Different Types of Flies: Exploring Fascinating Species and Their Roles in Nature

Flies are fascinating creatures that can be found in a variety of environments across the globe. One might be surprised to learn that there are over 100,000 different kinds of flies identified by scientists worldwide, including common ones like house flies, horse flies, gnats, midges, and mosquitoes1. All these flies belong to the insect order … Read more

Do Flies Have Brains? Unraveling the Mystery Behind Insect Intelligence

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

Basic Structure

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.

Major Components

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:

Insect Brain Mammalian Brain
Smaller, simpler Larger, more complex
Fewer neurons More neurons
Limited cortex Developed cortex

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

Head Anatomy

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.

Neural Components

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:

Feature Flies Humans
Brain size Small (3016 neurons) Large (86 billion neurons)
Vision Compound eyes Single-lens eyes
Olfactory organs Antennae 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

Drosophila Melanogaster

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

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

Comparison Table

Technique Resolution Advantages Disadvantages
Light Microscopy 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

Comparison Table

Cognitive Ability Fruit Flies Humans
Memory Yes Yes
Learning Yes Yes
Attention Yes Yes
Navigation Yes Yes

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.

Insect Cognitive Abilities
Flies Basic cognitive abilities, but studies show more complexity than previously known
Bees Advanced memory, problem-solving, communication, and navigational skills
Wasps Facial recognition, memory, and communication
Ants Complex communication, problem-solving, navigational skills, and teamwork
Butterflies 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.

Neural Correlations

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:

Feature Human Brain Fly Brain
Decision-making center Cerebral Cortex Ellipsoid Body
Number of neurons ~86 billion ~100,000
Dopamine involvement 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.

Feature Housefly Vertebrates
Outer covering Exoskeleton Skin
Material made of Chitin Varies
Abdomen structure Segmented Non-segmented
Number of legs 6 0 to 4

Reader Emails

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.

Scuttle Fly

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.

Scuttle Fly

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.
Bill DuPree
Atlanta, GA

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
Date: 06/08/2019
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

Muscid Fly

Dear 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.” 

Muscid Fly

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


Dear Robin,
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.

Fly Head

Read more

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How to Get Rid of Houseflies in Winter: Quick and Effective Solutions

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