Bursaria Spinosa - Ecology

Ecology

Living for 25 to 60 years, Bursaria spinosa can resprout from its woody base after bushfire. Highly rhizomatous, plants of a stand are often genetically a single plant. Despite being genetically identical, different plants and even single shoots can be very distinct in appearance (for instance, spineless shoots previously regarded as a subspecies "inermis"). Its seed is wind-dispersed and it is a colonising plant.

A wide variety of insects visit the flowers of Bursaria spinosa, the most important pollinators of which appear to be beetles of several families. Common visitors recorded from field work around Armidale were jewel beetle species such as Curis splendens and Stigmodera inflata, longicorn beetles including Amphirhoe sloanei and Tropocalymma dimidiatum, scarab beetles and tumbling flower beetles. Beetles and scoliid wasps all carried significant amounts of pollen. Other visitors such as flies and butterflies carried much lower amounts. The larvae of the jewel beetle species Astraeus crassus live in tunnels in dead and dying branches. Caterpillars which feed on Bursaria spinosa include Proselena annosana, two-ribbed arctiid (Palaeosia bicosta) and bark looper moth (Ectropis subtinctaria), while those of the clouded footman (Anestia ombrophanes ) graze on algae and lichens which grow on the branches.

The Bright Copper (Paralucia aurifera) and ant species Anonychomyrma nitidiceps form a complex symbiotic relationship on Bursaria spinosa. Butterflies lay their eggs on the underside of the leaves, and the caterpillars feed on the leaves before pupating in the soil at the foot of the plant. The ants excavate chambers in the soil where the caterpillars sleep and later pupate, and accompany the caterpillars when the latter are feeding. They are thought to feed on the caterpillars' secretions. Caterpillars of the Fiery Copper (Paralucia pyrodiscus) are likewise accompanied by ants of the genus Notoncus, and the third species, the endangered Bathurst Copper (Paralucia spinifera), also breeds and feeds exclusively on the subspecies lasiophylla in Central New South Wales.

Cattle and rabbits graze on young plants..