Do flies possess cognitive abilities? This question has stirred the curiosity of many researchers. Recent studies reveal that flies, specifically fruit flies, exhibit more advanced brain functions than previously thought.
One such study conducted at the University of California San Diego’s Kavli Institute for Brain and Mind demonstrates that fruit flies exhibit complex cognitive processes. This finding challenges our understanding of these tiny creatures and sets the stage for improved research on their vision and behavior.
So, the answer is yes, flies do have brains. In fact, their brains are responsible for a variety of intriguing abilities – from their fascinating navigation skills to their unique color vision. As we delve deeper into this area of research, we continue to unravel the hidden secrets of these tiny yet complex beings.
The Insect Brain
Insects have brains with neurons connected in intricate networks. The insect brain is typically divided into three major regions, each responsible for various functions.
- Protocerebrum: associated with visual processing
- Deutocerebrum: connected to the antennae
- Tritocerebrum: links the brain to the ventral nerve cord
For example, the complete wiring map of a larval fruit fly brain can provide valuable data for studies involving network architecture and machine learning.
Some key components within the insect brain have evolved to perform specific tasks. Prominent ones include:
- Central complex: important for locomotion, spatial memory, and decision-making
- Mushroom bodies: crucial for learning, memory, and olfactory processing
A comparative look at an insect brain vs. mammalian brain:
|Larger, more complex
As seen, the insect brain may be smaller and simpler than a mammalian brain, but it still exhibits complex functions like learning, memory, and decision-making.
Flies and Their Brain
Flies have a distinct head anatomy, which includes several key features:
- Compound eyes: Large, spherical, and made up of multiple individual lenses called ommatidia
- Antennae: Sensory organs for detecting odor, taste, and air movement
- Proboscis: A specialized mouthpart used for feeding and tasting liquids
These features allow flies to have advanced sensory perceptions and effectively navigate their environment.
The brain of a fly is more sophisticated than previously thought. A study from the University of California San Diego discovered that fruit flies (Drosophila melanogaster) have advanced cognitive abilities. Additionally, the connectome of an insect brain was mapped, revealing intricate networks of interconnected neurons in the Drosophila larva.
Here’s a comparison table showing some key differences between flies and human brain anatomy:
|Small (3016 neurons)
|Large (86 billion neurons)
|Olfactory bulb (nose)
In summary, flies do have brains with unique anatomical features that help them navigate and perceive their environment more effectively. Their compound eyes, antennae, and proboscis all play crucial roles in their sensory perception and feeding behaviors. Though smaller and simpler than human brains, fly brains reveal fascinating neural networks that contribute to their complex cognitive abilities.
The Fruit Fly Brain
The fruit fly, Drosophila melanogaster, is a widely studied model organism in the field of genetics and neuroscience. Its compact yet complex brain structure offers insights into the function of neurons and brain organization. A recent achievement by scientists includes the completion of the first map of an insect brain for the fruit fly larva. This groundbreaking connectome consists of 3,016 neurons and 548,000 connections between them.
Research has also shown that fruit flies possess more sophisticated cognitive abilities than previously assumed. Experiments conducted in virtual reality environments indicated that fruit flies respond to stimuli in ways that demonstrate higher cognitive capabilities and decision-making.
Mushroom bodies are specialized structures in the brains of fruit flies that play a significant role in learning and memory. These mushroom-shaped clusters of neurons are critical in processing sensory information and decision-making.
Key features of fruit fly mushroom bodies include:
- Integration of multimodal sensory inputs
- Role in learning and memory formation
- Involvement in decision-making processes
Overall, the fruit fly brain, particularly Drosophila melanogaster, provides researchers with a valuable model to explore neural circuits, cognitive functions, and mechanisms underlying complex behaviors. The detailed connectome and understanding of structures like mushroom bodies help shed light on the intricacies of brain organization and function.
Studying Fly Brains
Janelia Research Campus
The Janelia Research Campus, part of the Howard Hughes Medical Institute, has been at the forefront of studying fruit fly brains. They employ cutting-edge techniques to reveal the complex structures and neural networks within these tiny brains.
- Focused on understanding neural circuits
- Uses the fruit fly Drosophila melanogaster as a model organism
Focused-Ion Beam Scanning Electron Microscopy
One of the advanced techniques employed for studying fruit fly brains is Focused-Ion Beam Scanning Electron Microscopy (FIB-SEM). This method enables researchers to create detailed, three-dimensional images of fly brains, accelerating the progress in understanding the connectome, or the wiring diagram of the brain.
