Ants are fascinating creatures, known for their intricate social structures and impressive navigation skills.
However, the idea that humans can smell ants might raise some eyebrows.
It turns out that some species of ants produce distinct odors, which can be detected by our sense of smell.
These odors are a result of chemicals known as pheromones, which ants use to communicate with each other.
People might be able to detect the scent of certain ant species, particularly those with a stronger odor.
For example, some people claim to smell a citrus-like scent when encountering carpenter ants.
In daily life, the ability to smell ants might not seem particularly useful.
However, this intriguing phenomenon could potentially help pest control professionals detect the presence of certain ant species, aiding in their identification and subsequent removal.
So while smelling ants may not be a common experience, it is certainly one that can pique our curiosity and deepen our appreciation for these tiny insects.
Can People Smell Ants? Different Smells Associated with Ant Species
Blue Cheese and Penicillium Mold
Ants emit various smells, some of which resemble familiar odors.
For example, blue cheese’s distinctive aroma is caused by the bacteria Penicillium mold, which produces methyl ketones.
Some ant species release similar compounds, creating a blue cheese smell around their presence.
- Familiar smell: Blue cheese
- Cause: Methyl ketones produced by Penicillium mold
Citronella Ants and Citrusy Scents
Citronella ants (Lasius spp.) produce a distinct citrusy scent when they feel threatened.
This smell, reminiscent of lemongrass, is due to the release of formic acid and other compounds.
- Familiar smell: Citrus
- Cause: Formic acid and other compounds
- Ant species: Citronella ants (Lasius spp.)
Odorous House Ants and their Sweet Aroma
Odorous house ants (Tapinoma sessile) earn their name from the distinctive sweet, coconut-like aroma they release when crushed.
This scent comes from a combination of chemicals in their bodies, including oleic acid.
- Familiar smell: Sweet coconut-like
- Cause: Oleic acid and other chemicals
- Ant species: Odorous house ants (Tapinoma sessile)
Carpenter Ants and Olive Oil
Carpenter ants (Camponotus spp.) emit a vinegary smell when they feel threatened, which is due to the release of formic acid.
In some situations, carpenter ants have been associated with an olive oil smell, likely due to the presence of oleic acid in their bodies.
- Familiar smell: Vinegar and olive oil
- Cause: Formic acid and oleic acid
- Ant species: Carpenter ants (Camponotus spp.)
|Ant Species||Familiar Smell||Chemicals Involved|
|Blue cheese-like ants||Blue cheese||Methyl ketones|
|Citronella ants||Citrus||Formic acid|
|Odorous house ants||Sweet coconut-like||Oleic acid|
|Carpenter ants||Vinegar, olive oil||Formic acid, oleic acid|
Ant Infestations and How to Detect Them by Smell
Natural Causes and Indicators of an Ant Infestation
There are a variety of natural causes that can lead to an ant infestation. Some factors include:
- Presence of food sources
- Damp or moist environments
- Cracks or crevices in walls or foundations
People with an intact sense of smell might be able to detect certain ant species, like trap-jaw ants, which emit a distinctive odor.
However, individuals with anosmia (the inability to perceive smell) may not be able to rely on this method.
Essential Oils as a Detection Tool
Essential oils can be used as a detection tool for ant infestations.
Some oils, like peppermint or eucalyptus, have strong odors that may repel or attract certain species.
Here’s a comparison table of essential oils for ant detection:
|Essential Oil||Attracts or Repels Ants||Pros||Cons|
|Peppermint||Repels||Eco-friendly, non-toxic||May not work on all species|
|Eucalyptus||Repels||Effective, natural||Strong smell, may cause irritation|
By using essential oils with distinct odors, people with anosmia might be able to rely on others around them to help detect an ant infestation through the use of smell.
Just remember that some essential oils might not work on all species or may cause irritation, so always test a small area first.
Can Ants Smell Humans? What About The Other Way Round?
Ants have a highly developed sense of smell due to certain genes. These insects possess four to five times more odor receptors than most other insects.
