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Invasion of the Clone Fireports

The fire ant can reproduce both sexually and asexually. The worker ants, which are all female, are the result of the normal mating process between a female and a male, but each time the queen wants to create another queen, she chooses to reproduce without a male, asexual reproduction or cloning

The fire ant colony demonstrates teamwork. Illustration: depositphotos.com
The fire ant colony demonstrates teamwork. Illustration: depositphotos.com

The exit from the second quarantine of the Corona brought many Israelis back to the public gardens and parks. There, they encountered a different kind of blow, much less lethal, but very stinging: the fire ports taking over many open spaces throughout the country.

the little fire ant (Wasmannia auropunctata) was first observed in Israel in 2005 and since then it has spread in large parts throughout Israel and is now a nuisance to humans, but they are not the only ones who suffer from it. The fire ant also greatly affects the local biodiversity. Its spread became so problematic that the Ministry of Environmental Protection decided to take new steps to stop it.

fire ant Small and dominant. Photo: ezzillo

From Africa or Brazil?

"No one knows when the invasion of fire ants really began in Israel" says Prof. Avraham Hefetz, a chemical ecologist and evolutionary biologist at the George S. Wise at Tel Aviv University. "We discovered the ant for the first time in 2005 when one of my students, who was studying the impact of invasive ants, found a species she didn't know during one of her collection trips in the Kinneret."

At the time, Hefetz assumed that the ant came to Israel from West Africa, but collaboration with a French team of scientists who studied the fire ant in different parts of the world determined that the ant actually came to Israel from Brazil.

"It is not clear how the ant got here from Brazil, but there is a good chance that it was young Israeli backpackers who brought it when they returned to Israel. Since Brazil and South America are popular destinations among young people who have finished their military service, the likelihood that this is how the ant got here is very real."

A comprehensive study published in 2014  by researchers from France thoroughly examined the effect of climate change on the distribution of invasive species of ants around the world. The study examined the The impact of the climate crisis on the distribution of 15 invasive species of ants, including the red fire ant. The researchers examined how these changing conditions will affect the spread potential of the ants throughout the world (except Antarctica) as well as in a targeted manner in sensitive areas (hotspots) where there is a large variety of rare and particularly vulnerable animals and plants. Unfortunately, the fire ant is one of the five ant species that will benefit from climate change, and by and large: its distribution rate is expected to increase on all continents, especially in the southwestern United States, North Africa and Southern Europe, India and the Arabian Peninsula, South Africa and Australia.

Clones of the parents

After the discovery of the fire ant in Israel, the researchers collected eggs from different nests and conducted a molecular study, analyzing the DNA composition of the ants. According to Hefetz, the research findings indicated that all the queens, who came from different nests, are actually clones of each other. "The fire ant has a very strange reproductive system," says Hefetz. "Each queen is a clone of her mother, while each male is a clone of his father."

"The fire ant can reproduce both sexually and asexually (al-zivgit, DD)," explains Dr. Eyal Pribman, a social insect genomics researcher at the Institute of Evolution at the University of Haifa, about the fire ant's reproduction process, which sounds like a plot For a creepy science fiction movie. "The worker ants, which are all female, are the result of the normal mating process between a female and a male, but every time the queen wants to create another queen, she chooses to reproduce without a male, in asexual reproduction. That is, it replicates itself. Therefore, every new queen that is created in Israel is an exact genetic copy of the first queen fire ant that accidentally arrived in Israel 20 years ago."

The movie doesn't end there. According to Pribman, worker ants are created as mentioned by sexual reproduction (meaning they have ancestors), but in fact, they themselves never reproduce. This means that the most essential aspect of evolution - the transfer of genes to the next generation - is lost. If so, the question is required: how does the fire ant produce male ants. "It's really getting crazy here," says Pribman. "Every male ant is a clone of the father, but since males are unable to lay eggs and reproduce themselves, they need a queen to do it for them. Thus, each male egg that the queen lays is actually a genetic copy of the father only, without any genetic male for the queen herself. In fact, the queen only facilitates the cloning process of the males. This strange reproductive mechanism developed only in ants."

In addition, Pribman explains that the developed and advanced social structure of the fire ant may be the root of the problem with the invasiveness that characterizes the small insect.

