletoe is the "goody gumdrops" of their ice-cream plants.

The other crucial factor for mistletoe survival is the presence of native birds. The mistletoe starts life as a sticky seed nestled in a bird poo which lands in the tops of trees. It needs birds to distribute its seeds, but the native birds play a crucial role in mistletoe reproduction too. The two big red mistletoe species rely in particular on the tui and bellbird to pollinate their flowers. Their flowers are "spring-loaded" with a twist-top lid. A bit like a bottle of fizzy drink, they will explode open, but only if they are opened by the bird with the right-shaped beak. In the case of the Peraxilla mistletoe, the beak of the tui and bellbird is the key to unlock the flower.

However, in 1996 researchers at Canterbury University discovered that we have a couple of species of sneaky and strong native bees which can also pollinate mistletoe flowers. With superhero-like strength, the wee bees can force their way into the flower to get to the goodies inside (cool video of it here). This is a pretty amazing feat given their smallness and the force required to unscrew the mistletoe flower cap. The superbees' attempts at breaking into mistletoe flowers aren't always successful, but it's obviously worth the strain and effort for the times that they do manage to get in. The native bees may actually play a crucial role in mistletoe pollination in areas like the Mackenzie Country where native birds are few and far between.

Have you got mistletoe in your neck of the woods? What species? Did you know about the exploding flowers or superbees?

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