Scientists create world’s first mutant ants with gene editing technology

Ants use porous hairs on their antennae to detect pheromones. Scientists developed mutant ants lacking this ability. (Credit: Sean K. McKenzie/The Rockefeller University)

It may sound like a script for a science fiction movie, but scientists have created the world’s first mutant ants.

Two independent research teams have harnessed the gene editing technology CRISPR to genetically alter the ants. In one study, researchers at Rockefeller University modified a gene essential for sensing the pheromones that ants use to communicate. Experts say that the resulting deficiencies in the ants’ social behaviors and their ability to survive in a colony, sheds light on social evolution.

“It was well known that ant language is produced through pheromones, but now we understand a lot more about how pheromones are perceived,” said Daniel Kronauer, head of Rockefeller University’s Laboratory of Social Evolution and Behavior, in a statement. “The way ants interact is fundamentally different from how solitary organisms interact, and with these findings we know a bit more about the genetic evolution that enabled ants to create structured societies.”
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CRISPR, which has been compared to a pair of “molecular scissors,” lets scientists alter or replace specific sections of DNA.

Scientists used CRISPR to disrupt a gene known as Orco in the clonal raider ant, species Ooceraea biroi, but then faced the challenge of keeping the mutant ants alive. “We had to convince the colonies to accept the mutants. If the conditions weren’t right, the worker ants would stop caring for larvae and destroy them,” said Rockefeller University graduate fellow Waring Trible, in the statement. “Once the ants successfully made it to the adult phase, we noticed a shift in their behavior almost immediately.”

While ants typically travel single file, researchers noticed that the mutant ants couldn’t fall in line, along with other behavioral abnormalities.

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The results of the study are published in the journal Cell.

This image shows a Harpegnathos saltator worker ant in the process of stinging a cricket to paralyze it and drag it into the nest as part of its hunting duties. (Credit: Brigitte Baella)

A separate study, also published in the journal Cell, saw scientists target the Orco gene in the Indian jumping ant, Harpegnathos saltator. Experts note that the Indian jumping ant is unlike other ant species because only the queen can mate and pass genes onto the next generation. However, any adult female worker of the species can become a “pseudo queen” in the queen’s absence.

The second study was led by researchers from New York University, NYU School of Medicine, Arizona State University, the University of Pennsylvania and Vanderbilt University.

Ant queens suppress the ability of female workers to mate and lay eggs, although if the queen is removed, the most aggressive females, after winning a series of antenna duels with rivals, can go on to lay eggs.

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The study engineered three mutant ants to lack the Orco gene. Without the gene, females cannot process pheromones, making them less likely to engage in dueling.

“While ant behavior does not directly extend to humans, we believe that this work promises to advance our understanding of social communication, with the potential to shape the design of future research into disorders like schizophrenia, depression or autism that interfere with it,” said Claude Desplan, professor at NYU’s Department of Biology, and one of the report’s authors, in a statement.

In a third related study by the University of Pennsylvania, scientists injected the brain chemical corazonin into ants transitioning to become a pseudo-queen, which simulated worker-like hunting behaviors, while inhibiting ‘pseudo-queen’ behavior, such as dueling and laying eggs.

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These results are also published in the journal Cell.

Gene editing has been generating plenty of buzz recently. Earlier this week, scientists announced the elimination of viruses in pigs that could be harmful to people, utilizing the CRISPR technology. The discovery could potentially lay the foundations for pig-to-human organ transplants.

GENE EDITING BREAKTHROUGH COULD PAVE WAY FOR PIG-TO-HUMAN ORGAN TRANSPLANTS

In another project, researchers used gene-editing to correct a disease-causing gene mutation in human embryos, preventing the mutation from passing to future generations. In the stunning discovery, a research team led by Oregon Health and Science University reported that embryos can fix themselves if scientists jump-start the process early enough.

How to Get Rid of Ants Naturally

Ants, ants, ants, everywhere! Those pesky insects have a way of finding every little crack and opening right into your home. With Spring finally in full swing I have begun to see an ant scout here and there and I want to nip it in the bud before they take over my life!