This exceptional ability is linked to their genetic makeup, with specific genes governing their olfactory system.
Some key points about ant genetic traits related to smell:
- Their genes enable them to detect various chemical signals.
- These signals play a crucial role in communication within ant colonies.
- Genes responsible for olfaction can help ants locate food and detect predators.
Due to these reasons, ants can, in fact, smell humans. A few reports have even indicated that they can distinguish between different body odors!
How Ants Communicate through Smell and Pheromones
Ants primarily use chemicals called pheromones to communicate with each other.
These pheromones are released into the air and sensed by other ants through their antennae. Their sense of smell is important for various functions, including:
- Colony organization
- Defense mechanisms
Ants have an exceptionally high-def sense of smell, with four to five times more odor receptors than most other insects.
Using Smells as Alarm Signals and Defense Mechanism
One primary function of pheromones is to signal danger. Ants release alarm pheromones in response to threats, alerting their nestmates and triggering defensive behaviors.
For example, when a worker ant detects a predator, it may release an alarm pheromone, causing nearby ants to react aggressively or flee the area.
Smelling Out Food Sources and Foraging
In addition to alarm signals, ants use pheromones to guide each other to food sources.
A worker ant that finds food will leave a pheromone trail on its way back to the nest. This trail helps other ants locate the food source and coordinates foraging efforts.
Scientific Research on Smelling Ants
Key Findings in Ant Smell Research
Ants are known for their exceptional sense of smell, possessing four to five times more odor receptors than most other insects1.
This highly developed olfactory system helps them identify food sources and recognize members of their colony.
Scientists have discovered that ants can even detect volatile organic compounds (VOCs) emitted by human cancer cells.
In a study, individual ants were trained rapidly, learning to memorize and reliably detect the odor of cancer cells after just a few trials2.
How We Can Harness Ants’ Ability To Smell
Further research into the impressive olfactory abilities of ants could lead to innovation in medical diagnostic methods.
For instance, the use of trained ants to identify specific diseases based on smell, similar to the current practice of using trained dogs for cancer detection3.
Moreover, exploring the complex chemical ecology and social parasitism of ants4 may help us better understand and appreciate the role of these amazing insects in our ecosystems.
In summary, yes humans might be able to smell ants. People with a very keen sense of smell are often able to detect the pheromones that ants use to communicate with each other.
Some of the common smells that one might expect from nearby ants are citrusy, coconut-like, and olive oil-like smell.
- Ants have an exceptionally high-def sense of smell ↩
- Ants detect cancer cells through volatile organic compounds ↩
- Training dogs for cancer detection ↩
Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about ants. Scroll down to have a look at some of them.
Letter 1 – Bigheaded Ant from Singapore
Mega-ant from Singapore
August 21, 2010 5:51 am
I was fascinated by this ant species since i was young. It is about 1cm long. Any idea what species it is?
At the start of our search for information, we discovered a species called the Bigheaded Ant, Pheidole megacephala, which has an unusual caste system. There are worker ants in two sizes, the minor workers and the more rare major workers that are larger with larger heads.
We found information on the Pest Ants of Florida page, and we learned that this African species has become a major introduced pest in many parts of the world, including Florida.
BugGuide has a photo of the Major Worker that looks very similar to your photograph. The Florida Featured Creatures website has a very extensive profile on the Bigheaded Ant. We have a follow-up question.
In our research, it seems the size difference between the minor and major Bigheaded Ant workers is not as extreme as what is indicated in your photograph. In your sightings over the years, have you always seen the larger ants and smaller ants together?
thanks for the ID! The larger ants only come out when there is food to take back to the nest
Letter 2 – Army Ants from Kenya
Location: Masai Mara, Kenya
December 23, 2010 1:27 pm
I’ve found no Safari ants (Dorylus sp.) on your page, and they’re a very prevalent genus here in East Africa.
They’re known as Siafu in swahili, and also called Army ants for their long uniform columns.
Whenever it rains, they come out in force, forming long, thick columns in search of food.