"In a typical colony of ants there is one queen who is the mother of all the workers. This is not the case with the fire ant. Each nest of fire ants is inhabited by multiple queens, as well as workers who are not the offspring of that queen. Despite this, they function as a community and cooperate instead of fighting each other. This is a dramatic difference and may be the one that allows this species to spread so quickly," Pribman emphasizes.

Citizens report ants

According to Hefetz, experts agree that in Israel, the fire ant spreads mainly through Pots that come from nurseries, a hypothesis that was strengthened in the last year after data collection by the Ministry of Environmental Protection.

"Since the beginning of the year, we have inspected almost 100 public and private nurseries throughout Israel and discovered that fire ants are present in most of them," says Dr. Gal Zagron, head of the Pest and Pest Control Division at the Ministry of Environmental Protection. According to her, the division placed dealing with the fire ant at the top of the agenda and to that end they established three focus groups dedicated exclusively to dealing with the pest.

"The first team is an audit committee responsible for providing a complete picture of the state of proliferation; The second group deals with citizen science and ways to create involvement in the local and regional councils, while the third group was tasked with developing a protocol for best practices to control the spread of the fire ant," explains Zagron. In order to meet their goals, the Ministry of Environmental Protection cooperates with the Nature and Parks Authority, with the Entomological Laboratory for Applied Ecology of the Steinhardt Museum of Nature and with the Society for the Protection of Nature.

"Together with the Society for the Protection of Nature, we created civil surveys designed to involve the public in the fight against the fire ant. This is a very simple form that anyone who sees an ant nest can fill out online And the observations appear on a map that is open to the public and that anyone can see. Of course we have to confirm these observations, but it is very helpful for the work we do," says Zagron.

One of the reasons that the Ministry of Environmental Protection is interested in sharing the efforts with the public in this matter is to receive information about new sightings in centers that do not have a known history of the spread of the fire ant, and thus reach and treat them as early as possible. "The newer the spread, the easier we can get rid of it," says Zagron.

Focus on local councils

This year, after discovering that the main sources of the spread of fire ants are private and public nurseries, the Ministry of Environmental Protection began to closely examine the local councils, in order to better understand the path of spread.

"We checked all the local councils and realized that in the councils there is a separation between the officials who are responsible for gardening in the public and open areas and the officials who are responsible for handling and controlling dangerous substances and pesticides and many times there is no communication between them. This means that on the one hand the gardeners unintentionally spread the ants from the nurseries in public spaces without being aware of it and on the other hand the exterminators from the hazardous materials division spray the insecticides after they receive complaints from citizens who are bitten by the ants. Understanding this problem was a big breakthrough for us this year," explains Zagron.

The main sources of fire ant infestation are private and public nurseries. Photo: christin noelle – unsplash

According to her, it is not always easy to find all the nurseries. In many cases they are used only by local councils and are not known to the public and are therefore not registered as businesses. Even municipalities that do not have their own nurseries probably contribute to the spread of the ants because they buy from other large nurseries.

"Because of this situation, in the next step we will contact all the local councils, whether they have their own nurseries or not, and we will help them deal with the problem in their jurisdiction," says Zagron.

However, one of the main problems in the fight against the fire ant in the nurseries is the location of the bait that contains the insecticide - it must be placed in a dry place, but nurseries usually have a very high humidity level. "The insecticide is concentrated in small grains that are spread by exterminators at different points of the nursery. The ants carry the grains into the nest and there the substance kills the entire colony, but if the grains absorb a lot of moisture they become too heavy for the ants to be able to carry them and then they don't bring them into the nest," explains Zagron. "If you just spray the place with a pesticide, the ant population recovers quickly and goes back to thriving - because we didn't actually destroy the nest itself."

Delayed Reaction

"This year a lot of work was done on the subject of the fire ant," Zagron adds. "Not only did we update the guidelines in order to get the local authorities to step up and deal with the problem in their nurseries, but we also located many infected areas and we are developing methods to deal with the fire ant. In addition, because the expansion is on such a large scale, we also plan to expand the activity to public areas in cooperation with the local authorities."

"Unfortunately, we didn't react quickly enough in the past so the spread has probably reached too large a scale to stop it completely, but we haven't lost hope. We are sure that with the right steps and with the continuous effort of the Ministry of Environmental Protection, the local authorities and all the other organizations involved, it will be possible to control and even curb the spread of the fire ant", concludes Zagron.

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