With kids and pets spending the majority of their day playing, crawling, and somersaulting (well the kids are somersaulting, not the dog) across the floor, I am not about to sprinkle a pesticide around my home that will put them in danger.

But the ants…

Thankfully there are plenty of ways to get rid of ants without putting your family at risk. I have talked before about natural pest control but today I am going to focus specifically on getting rid of ants.

How Do Ants Find Food?

Ant colonies will send out scouts to locate food sources. Those little bugs will zig and zag and probe their way until they find food, which they will bring back to their colony, leaving a trail of pheromones behind them. Other ants will follow the trail leaving their own pheromones making the trail stronger until all the little foragers are marching along, back and forth, taking all your goodies back to their home.

Fascinating and annoying all at once.

How to Get Rid of Ants (Naturally, of Course!)

So what is the answer to naturally get rid of ants? There are several approaches you can take. Repel them from coming into your home in the first place, control and eradicate them once they are in, and finally, kill them at their source.

Repel, Repel, Repel

The first step to get rid of ants is to make sure any sweet ingredients in your home are sealed tightly. Clean up the dribbles down the side of the honey jar and make sure your maple syrup lid is on tight. It is also recommended to keep floors swept and all counters free of any food or drips, but that is not usually practical or possible in a busy home like mine. Just do the best you can with this one.

Here are some more ideas to prevent ants from coming into your home:

Create a barrier – Many people have good luck creating a barrier of something ants generally don’t like or won’t cross. Some examples would be drawing a chalk line or sprinkling cinnamon, cayenne pepper, baby powder, or coffee grounds along common entry points.
Citrus Peels – Ants are also repelled by citrus. Oranges, lemons, grapefruits, etc. contain D-limonene and it is effective at killing ants. Save your orange or lemon peels and dry them out. Pulse them in a blender or food processor to make a powder and sprinkle this along entry points in your home. You can also sprinkle these around your garden.
Essential Oils – I have had good results deterring ants that were determined to come in under my screen door with an essential oil spray. Fill a small spray bottle with water and add about 20 drops of peppermint oil. Shake well and spray along doorways and window sills. It repels the ants and covers the scent of any food and pheromones. You can also put several drops of peppermint, orange, or lemon oil on a cotton ball and place it in cabinets to deter ants from snooping around in search of food.
Vinegar – Spraying vinegar along doorways and window sills is another option. This has the same effect as the peppermint oil spray. Mix vinegar 50/50 with water in a spray bottle. Add peppermint oil or a citrus oil like orange or lemon to this mixture to make it even more effective.
What if Ants Are Already In Your Home?

The ants are already in. Now what?

First, find out where they are coming in from and where they are going so that you can figure out the best way to tackle their removal. Something attracted them and that will need to be cleaned up. Then find their entry point so that you can use one of the tips from above.
Once you have found point A and point B, move on to clean up. You will obviously need to remove the ants from your counter, floor, cabinet or wherever they are. You can wipe them up with a cloth (or paper towel if you don’t want to try to remove them from your cloth).
Now on to the important part. You have to remove the pheromone trail. You can use soapy water, a 50/50 water and vinegar mix, or the essential oil spray. If you don’t clean up the trail, other ants will be able to easily find the same food source.
Kill the Ants

I don’t know about you, but my first instinct is to kill any bugs I see in my house (or call for my adventurous daughter to do it for me). However, this may not always be the most effective way to rid your home of ants in the long term.

If you can resist the temptation to kill them immediately, you can make an ant poison they will take back to their colony and feed to all of their friends. It requires a little bit of patience but will pay off in the end.

Option 1: Borax

I learned this trick from Katie of Kitchen Stewardship on a podcast episode. It does not immediately remove the ants from your kitchen (in fact it may seem like it attracts more at first, which is actually a good thing) but it works really well for the long term because it works to eliminate the colony and not just the ants entering your home.