Using an electron microscope allows for high-resolution imaging, capturing every neuron and synapse. The fly brain project at Janelia produced a dataset called hemibrain, covering a significant portion of the fruit fly’s brain. The FlyEM team has been instrumental in advancing this research.
Pros and Cons of FIB-SEM
- High-resolution, 3D imaging
- Detailed view of neural circuits
- Time-consuming process
- Requires extensive data processing
|Lower resolution compared to FIB-SEM
|Faster, less expensive
|Less detailed, limited depth imaging
|Focused-Ion Beam (FIB)
|Scanning Electron Microscopy (SEM)
|High-resolution, 3D imaging
|Time-consuming, extensive data processing
In conclusion, the efforts of Janelia Research Campus and the application of FIB-SEM provide valuable insights into the fruit fly brain, greatly contributing to our broader understanding of neuroanatomy and neural circuits.
Cognitive Abilities of Flies
Memory and Learning
Fruit flies (Drosophila melanogaster) have been found to possess more advanced cognitive abilities than previously believed. They can form memories and learn from their experiences. For instance, fruit flies can associate a specific smell with a reward or punishment, and use this memory to guide their future behavior.
Researchers designed a custom-built immersive virtual reality environment to study fruit flies’ behavior. By manipulating the flies’ neurogenetics, they could observe how the flies learn and adapt their actions in this environment.
Attention and Navigation
Flies can navigate complex environments and devote their attention to specific sensory information. They do this by utilizing neural pathways in their brains to process and respond to a variety of stimuli.
Attention in flies can be seen when they respond to their surroundings, such as avoiding obstacles or moving towards food sources. Fruit flies rely on their visual system for navigation, and they can discriminate colors and use the differences in wavelengths to identify specific objects.
In summary, the cognitive abilities of flies include:
- Memory formation
- Learning from experiences
- Guiding behavior based on previous experiences
- Attention to specific sensory information
- Navigation using visual cues
These studies on fruit flies not only reveal their sophisticated cognitive capabilities, but also provide insights into the neuroscience of cognition and consciousness, which can benefit other fields, such as human brain studies and artificial intelligence research.
Comparing Fly Brains with Other Insects
Bees and Wasps
Bees and wasps possess more complex brains compared to flies. For example, honeybees are known for their advanced cognitive abilities, such as memory, problem-solving, and communication skills. They use a waggle dance to share information about food sources with their hive members.
Wasps, on the other hand, exhibit facial recognition skills, allowing them to remember and recognize their nestmates.
Ants also possess advanced cognitive abilities. They are capable of:
- Complex communication using pheromones
- Building intricate subterranean colonies
- Demonstrating problem-solving and team working skills
Moreover, ants display advanced navigation strategies, using the position of the sun, Earth’s magnetic field, and visual cues to navigate their environment.
In comparison to flies, bees, and ants, butterflies exhibit simpler cognitive capabilities. Despite this, they still show some level of intelligence:
- Ability to learn and remember nectar sources
- Capability of altering their behavior in response to environmental stimuli
The brains of butterflies undergo radical transformation during metamorphosis, from caterpillar to adult stage. Nonetheless, recent studies suggest that memory can be retained in their brain across the development stages, indicating more complex cognitive abilities than previously assumed.
|Basic cognitive abilities, but studies show more complexity than previously known
|Advanced memory, problem-solving, communication, and navigational skills
|Facial recognition, memory, and communication
|Complex communication, problem-solving, navigational skills, and teamwork
|Learning, memory, and response to environmental stimuli
In conclusion, although flies have simpler cognitive abilities than bees, wasps, and ants, their brains still exhibit some level of sophistication.
Fly Brains vs Human Brains
Similarities and Differences
While humans and flies may seem worlds apart, their brains share some striking similarities. For instance, the decision-making centers in the brains of insects and mammals, such as the ellipsoid body in flies and the cerebral cortex in humans, have similar structures and likely share a common evolutionary origin.
On the other hand, there are significant differences in size and complexity between human and fly brains. A human brain contains about 86 billion neurons, while the brain of a fruit fly has only around 100,000 neurons in total.
Recent studies have revealed that the neurotransmitter dopamine plays a crucial role in both humans and flies, particularly in behaviors related to learning, memory formation, and reward. This shared neurotransmitter system suggests that studying flies can contribute valuable insights into understanding human brain diseases such as Parkinson’s, where dopamine levels are disrupted.
