Decoding the Little Fire Ant Invasion and Unique Biology in Israel
An expert from the University of Haifa details the biology, invasive spread, and unique cloning reproduction mechanisms of the little fire ant in Israel.
The world of ants in Israel is rich and diverse, but over the past two decades, a new invasive species has fundamentally altered the ecological balance. The little fire ant (Wasmannia auropunctata) is a painful nuisance for humans and animals alike, as well as a fascinating biological marvel that challenges traditional understandings of natural reproduction. To better understand this tiny invader, we spoke with Dr. Eyal Privman from the Institute of Evolution at the University of Haifa, who researches ant evolution and genetics.
The Arrival and Spread in Israel
When did the little fire ant first appear in Israel, and how did it arrive? "Awareness of the little fire ant's presence in Israel began over 20 years ago, but it is difficult to pinpoint the exact arrival of the first ant, as they are usually only discovered after they have already established and begun spreading," Dr. Privman explains. "We assume they arrived via maritime trade, for example in timber shipments from South America. This is a known global pattern, much like how the red imported fire ant reached the United States over a century ago."
Despite originating in humid tropical environments like the Amazon basin, these ants thrive in Israel's arid climate entirely due to human intervention. "Israel is a dry country where soil is meant to be dry most of the year—conditions that should have prevented their survival," notes Dr. Privman. "The only reason they manage to live here is because of humans. We irrigate fields, lawns, private gardens, and public parks, creating a humid environment for them. Without our artificial irrigation, they simply could not survive here."
Biology and Unique Reproductive Mechanisms
Unlike most ant species that feature a single queen per colony, little fire ant colonies are polygynous, housing multiple queens. This allows them to produce a massive volume of eggs and expand rapidly. Furthermore, colonies spread through budding, where a group of queens and worker ants walk over to establish a nearby nest rather than founding one from scratch. However, human transport remains the primary vector for long-distance dissemination. "The main hotbed is nurseries," says Dr. Privman. "A person buys an infested potted plant with fire ants in the soil, takes it home, plants it in the garden, and suddenly there are fire ants in a new neighborhood."
Perhaps the most astonishing aspect of the little fire ant is its cloning mechanism. While standard sexual reproduction involves a 50-50 split of maternal and paternal genes, little fire ants bypass this entirely for monarchs. Queens clone themselves to produce genetically identical queen offspring. Meanwhile, males are exact genetic clones of their fathers. "The queen mates with a male, but when she lays an egg destined to become a male, her own DNA is entirely excluded from the egg, leaving only the father's DNA," Dr. Privman elucidates. Worker ants are the only ones produced through standard sexual reproduction, but they are sterile and cannot reproduce.
"The most insane finding in the little fire ant is that it clones itself. The queen clones herself so that the daughter queen is a complete genetic copy of her, and the male is a clone of the father, creating separate lineages with no genetic mixing."
The Impact of Climate Change
As a tropical species heavily dependent on humidity and warm temperatures, climate change and global warming threaten to expand their potential living areas. As temperatures rise, regions that were once too cold for them will become viable habitats. Nevertheless, water remains the primary limiting factor in Israel. Without continuous human irrigation, the extreme dryness associated with climate change would naturally curb their expansion.
Concluding his insights, Dr. Privman emphasizes that the greatest ongoing challenge in studying these creatures is deciphering physiological control mechanisms. "For example, we still do not know for certain how the queen 'decides' or controls the identity of the egg—whether it will develop into a cloned male, a cloned queen, or a sterile worker."