She recommends mixing equal parts Borax (I use this one) and corn syrup and spreading it on an index card. The ants are attracted to the corn syrup and carry it back to their nest. All the ants that feed on the corn syrup mixture will be killed by the Borax. (I cover the safety of using Borax here.)

Option 2: Baking Soda

If you are uncomfortable with using Borax, you can try using baking soda. Mix equal parts baking soda and powdered sugar and place it in a lid near where you think the ants are coming in. The powdered sugar will attract them, but since they are unable to differentiate between the sugar and the baking soda, they will carry both back to their nest.

When ants consume baking soda it reacts with the acidic substance in their bodies and is fatal to them. Again, not an immediate fix, but very beneficial in the long term.

Other Ant Killing Tips to Try

Diatomaceous earth (use food grade only) is highly effective at getting rid of ants and other pests that crawl, rather than fly. DE is a fine powder made from the fossilized remains of diatoms, a type of algae. Because it is so fine, it is perfectly safe for humans and animals and is actually beneficial to consume. (It is good for hair and nails, among other things.)

Ants, however, become dehydrated when they come into contact with DE because it damages their waxy coating which will kill them. They will not take it back to their colony but it will stop them from making any progress into your home.

Sprinkle DE along doorways and window sills, and any other points of entry, in trash cans, and along cabinets and baseboards. I have also sprinkled it liberally on my carpet during a particularly bad ant invasion. After a few days the ants were gone and I just vacuumed up the DE.

Use extreme care if you will be using this outside and avoid any areas that may have honey bees. The DE will stick to their legs and they will consume it when they are grooming. DE is sharp to small insects and will kill them. We want to kill the ants and fleas, but NOT the honey bees!

Castille soap will also compromise the waxy coating that protects the ants. Make a spray with 1 quart water and 1/4 cup liquid castile soap. Spray along doorways and window sills and anywhere else you see ants coming in. Repeat a couple of times a day until the problem is resolved.

Dealing With More Than Ants?

If you have other pests plaguing you there are other natural pest control options for your home and some organic ideas for your garden.

Real Food & Killing Ants Naturally

I had so much fun on this interview with Katie Kimball of KitchenStewardship.com. She is a fantastic writer and researcher, pregnant with her fourth child, and manages a household and her popular blog (and makes it all look easy). We recorded at 9 PM after our collective 8.5 children were sleeping and she provided a lot of great tips for cooking real food for a family. My apologies in advance for the little bit of audio feedback in this episode. The problem has been fixed for the future episodes.

Katie shared some of her best tips for getting rid of pests like ants and wasps naturally without chemicals that can harm your children.

Other Fun Topics We Talked About

0:30- Random brain facts like why you can’t tickle yourself
1:40- Katie’s ten foundational habits for a healthier family
2:00- The struggle to balance it all
2:20- Katie’s “Core Four” = Environment, Nutrition, Time and Budget
3:00- One thing at a time approach- Monday missions
3:40- One simple switch that makes a big difference
4:15- Katie’s three budget friendly real foods that she makes daily
5:00- The super inexpensive way her family gets probiotics
6:15- 3 foods that seem scary but aren’t
8:00- The simple way to make homemade yogurt
11:00- Real food really does cost more
11:45- How to stretch an organic chicken and make multiple batches of broth
15:35- How to prepare beans if you are going to eat them
18:45- A tip to fix crunchy beans
20:20- Her quick and easy natural way to get rid of sugar ants
22:20- Lines that insects can’t cross
22:38- Katie’s natural tip to get rid of wasps
23:53- The biggest struggle Katie thinks the next generation will face
24:30- Battling the sugar giant
26:50- My battle cry
27:30- The advice she wishes she’d gotten earlier in life
29:20- Easy action steps to take right now
31:11- The two books she can’t live without

Resources Mentioned

  • Katie’s start here page with her foundational habits
  • Homemade yogurt recipe
  • Natural tips for killing ants naturally
  • Natural ways to deal with wasps
  • How to cook dried beans
  • Book: Crock On
  • Website: Gnowfglins.com
  • Katie’s Kindle Books on Amazon

Mutant Ants Provide Insights Into Social Interaction

Ants genetically engineered to lack their “sense of smell” became unable to communicate, forage or compete to be a queen, as their antennae and brain circuits failed to fully develop. For the first time, researchers successfully shut down a crucial portion of the ant’s olfactory system by using the CRISPR-Cas9 technology.