A brief comparison table showing some similarities and differences between human and fly brains:
|Number of neurons
|Yes (learning, reward)
|Yes (learning, reward)
To sum up, despite being vastly different organisms, humans and flies possess remarkable similarities in certain brain structures, neural organization, and neurotransmitter systems. These overlaps offer valuable avenues for research into learning, memory, and brain diseases.
Physical Features of Flies
Exoskeleton and Chitin
Houseflies, like other insects, have a hard outer covering called an exoskeleton. This exoskeleton is made up of a material called chitin, which provides protection and support to their bodies. A few distinguishing features of the exoskeleton in houseflies include:
- Lightweight yet strong for flight
- Flexible, allowing movement
Abdomen and Legs
Another crucial aspect of a fly’s physical features is its abdomen and legs. Houseflies, as well as other flies, possess three pairs of legs, giving them six legs in total. The legs play a vital role in the insect’s overall mobility. Some key characteristics are:
- Jointed legs for flexibility
- Hook-like structures to aid in gripping surfaces
Houseflies are soft-bodied insects. Their abdomen’s segmentation allows flexibility and movement. This contributes to their ability to maneuver in flight and while walking or crawling.
|Material made of
|Number of legs
|0 to 4
Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.
Letter 1 – Scuttle Fly
micro bugs living in house, stinging for 2 years!
October 3, 2009
Neighbor kid went to Florida. Kid brought back invisible stinging bugs (not bedbugs). Neighbor kid came to visit and brought her stuff and then we were both infested. They got rid of them with kerosene after a long struggle. I am afraid of using kerosene and gasoline in my house. OTC pesticides are ineffective. They only bite me and my one daughter.
No sleep in TN
Current TN came from Florida.
Dear No sleep in TN,
In our humble opinion, you should not blame the neighbor kid for this situation. It looks to us like you have Biting Midges in the family Ceratopogonidae, which are also called Punkies or No-See-Ums because of their tiny size. Since they are so small, they can enter homes through the mesh in window and door screens. According to BugGuide, they are found near “salt and freshwater marshes, forests, edges of ponds and streams.” and “larvae develop in moist or wet sand, mud, and decaying vegetation of salt and freshwater marshes, ponds and streams.” They would not be breeding inside your home, so they are entering from the outside. BugGuide also indicates: “Many species, mostly in Culicoides, bite humans and can be very annoying.” We will contact Eric Eaton to see if he concurs with our identification and our conclusions about the source of the problem. Tennessee is part of the normal range for Biting Midges known as No-See-Ums.
addendum to micro bugs living in house, stinging for 2 years!
I took the shots with a 100X microscope, so the wasp looking insect is very tiny. It also has a larval form that is round and white with feelers and a pupa from which the black “wasp” hatches. All very tiny.
No sleep in TN
Correction from Eric Eaton
Thanks to the outstanding close-up images, I can easily tell that the “no-see-ums” are actually non-biting flies in the family Phoridae (“scuttle flies“). The larvae breed in decaying organic matter. So, unless the neighbor kid brought spoiled food into the home, he is not to blame. Phorids can be abundant in just about any home. I have had them surviving on residue in the kitchen sink garbage disposal. Since they do not readily carry diseases, and they do not bite, I don’t pay much mind to them. Simply discarding whatever decaying matter they are infesting should end the problem immediately, or very quickly.
Letter 2 – Mating Phorid Flies
Flies for your "Bug Love" page.
I found these flies vigorously engaging in bug love last month in Atlanta, GA. They’re very small and belong to the f amily Phoridae. I’m not sure of the exact species because flies in this family are very hard to identify. Thought you’d like to see the photo.
Hi again Bill,
We always enjoy getting interesting photos from you and this is one of the best. Thanks for allowing us to post it.
Letter 3 – Muscid Fly from the Netherlands
Subject: Bright orange fly
Geographic location of the bug: Netherlands
Time: 12:31 PM EDT
Your letter to the bugman: Hi there,
I came across this fly a few days ago in urban woodland in Groningen, Northern Netherlands. It looked like a bright orange meat fly to my inexpert eye. I’ve never seen anything like it before. It was about six to eight millimetres long and was sitting on vegetation following light rain at around 8am. I would love to know what it is!
Best wishes, thanks for any ideas!
