EPOW - Ecology Picture of the Week

Behold the Largest Heath

Giant Pandani (Richea pandanifolia), Family Epacridaceae
Cradle Mountain National Park, Tasmania, Australia

Explanation:  Stretching taller than me is this giant of the herb world.  These "trees" are giant pandani, also called giant grass trees, growing here in the amazing high-elevation world of Cradle Mountain National Park on the island state of Tasmania, Australia.  

This is the tallest heath plant in the world.  It looks like an agave or a yucca, or maybe a silversword gone made with growth hormones, growing as tall as 12 meters (nearly 40 ft)!  And this species is found only here, in Tasmania ... an example of "insular gigantism," where some life forms on isolated islands evolve into huge size, usually because of the lack of predators, herbivores, and competitors.  

We are in an alpine heathland, a land with a high diversity of heath plants, but this one towers over all.  Heaths are usually small plants that hug the ground, and heathlands also have a variety of other plants as well, including grasses, shrubs, and conifer trees.  

But more on our heath giant.  Research has revealed that not only is the plant a giant, but so is a species of moth associated with the plant.  The moth is called, appropriately, the "giant Tasmanian pandani moth" or Proditrix nielseni (of order Lepidoptera, family Plutellidae).  The larvae (caterpillars) of this moth, only recently described from these Tasmanian montane ecosystems, feed in the crown of the giant pandani plant.  This was the first record of this moth genus in Australia, and it might be a new, undescribed species as compared to the moths of this same genus found in New Zealand.  

Islands are wonderful "natural evolutionary and ecological laboratories!"
  

Information
    McQuillan, Peter B.  2003.  The giant Tasmanian 'pandani' moth Proditrix nielseni, sp. nov. (Lepidoptera : Yponomeutoidea : Plutellidae s. l.).  Invertebrate Systematics 17(1):59-66.