Foxes Lair
  • Home
  • About
    • About Foxes Lair
    • History
    • Landscape and Soils
  • Things To Do
    • Picnic Spots
    • Walk Trails
    • Visit the Arboretum
    • Ride Your Bicycle
    • Scavenger hunt
    • Geocaching and Orienteering
  • Things To See
    • Wildflowers
    • Trees in the Narrogin district
    • Birds
    • Vertebrates
    • Narrogin spiders scorpions ticks
    • Fungi and lichens
  • Foxes Lair seasonal guide
    • December to March
    • April - May
    • June-July
    • August
    • September
    • October
    • November
  • Other great reserves
    • Railway Dam
    • Yilliminning Rock
    • Old Mill Dam
    • Yornaning Dam
    • Contine Hill
    • Highbury Reserve
    • Boyagin Rock
    • Barna Mia
    • Toolibin Lake
    • Newman Block
    • Harrismith Nature Reserve
    • Candy Block
    • Tutanning Nature Reserve
  • 1Foxypress
    • Foxypress
    • Vanishing Farms
  • Contact

Mysteries of Flies Eyes

29/3/2021

2 Comments

 
It is amazing how a single question can open up a new world of knowledge.

When I photographed a couple of fly species pollinating sandalwood flowers, I noticed that the surface of their eyes had facets like gemstones, unlike the round shape of most insects.  I caught house and March flies (an easy task this time of the year) and found the same. Why is this so?.
Picture
Type of blowfly
Picture
Tachinid fly pollinating Frasers dryandra
Picture
Domestic house fly
Picture
March or stable fly. Note spear like cutters around the proboscis
Picture
Rhinidae fly
​I Googled insect vision and was blown away by a wealth of fascinating information that explains so much about insects and how they behave.
PictureLacewing reflected light hexagon from camera flash

​​​Our own eyes provide us with very clear coloured images with good depth perception and can detect fairly rapid changes of movement. We have two large movable eyes with lenses that can change shape and regulate light intake, and a sensitive retina that is backed up by large computing power.
Insects have compound eyes consisting of hundreds of single focus lenses that each have relatively few receptors (ommatidia). Most don't see very clearly but they are good at detecting movement. Ommatidia are packed together in a hexagonal, pentagonal or occasionally square array.

PictureUpward facing pigmented eyes
​Most insects have a less comprehensive colour range than us and don't differentiate orange and red. However they can see ultraviolet colours that we can't. Many flowers have ultraviolet pigments that we can't see, but make patterns specifically designed to attract pollinators. Similarly insect eye colours act a sunglasses that filter out some colours and make their targets and predators more visible.
​
There are many tweaks that different insect have to adapt their vision to their lifestyle.
To get a full understanding please have a look at these fascinating blogs? 
  • Through the compound eye.
  • Insect vision.

​None of this explains why many flies have gemstone facet eyes. A possible link is that they are all fast flying insects that often interact with animals The facets enable more individual ommatidia to provide better focus in fewer directions that would enable them to react faster to say a swatting hand or tail. The slower flying insects below all have more rounded eyes.
Picture
Bee flies
Picture
Stiletto fly
Picture
Soldier fly camouflaged eyes
Picture
Native bee
Picture
Wasp
Picture
Rhinotia suturalis weevils
Picture



Dragonflies are an fast-flying exception but the following features greatly enhance their vision.
  • Enormous eyes with more sensors per ommatidia. 
  • A huge range of colour receptors, and have the fastest movement detecting ability (flicker fusion frequency).
They can detect 300 images per second compared to our 15 to 20.

Have you ever caught a flying dragonfly? 

2 Comments
Andy
14/2/2025 09:57:21 pm

I think the "facets" are reflections of light that appear flat and hexagonal because of the arrangement of the eye pattern, similiar to the hexagonal one created by the camera flash in the lacewing photo.

Reply
Doug Sawkins
19/2/2025 01:57:11 am

I disagree Andy. Most of the images were taken without flash and there is no sign of any cornea

Reply

Your comment will be posted after it is approved.


Leave a Reply.

    Author

    Doug Sawkins is a friend of Foxes Lair 

    Categories

    All
    Animals Other
    Birds
    Disorders Plant Animal
    Fungi Lichens
    History
    Insects Bugs Other Arthropods
    Landscapes Soils
    Other Reserves And Places
    Reptiles
    Spiders Other Arachnids
    Tree
    Walks Other Facilities
    Wasp
    Wildflowers Orchids
    Wildflowers Other Summer Autumn
    Wildflowers Other Winter Spring
    Wildflowers Parasitic

    Archives

    February 2025
    January 2025
    December 2024
    November 2024
    May 2024
    April 2024
    December 2023
    November 2023
    September 2023
    August 2023
    July 2023
    June 2023
    May 2023
    April 2023
    March 2023
    February 2023
    January 2023
    December 2022
    October 2022
    July 2022
    June 2022
    May 2022
    April 2022
    March 2022
    January 2022
    November 2021
    October 2021
    September 2021
    August 2021
    July 2021
    June 2021
    May 2021
    April 2021
    March 2021
    February 2021
    January 2021
    December 2020
    November 2020
    October 2020
    September 2020
    August 2020
    July 2020
    June 2020
    May 2020
    April 2020
    March 2020
    February 2020
    January 2020
    November 2019
    October 2019
    July 2019
    April 2019
    March 2019
    February 2019
    January 2019
    December 2018
    November 2018
    September 2018
    July 2018
    May 2018
    April 2018
    March 2018
    February 2018
    January 2018
    December 2017
    November 2017
    October 2017
    September 2017
    July 2017
    May 2017
    April 2017
    February 2017
    January 2017
    December 2016
    November 2016
    October 2016
    September 2016
    August 2016
    July 2016
    June 2016
    May 2016
    April 2016
    March 2016
    February 2016
    January 2016
    December 2015
    November 2015
    October 2015
    September 2015
    August 2015
    July 2015
    June 2015
    May 2015
    April 2015
    March 2015
    February 2015
    January 2015
    September 2014
    August 2014
    April 2014
    March 2014
    February 2014
    May 2012
    March 2012
    October 2011
    September 2011
    August 2011
    April 2011

© 2015 All Rights Reserved. Doug Sawkins, Australia.