Interdependent Fauna and Flora in the Wedderburn environs

Mistletoe is often regarded as a parasite of shrubs and trees however Mistletoe produces its energy through photosynthesis and functions only in a semi-parasitic mode.  Continuing studies are demonstrating the importance of mistletoe for biodiversity in degraded bushland. (Watson D. M. & Herring M 2006)

Too often we see the wonders of fauna or flora as isolated observations and miss the complexity and beauty of the co-evolutionary relationships.  Mistletoe is a good example to illustrate some of these inter-dependencies.

At least four species of Mistletoe occur around the Wedderburn/Mount Korong locality and one, the Grey Mistletoe Amyema quandang can be seen on Cootamundra Wattle Acacia bayleania in gardens around Wedderburn and is common on Dean’s Wattle Acacia deanei ssp. paucijuga and Wallowa Acacia euthycarpa around Mount Korong.  Images in Figs 1 to 10 were taken near Mt. Korong and Wedderburn by D. Stewart.

The flower structure of Mistletoe is designed to transfer pollen to and from the head of visiting honeyeaters such as New Holland Honeyeaters Fig 3. commonly seen attending the flowers.   Mistletoe Birds follow the fruiting cycle of mistletoe species and consume the fruit.  The digestive system of Mistletoe Birds is modified to facilitate rapid transit of ingested fruit and the bird’s behavior is adapted to increase the chance of seed falling to a suitable growth position on a host plant.   These birds perch atop the host tree and frequently turn parallel to the perch twig prior to voiding the seed which emerges like a necklace of pearls, to slowly drip down through the foliage Fig 4.

Figs 5 to 10 illustrate some of the Lepidoptera dependent on mistletoe as the food plant for their larvae.

Fig 10 is of an Ogyris butterfly whose larvae are dependent on the attendance by certain ant species.  The butterfly has brilliant iridescent metallic blue upper wing surfaces that flash in the sunlight and are hidden from view as the insect keeps wings together when purchased on the mistletoe.

The obvious thought to ponder when considering these examples of interdependent associations is which species is dependent on which other species for ongoing function of this component of the ecosystem?

Article – D. Stewart

Images in Figs 1 to 10 were taken near Mt. Korong and Wedderburn by D. Stewart.