Their soldier class have fearsome mandibles that can be used as emergency sutures if no other alternative is available. There are anecdotal reports of young or sick people dying from attacks by these ants, but I’ve never seen any hard evidence.
Its not completely unbelievable, though when you see how fast they cover you if you step in the middle of their column by mistake!
I once watched a 12cm centipede get completely overwhelmed when it accidentally ran through a group of these ants. It was only a matter of minutes before there was nothing left of the centipede!
Sorry there are no clear pictures. They move too fast my my camera’s shutter at that proximity.
Thanks again for sending us photos that fill a void in our archives. You action photos of Army Ants and your personal eye witness account are valued contributions to our website. Your photos also illustrate the size discrepancies between the various worker castes in the colony.
The very large ants with the very large heads are soldiers. The picture doesn’t display their huge mandibles very clearly, but there are a few other sites on the internet that do.
Letter 3 – Blue Ant from Australia
Subject: Colourful ant!
Geographic location of the bug: Jindivick, Australia
Time: 08:22 PM EDT
Your letter to the bugman: I have found a few very colourful ants in my vegetable garden recently, and was wondering if you knew the species, it is approximately 1.3 cm long, has some red features across its body and is covered in a metalic green/blue shell, its abdomen sometimes charges like a scorpion tail, but has no visable stinger
Please note that the ants in these photos have not been harmed, and the one in the glass has been promptly released after photographs were taken, as it was within my house
How you want your letter signed: Ben, not into ants – but into this one
Though it is commonly called a Blue Ant, Diamma bicolor, this beautiful creature is actually a flightless, female Flower Wasp. According to Oz Animals: “Blue Ants are not ants at all but the wingless females of a species of Flower Wasp.
The female is has a glossy blue green body with reddish legs. They move across the ground with a rapid restless motion with abdomen raised above the ground. The winged male and is slender and much smaller with more typical wasp appearance. Males have black with white spots on the abdomen.
The female wasps paralyse mole crickets as food for their larvae. The female wasp can give a painful sting if disturbed, but they are not commonly encountered by people.”
Letter 4 – Bug of the Month May 2018: Citronella Ants
Subject: What bugs are these
Geographic location of the bug: Bellevue ohio
Time: 04:42 PM EDT
Your letter to the bugman: I was cleaning out a small section of dirt near my house spring time and lifted a rock and noticed these bugs. I’m not sure what they are and would appreciate the help identifying them.
How you want your letter signed: Zack
We began our research on the Ohioline page Ants In and Around the Home and we found a reference to Larger Yellow Ants and no scientific name with the following information:
“These ants are often mistaken for winged termites since the winged adults swarm through cracks in basement walls or floors, crawl around, and are attracted to lights.
They live in the soil next to the building foundation, under basement floors, in concrete voids or in rotting wood, and feed on honeydew of subterranean aphids and mealybugs, which live on the roots of shrubs planted near residences.
Winged forms are dark brown or blackish-brown with brownish, somewhat clouded wings and bodies measuring 3/8 to 1/4 inch long to the wing tips. Workers are pale yellowish-brown, about 5/32 to 3/16 inch long.
They cluster around cracks and crevices and, when crushed, give off a strong odor, smelling like “citronella” or a certain kind of toilet soap.
They are smooth, shiny, quite hairy, have 12-segmented antennae, one node petiole (long, pointed segment), small eyes on the head, uneven thorax profile, and the anal opening at the end of the abdomen is circular surrounded by a fringe of hairs. Workers stay underground during the day and forage at night.”
Then on BugGuide we found Lemon Ants or Citronella Ants from the genus Lasius (subgenus Acanthomyops) and we believe that is a correct identification for your sighting. We have selected your submission as our Bug of the Month for May 2018.
Letter 5 – Bulldog Ant Alate from Australia
Subject: what is this
Location: Melbourne Australia
April 13, 2015 8:56 pm
what is this bug
This is a Bulldog Ant or Bull Ant in the genus Myrmecia, and it is a winged reproductive individual known as an Alate. According to the Australian Museum site:
“Bull ants are large, alert ants that can grow up to 40 mm They have characteristic large eyes and long, slender mandibles and a potent venom-loaded sting. They have superior vision, able to track and even follow intruders from a distance of 1 metre.
