Saturday, 1 March 2008

A prickly customer

It can be a bit of a pain to walk through the bush when the undergrowth is thick. Even more so when there is Bursaria Bursaria spinosa present.
This shrub has thorns, hence the species name, spinosa. But the genus name Bursaria comes from the shape of the seed capsules - they're shaped like little purses and quite beautiful at each stage of their development.
Bursaria is also called Sweet Bursaria, because of the fragrent flowers that appear in spring and summer. It's a very common plant, but as is often the case, its beauty can often be overlooked because it is common. But it is interesting that scientists have found that the Bursaria has a relationship butterflies and ants - certain species of butterflies feed on the plant, the larvae graze on the plant and a certain ant species protects the caterpillar from predation and hosts the pupae within their nest. The Eltham Copper Butterfly is one of those. This is what the Department of Sustainability and Environmant (DSE) has to say on their webpage:
The Eltham Copper Butterfly prefers woodland habitat with an understorey containing the shrub Sweet Bursaria and a ground layer of native grasses, mosses and leaf litter. Female adults lay eggs during summer on the shoots and stems of Sweet Bursaria (Bursaria spinosa), and sometimes in the leaf litter close to the base of the plants. The larvae hatch after about 10 to 14 days and shelter and develop in the ant's nest located around the plant roots. Larvae are nocturnal, sheltering in the nest during the day and emerging at night to feed on the Bursaria leaves, where they are constantly attended by the ants. In return for this protection and care, the ants feed on secretions of sugar and amino acids from the larvae. This may keep the larvae free from fungal and bacterial disease. Adult butterflies emerge between late November and January. They feed on the nectar produced by the flowers of small and larger Sweet Bursaria plants, and sometimes on nectar of other plants such as Hakea and Cassinia species.

Bursaria spinosa

Bursaria spinosa flowers

Bursaria spinosa seed capsules

Bursaria spinosa seed capsules

1 comment:

Duncan said...

Love the bursaria Boobook, have planted a lot in our reserves, and have had one in the garden for over 30 years. The form down on the coast grows into quite a sizable tree.