How you want your letter signed: Mick
This is surely a distinctive looking Fly, and the one thing of which we were certain before beginning any research is that the closely spaced eyes indicates it is a male Fly. Since the UK has an extensive selection of insect identification sites, we tried searching the web for orange flies from the UK, and we discovered Phaonia pallida pictured on the Adur Flies site. Wikipedia places it in the family Muscidae with House Flies. According to NatureSpot: “Often seen in woodland” and “Larvae are associated with fungi and rotten wood.”
Letter 4 – Mystery in the garden: Unknown Flies
Flies under row covers every year
April 20, 2010
When I lift my row covers, I have a zillion of these flies trapped underneath in early Spring. I’ve tried to identify them to no avail. Perhaps they originate in my compost.
North Central Arkansas
Flies are often tough for us to identify and we have to confess that we often make mistakes. The behavior you describe seems like it points to Root Maggot Flies in the family Anthomyiidae. It appears to us that the two flies in your photo might even be different species. We will post you letter and images and request assistance from our readership.
Eric Eaton REsponds
Well, there are two different kinds of flies in the image. The one on the left appears to be some kind of “march fly” in the family Bibionidae. The other (on the right) is some kind of muscoid fly (“muscoids” is the term for flies that fall into several related families). Without examining the actual specimen, I can’t tell what it is.
Thanks Eric for confirming our suspicions.
Letter 5 – Request for Experts in Mexico
Bugs and Parasites for TV documentary
Tue, Jan 13, 2009 at 6:20 PM
My name is Sina and I work for a television production company in New Zealand. In March we are sending a crew to Mexico to film for a series about biting bugs and parasites which people can experience when they are travelling. I’m writing because we are having trouble finding contacts for a couple of the stories we are hoping to film, and I’m hoping that someone might have a contact or lead in the US or Mexico? Ideally we would like to speak to someone who is collecting or studying these creatures. We have a presenter who would need to interact with the bug, first hand.
The stories are:
Any help would be much much appreciated!!
We will post your letter as an announcement on our site and hopefully you will get a few responses.
Letter 6 – Shore Fly with Raptorial Front Legs
Subject: Small fly with huge front legs
Location: Southwest Missouri
July 25, 2016 3:06 am
I’ve been searching to ID this bug and think it’s a type of fly. I have an interesting video of it working it’s front legs to stir up food. It was on a leaf blade that was floating in a pond. Thank you for helping!
Signature: Linda Bower
I found it – a Mantis Fly!
“I spent the summer traveling; I got halfway across my back yard.” – Swiss naturalist Louis Agassiz
The trouble with common names in English is that they are not universal and many insects can have the same common name. The beauty of the binomial (Genus species) method of taxonomy is that it is universal, though not necessary permanent when reclassification happens, nor is it easy to learn because names are often in dead languages and often have consonants combined that we have never pronounced together before. The only insect we know with that common name “Mantis Fly” is a Neuropteran in the Family Mantispidae but the name Mantisfly is a compound word. See BugGuide for those Mantisflies. We did locate your insect on BugGuide classified as a Shore Fly in the genus Ochthera, subcategorized as being in the “mantis complex.” Nowhere on the genus page does BugGuide use the name Mantis Fly, however it is stated: “Adults feed on small insects, grasped and held with raptorial forelimbs, and take a variety of prey, including small flies and planthoppers (NC Insect Museum), and can excavate prey from soil using protibial spines; larvae prey primarily on the immature forms of Chironomidae.” At least one poster to BugGuide used the common name Mantis Fly, however it does not seem that the site editors of BugGuide recognize that designation. We are quite excited that your posting is allowing us to create a new page for the Shore Fly family Ephydridae that includes your fly’s genus Ochthera.
Daniel, thank you very much for the information. I’ve updated my postings on Facebook and YouTube. I completely understand what you mean about common names, but very difficult to do when self-taught! You may be interested in these three videos, not for identification, but for weird behavior that I’ve not found in any books or websites.
1) Fragile Forktail Damselfly adult attack: https://www.youtube.com/watch?v=XqhEDu0Jc-E
2) The attack in slow motion: https://www.youtube.com/watch?v=GPV961HDzpQ
3) Fragile Forktail larva attack: https://www.youtube.com/watch?v=k8SBXfCU8OA
I appreciate you and the BugGuide,
Letter 7 – Snail Parasite Fly
Snail Parasite Fly
Fri, Dec 5, 2008 at 12:31 AM
Hi guys, me again,
Got this Snail Parasite Fly. Calliphoridae Amenia imperialis, in my backyard and thought you might like her. The larvae parasite snails amongst leaf litter. The male has eyes that are much closer together but apart from that they are very similar. Quite a beautiful critter really I think
We wish we had a Snail Parasite Fly in Los Angeles. Thanks for keeping our Australian postings freshly stocked. Oz Animals has some nice images.