Many species of bull ants have bright red or orange colours on the head or abdomen.” The site also states:
“These ants can deliver painful stings and are aggressive. An ice pack or commercially available spray may be used to relieve the pain of the sting. If there is evidence of an allergic reaction, medical attention should be sought.” There is also an image on Oz Animals.
Letter 6 – Bulldog Ant from Australia
Subject: an insect & an arachnid
Location: melbourne, australia; auckland, new zealand
October 6, 2014 4:22 am
hi folks! you helped me with a bug once before, & i absolutely love your site – hoping you can ID these two critters from my trip to australia & new zealand this month.
the ant is about 5/8″ long & was found on the great ocean road, about 170 miles west of melbourne, australia.
the 1/2″ long spider was found on my neck in auckland, new zealand. 🙂
the third ant i believe i’ve correctly ID’d as a bulldog ant, but the photo came out so nice that i figured i’d submit it, too.
keep up the great work, you wonderful people.
Signature: lish d
Dear lish d,
We love your image of a Bulldog Ant. According to National Geographic Magazine: “Fearless and belligerent, the inch-long bulldog ant of Australia uses her sharp vision and venomous stinger to track and subdue formidable prey. Picture a wasp with its wings ripped off, and you’ll have a good approximation of a bulldog ant. The resemblance is no coincidence: Ants are believed to have evolved from wasplike ancestors some 140 million years ago. The bulldog ant has long been considered one of the oldest ant lineages. But some recent studies suggest that bulldogs appeared no earlier than 100 million years ago, along with an explosion of other ant species that may have accompanied the rise of flowering plants. ” We are unable to identify the creatures in your other two images, and we are posting the unidentified and rather forgetable other Ant which one of our readers may eventually be able to identify. We will not be adding the spider image to this posting as they are not categorized together in our archives, they are not from the same country, and we don’t want to speculate if they met one on one.
Letter 7 – Bullet Ant from Costa Rica
Subject: Bullet Ant
Location: La Selva Biological Station, Costa Rica
July 23, 2016 12:14 am
Thank you so much for your speedy identification of my robber fly. I had a feeling I wouldn’t be able to get a species ID (especially without the specimen itself and with only one photo) but it’s great knowing the order. Here is the bullet ant (Paraponera clavata) photo I mentioned before, also taken with my Canon macro lens. It was a difficult shot to get as these ants are constantly on the move. I am also submitting (separately) photos of a Weevil found in Monteverde and what I suspect to be a caterpillar in the genus Eumorpha.
We have one image of a Bullet Ant from Ecuador in our archive, and at that time we did some research to learn more about Paraponera clavata. Your backlit image is really beautiful.
Letter 8 – California Harvester Ants
California Harvester Ants
Location: Mount Washington, Los Angeles, California
Date: July 19, 2018
Time: 8:15 AM
We suspect none of our readers will be as excited about this posting as we are, but we are happy to report that the colony of California Harvester Ants that has been living on a south facing slope in Mount Washington is still present, though perhaps not for long as every available lot in the neighborhood seems to have a “Notice of Intent” sign for a new construction project. California Harvester Ants are naturally adapted to our Southern California climate and they do not need irrigation to survive, but alas, garden landscaping is responsible for the spread of that scourge, the Argentine Ant, and they have displaced our native Ant species in much of urban Los Angeles.
We also located what we believe to be the back door to the colony right at the edge of the street.
Letter 9 – California Harvester Ants in Mount Washington
California Harvester Ants harvesting
Location: Mount Washington, Los Angeles, California
June 24, 2014 5:18 PM
So, two weeks ago, we noticed some California Harvester Ants along a sunny, southwest facing slope, but we did not have a camera. Today we returned and took some images. Native Ants like the California Harvester Ants are being displaced by invasive exotic species like the dreaded Argentine Ants.
We were inspired by a recent submission of swarming California Harvester Ants from nearby Red Car Property in Silverlake.