Blue Tigers hit the air
THE Blue Tiger butterfly is not one of the most common in the region. In many years only a few are seen around, but every now and then there is an increase in numbers.
Local variations in numbers are most likely due to growing conditions for the preferred host plants for the larvae.
The preferred host plant is the Corky Milk Vine that grows in scrub areas.
Under natural conditions most of our scrub plant species grow depending on climatic conditions and vines may not produce enough suitable leaves for butterfly larvae each year.
Also feeding in the same area is the Common Crow or Oleander butterfly.
Both these butterflies use the Corky Milky Vine as food for larvae as the vine has a milky sap that contains alkaloids to which the larvae are immune.
Corky Milky Vine (Secamone elliptica) has small opposite leaves, 1 to 5cm long and a corky fissured bark that thickens as the vine matures.
Flowers are a fairly nondescript pale yellow and fruit is a long thin pod that opens to produce a large number of seeds, each with a silky tuft of hairs that enable the seeds to use wind drift for dispersal.
An old vine can have 50mm stems and cover whole trees.