Letter 8 – Spanish Fly is Frit Fly
insect Southern Spain
I just learned your internet address from TV. And I’m sending you a photo of an insect of which the photo was taken in Southern Spain, to be correct in Marbella. I would very much like to know which insect it is and the name in English but also in Latin, if possible, so I can find out the German name. With kind regards,
We are quite curious where and when our site was on television, and in what context. This is some species of fly, probably in the family Syrphidae, known as Hover Flies or Flower Flies. Eric Eaton provided the following correction: “Hi, Daniel: The Spanish fly is a Frit Fly in the family Chloropidae. Can’t offer more information than that. Eric”
thank you very much for the quick answer. I believe I will never really know which kind of fly this is because there seem to be hundreds. I saw TV this morning, in fact it was ZDF, the first program, and it is called “ZDF Morgenmagazin”. I’m sending you a link to the ZDF-site: http://www.morgenmagazin.zdf .de/ In the middle of the site you find: Die Momasurfer Nr. 28 and when you click on this, you come to this site: http://www.morgenmagazin.zdf.de/ZDFde/inhalt/4/0,1872 ,7153380,00.html and there you will find the hint on your site. With kind regards and thanking you again, yours,
Letter 9 – Spontaneous Generation?
Our houseflies seem to show up seasonally, after the heat of the summer andbefore it turns cold. The warm winter we’ve experienced so far this year inNorth Carolina seems to have extended the flies’ season. While ours seem tobe common houseflies, they tend to congregate in our bathrooms and thekitchen. They aren’t as small as the writer Holly describes "bathroomflies". They look very much like the 1/3/04 picture that Jackie sent.While Jackie and her boyfriend were on vacation and returned to full-grownflies, we NEVER see anything less than an adult fly, no immature flies orlarvae. The cycle is that the adult flies show up over a period of two-three days(about 50-80 in number) then die in the next 3-4. We’ll have some peacethen and the cycle resumes, seemingly tied to the outside temperature–nottoo hot or cold. Of possible interest is that they also afflict one of our next door neighbors at about the same time (September-Octoberish) each year,but not the house on the other side of us (same side of street not far from a creek).
Finally, my questions:
1. What would you use to clean the drains in order to kill and eggs/larvae that might be germinating there?
2. What is the lifespan of the type of fly I’ve described?
3. Since they seem to be breeding inside and are drawn to the light, buzzing around the North-facing windows, is the outside temperature just a coincidence?
4. As there is no obvious organic matter that these flies are breeding in, have you any knowledge of something we could spray around the kitchen baseboards that might help control them?
5. Our dogs like to eat the flies. Is this a potential health threat forthem?
I am grateful for any help you can provide.
You have such a lucid letter. I hope I can be of some help. Bathroom flies are a totally different species with a different appearance. They breed in drains, but other flies do not. You do seem to have cyclical broods appearing. Finding the food source is the true key to solving the problem. A little bit of ancient history provided by Encyclopaedia Britannica: Spontaneous Generation or Abiogenesis was a theory that stated that fully formed living organisms sometimes arise from non-living matter. Aristotle taught the theory as observed fact. The Italian Redi, in 1668, proved that no maggots were "bred" in meat on which flies were prevented by wire screens from laying their eggs.
The fact is, flies seem to have a way of magically appearing. Flies were also, in the days of the persecutions, associated with witches. There is no magic, they are breeding on something. Adult flies will live for several weeks, but the maturation cycle varies with the temperature. It can be as short as a week in warm temperatures. The dogs can eat the flies without harm. Spraying poisons will help kill the adults, but will make your home toxic. Get to the root of the problem and discover the food source. Could there be something dead in the walls? Potatoes rotting under the sink? They are eating something. Good Luck.
You’re a good man. A good man with bad news. The thought of a dead rodent in the wall had flickered in my mind, but I was able to suppress it before it took hold. Until you wrote. I believe I’ll try the vents first. Perhaps the pantry floor. It would be easier if something smelled. I appreciate your thoughtful reply and bonus history lesson very much.