POPULATION DEMOGRAPHY OF AUSTRALIAN FERAL BEES (APIS-MELLIFERA)

Honey-bees are widespread as feral animals in Australia. Their impact on Australian ecosystems is difficult to assess, but may include compe tition with native fauna for floral resources or nesting sites, or ina dequate or inappropriate pollination of native flora. Tn this 3-year s tudy we examined the demography of the feral bee population in the rip arian woodland of Wyperfeld National Park in north-west Victoria. The population is very large but varied considerably in size (50-150 colon ies/km(2)) during the study period (1992-1995). The expected colony li fespan for an established colony is 6.6 years, that for a founder colo ny (new swarm), 2.7 years. The population is expected to be stable if each colony produces 0.75 swarms per year, which is less than the numb er predicted on the basis of other studies (2-3 swarms/colony per year ). Therefore, the population has considerable capacity for increase. M ost colony deaths occurred in the summer, possibly due to high tempera tures and lack of water. Colonies showed considerable spatial aggregat ion, agreeing with earlier findings. When all colonies were eradicated from two 5-ha sites; the average rate of re-occupation was 15 colonie s/km(2) per year. Ten swarms of commercial origin were released and we re found to have similar survival rates to founder colonies. However, the feral population is self-sustaining, and does not require immigrat ion from the domestic population.