Fire ant baits are considered safe for humans and most animals. The bait used to treat fire ants is specifically targeted to kill ants.
Fire ant bait products do not just target fire ants. Broadcast baiting can also affect other ant species. These effects are not large-scale or long-term.
Fire ants have a far greater negative impact on native ants than any effects caused by eradication treatment.
We do regular trials with all products we intend to use for treatment. When we identify a product that fits into a low-risk profile, we trial it in the field to check how it compares with the products we currently use. Key details we are looking for during these trials include:
- how effective the products are at destroying fire ant colonies
- what treatment regimen provides optimal results
- impacts on non-target organisms (including native ants)
- how they compare with the methods we currently use.
We also assess how likely the active ingredient could be a risk to the environment. We aim to use products with the lowest risk profile and environmental impact that also provide the highest level of treatment success that we need to achieve eradication.
Study: Local ant populations after baiting in Brisbane, Australia
Our scientists collected data from 60 sites that were infested with fire ants and treated between 2001 and 2006. They found that most local ant species either increased in number or recorded no change (McNaught et al. 2014). This suggests that local ants were not affected by repeated applications of broadcast bait.
In addition to fire ants, ants in the genus Pheidole, which include the introduced coastal brown ant, Pheidole megacephala, also reduced in number. The baits we use are registered to treat this species, so this trend was not surprising.
Native black ants and meat ants (Iridomyrmex species) increased their numbers rapidly after fire ants were killed on these sites, meaning that the presence of fire ants negatively impacts their numbers. Black ants and meat ants are ecologically important ant species that often dominate native ant communities. Their low numbers in the data were caused by the presence of fire ants rather than the baiting.
If native ants took the bait and became affected to the point of killing their queen and the nest, then rapid re-colonisation would occur from outside the treated area.
The presence of fire ants and their potentially devastating ecological impacts far outweigh the impacts on native ants than those caused by our baiting activities.