Tiny South American Fire Ant Poses Significant Threat in Israel
A small invasive fire ant species, believed to have arrived in Israel from South America via maritime trade over 20 years ago, has become a significant nuisance and biological puzzle. Dr. Eyal Priechman from the University of Haifa's Evolution Institute explains that while the ant's presence was first noted two decades ago, its exact arrival date is unknown due to its ability to establish and spread before detection. The ant's painful sting, caused by venom injected through a stinger at the tip of its abdomen, is a primary concern for humans and animals, though it is not typically life-threatening in Israel, unlike its larger counterpart.
Despite originating from humid, tropical regions, the small fire ant thrives in Israel's drier climate primarily due to human irrigation of fields, lawns, and gardens, which creates the necessary moist environment. This reliance on human activity highlights how human behavior facilitates the spread and survival of invasive species. The ants' ability to adapt and thrive is further amplified by their unique reproductive strategy.
Unlike most ant species with a single queen, small fire ant colonies can host numerous queens, enabling rapid reproduction and egg-laying. Queens and workers can also split from existing colonies to form new ones nearby. Human activity, particularly the purchase and transport of infested plants from nurseries, is the main driver of their long-distance spread across new neighborhoods. Climate change may also expand their potential habitat as global temperatures rise, though water availability remains a key limiting factor in Israel.
Perhaps the most astonishing aspect of the small fire ant is its reproductive mechanism, which involves cloning. A queen produces a genetically identical daughter queen. Remarkably, male ants are clones of their fathers, with the queen's DNA being excluded from the egg. Worker ants are the only ones produced through sexual reproduction but are sterile. Researchers are still working to understand the physiological mechanisms behind these complex reproductive processes, particularly how queens determine the sex and reproductive potential of their offspring.