This finding, stemming from a recent study conducted by Arizona State University scientists and their colleagues from New York University, University of Pennsylvania and Vanderbilt University, was published online today in the journal Cell.

“While ant behavior does not directly extend to humans, we believe that this work promises to advance our understanding of social communication, with the potential to shape the design of future research into disorders like schizophrenia, depression or autism that interfere with it,” said corresponding author Claude Desplan, professor at New York University’s Department of Biology.

“We found that a species of ant may be the first model to enable in-depth functional analysis of genes that regulate social interaction in a complex society,” said study co-author Danny Reinberg, a professor with the NYU School of Medicine and investigator for the Howard Hughes Medical Institute.

Jürgen Liebig, an associate professor with ASU’s School of Life Sciences and expert in social insect societies, is also encouraged by the results.

“Having studied the behavioral plasticity, colony organization and chemical communication of the ant Harpegnathos saltator for more than two decades, I am happy to see that this charismatic species is finally maturing into a genetic model,” co-author Liebig said.

Smell talk

The current results are based on the fact that ants communicate through pheromones, secreted chemicals that trigger responses. Such odors are used to spread alarm as a predator approaches, leave a trail to food, indicate social (caste) status and signal readiness to mate, all within cooperative societies that achieve complex tasks. Ants can receive such signals because they have proteins called odorant receptors on their antennae, with each protein the right shape to bind to a specific odorant chemical.

For any odor or pheromone to be processed in an ant’s brain, however, past studies had shown that both the right odorant receptor protein and a shared, common partner protein called Orco must be present. The current team successfully engineered the genetic loss of Orco protein, which resulted in ants that could no longer perform some, if not all, pheromone-based social interactions.

Specifically, the altered young ants, unlike their nestmates without the changes, spent much of their time wandering out of the nest. They failed to interact with other members of the colony and were unable to forage and bring food back to the nest. Furthermore, mutant females no longer groomed males, a pre-mating behavior.

The current study focused on the Indian jumping ant, Harpegnathos saltator, which is unlike many ant species in which only the queen can mate and pass on genes to the next generation. Any Harpegnathos female adult worker can be converted into a queen-like state in the absence of the queen or other queen-like workers.

This is because the queen secretes a pheromone that suppresses the ability of workers to mate and lay eggs. If the queen is removed, the most aggressive females, after winning a series of antenna duels, undergo this transition, and can go on to produce progeny, which is essential for colony survival.

The current study found that, without Orco, the females cannot process pheromones, which makes them much less likely to engage in dueling.

“This ant system allows dissecting the organization of a society in which social interactions of all individually marked colony members can be tracked easily,” Liebig added.

Another study result proceeded from the fact that each neuronal cell (odorant receptor neuron) capable of processing the presence of a given pheromone on the surface of an ant’s antennae sends out extensions that converge in a specific blob-like brain structure called a glomerulus. Information about that odor is processed there.

Past studies have suggested that, in solitary insects like mosquitoes, fruit flies and moths, the connections between odorant receptors and glomeruli are “hard-wired,” i.e. their neural development is independent of receptor activity. To the contrary, mammals appear to have odorant receptor cells with extensions capable of homing in on the correct glomeruli based on which odorant receptors they express. This makes the function activity-dependent in mice (and humans), in contrast to the hard-wired context of flies, say the study authors.

