Project Title
The Argentine ant (Linepithema humile) in Victoria and across southern Australia - tracking an invasive species
Abstract
Recent research on the Argentine ant (
Linepithema humile) in southern Europe and the Americas has revealed supercolonies that have striking differences in colony structure from what is seen in its native range, Argentina. Genetic changes have been associated with a shift in colony structure from multicoloniality (intra-specific aggression between all colonies) to unicoloniality (absence of intra-specific aggression between colonies). The absence of aggression and territorality contribute to numerical and ecological dominance and lead to successful invasions, with the resultant unicolonial supercolonies in some cases extending over thousands of kilometres. The Argentine ant has also invaded widely in southern Australia. I am investigating the genetic structure and behavioural variation of
L.
humile populations in Victoria and across Australia to elucidate their invasiveness and impacts on this continent.
In my Honours study, which used four polymorphic microsatellite markers and intra-specific behavioural assays, I reported the presence of supercolony structure in 17 L.
humile nests across Greater Melbourne. Genetic diversity was reduced relative to that reported in the native range and there was no genetic or behavioural heterogeneity. However, a small pilot study of L.
humile nests across southern Australia showed genetic heterogeneity with distance, suggesting independent introduction in the other states.
To provide more detailed insight into the population structure across southern Australia, I am now increasing the numbers of sampling locations and microsatellite markers and doing more extensive behavioural assays. Screening of microsatellite genotypes of
L.
humile from five diverse international locations is also being carried out to determine if a source region for the invasion(s) is suggested. I am co-supervised by Dr. Alan Yen from DPI Knoxfield and am affiliated with both the Centre of Environmental Stress and Adaptation Research (CESAR) and the Australian Centre for Biodiversity Analysis, Policy and Management (ACB).
See also
Centre of Environmental Stress and Adaptation Research
