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Published on: December 19, 2013
Sublethal effects of invasive fire ant venom on a native lizard
Katherine E Boronow1, Tracy Langkilde
1Department of Ecology and Evolutionary Biology, Yale University, New Haven, Connecticut, USA. katherine.boronow@aya.yale.edu
Summary
Invasive fire ant venom does not appear to harm eastern fence lizards, even after generations of exposure. Lizards likely survive by changing their behavior and physical traits, not by evolving venom resistance.
Area of Science:
- Ecology
- Evolutionary Biology
- Toxicology
Background:
- Invasive species introduce new selective pressures, like toxins, to native ecosystems.
- Native species may adapt by developing toxin avoidance or tolerance.
- Red imported fire ants (Solenopsis invicta) possess an alkaloid-based venom.
Purpose of the Study:
- To assess sublethal effects of invasive fire ant venom on the eastern fence lizard (Sceloporus undulatus).
- To investigate if long-term exposure (approx. 35 generations) confers physiological resistance in lizard populations.
Main Methods:
- Lizards were naturally exposed to fire ant stings to measure impacts on bite force, righting ability, and sprint speed.
- Blood hemolysis induced by venom was quantified.
- Performance and hemolysis were compared between lizard populations with varying fire ant invasion histories.
Main Results:
- Fire ant venom did not exhibit dosage-dependent sublethal effects on lizard performance.
- No evidence of evolved physiological resistance was found; impact on performance and hemolysis was similar in naïve and experienced lizard populations.
- Venom exposure did not significantly affect lizard performance metrics or hemolysis levels.
Conclusions:
- Eastern fence lizards do not appear to have evolved physiological resistance to fire ant venom.
- Lizards may survive fire ant invasions through adaptive behavioral and morphological changes rather than direct venom tolerance.
- Further research into behavioral and morphological adaptations is warranted.