The new research suggests that Harpegnathos ants may also have evolved to have flexible, activity-based patterning of nerve connections, which has led to their expanded repertoire of olfactory receptors for detecting pheromones. This flexibility is required for communication based on the pheromone sensitivity and resultant activity of their olfactory neurons, say the authors. Accordingly, the loss of the Orco gene left female ants, on average, with just 62 of the 275 glomeruli that they would normally develop to process pheromone sensing.

Using Seaweed To Kill Invasive Ants

Scientists at the University of California, Riverside have developed an inexpensive, biodegradable, seaweed-based ant bait that can help homeowners and farmers control invasive Argentine ant populations.

The researchers found the “hydrogel” baits, which look like liquid gel pills but have a jello-like consistency, reduced ant populations 40 to 68 percent after four weeks. After a second treatment, between weeks four and five, ant population reductions were maintained at 61 to 79 percent until the experiment ended after eight weeks.

“A 70 percent reduction is really successful, especially considering we are not spraying an insecticide but instead using a very targeted method that is better for the environment,” said Dong-Hwan Choe, an assistant professor of entomology at UC Riverside and an assistant cooperative extension specialist. “With 70 percent control, homeowners really don’t see any ants.”

Jia-Wei Tay, a post-doctoral scholar in Choe’s lab, is the lead author of the paper. Co-authors are Choe; Mark Hoddle, an entomologist at UC Riverside; and Ashok Mulchandani, a distinguished professor of chemical and environmental engineering.

In addition to the applications for homeowners in an urban environment, which was the focus of this paper, the hydrogels have applications in agriculture, including in citrus groves and grape vineyards.

For example, the Asian citrus psyllid has decimated citrus trees in Asia, South America, Florida and now threatens California’s citrus industry. To combat the bug in California, Hoddle coordinated the release of wasps that are native to Pakistan and a natural enemy of the Asian citrus psyllid. Unexpectedly, Hoddle found Argentine ants were killing the wasps.

This summer, the team will coordinate research in citrus groves in southern California. The team wants to measure the effectiveness of hydrogels in controlling Argentine ant populations. If the hydrogel baits can control the ants, the wasps can do their job protecting citrus trees from Asian citrus psyllid, which transmit Huanglongbing, a bacterial disease that kills citrus trees.

The Argentine ant is an invasive species with a worldwide distribution. It is a major nuisance in southern states including Georgia, South Carolina, Alabama, Mississippi, Louisiana, Florida, Tennessee, and North Carolina, and also in California. In fact, a 2007 survey found that 85 percent of all urban pest control services in California were focused on the Argentine ant.

A common method for managing the Argentine ant has been insecticide sprays. However, the downside of this tactic is that the insecticides can harm non-target organisms that do beneficial things. The misuse of the pesticide sprays can also cause environmental contamination.

As a result of these downsides, research has focused on liquid baits that use a combination of sugar water (to attract the ants) and a small amount of toxicant to kill the ants. The problem with the liquid baits is that they need to be dispensed in bait stations, which are costly to maintain.

“Hydrogels eliminate the need for the bait stations. The hydrogels are applied on the ground where the ants forage. Once an ant finds the hydrogel, it drinks from the surface of it. It then goes back to its nest and shares the toxic liquid with nest mates. The ants also create a trail to the hydrogels that their nest mates will follow,” Tay said.

The hydrogels are designed to be slow-acting, so it takes several days before the ants die. By that time tens of thousands will have ingested the liquid bait.

The hydrogels created by the team are highly absorbent – the material used is similar to what is used in diapers. They retain water so that they will remain attractive to ants for an extended amount of time.

The researchers used sugar water containing 0.0001 percent of the insecticide thiamethoxam in the hydrogels. “This is 100-fold less than it is used in a standard ant gel bait and 1,000 times less concentrated than spray insecticides containing thiamethoxam,” Tay said.

Future research will address the potential use of the hydrogels on other pest insects as well as how quickly the hydrogels biodegrade.

The article, published in Pest Management Science, is called “Development of an alginate hydrogel to deliver aqueous bait for pest ant management.” The research was funded by the California Department of Pesticide Regulation and the Early Career Chair in Urban Entomology Fund.