Housefly vision: the science and the numbers
Musca domestica · order Diptera · Insects: all the numbers
Flies have 5 colour channels, including ultraviolet.[1][2][3] Their sharpest vision resolves 0.2 cycles per degree, against 63.75 for people in this dataset.[7] Flies stop seeing flicker at 83.3 Hz, against 60 Hz for people.[25]
- 5colour receptor classesMeasured*
- 0.2cycles per degree (sharpness)Measured
- 83.3hertz flicker fusion (motion)Measured
The housefly (Musca domestica) is an insect in the order Diptera. Its eyes belong to the vision type Fast fly (slow-motion world): a compound eye with very fast motion vision, a panoramic field and low sharpness. Measured in this species: colour, sharpness, night vision and motion (flicker fusion). Measured core: measured values on at least 3 of the 6 dials.
This is a simulation built from published eye measurements, not what the animal experiences.
What flies see: colour receptors
Do flies see in slow motion?
Partly. The housefly stops seeing flicker at 83.3 Hz in this catalogue, against 60 Hz for people, and the western honey bee at 220 Hz.[25] The often-quoted 250 Hz is not the housefly value in this catalogue.
What stands out
- It has 5 colour receptor classes, including ultraviolet; people have 3.
- Its sharpest vision resolves 0.2 cycles per degree: the finest stripe pattern it can tell apart from grey.
- It stops seeing flicker at 83.3 Hz, against 60 Hz for people in this dataset, so fast motion looks about 1.4 times slower to it.[26][27]
- Activity pattern: diurnal.
The six dials
Evidence levels: how the tiers work. "Measured" means a value measured in this species; "Estimated" values come from a close relative or an eye-size formula. The last column gives the values for people from the same catalogue.
| Dial | Value | Evidence | Sources | People |
|---|---|---|---|---|
| Colour | Colour receptors 5 receptor classes: 335 nm (UVS), 355 nm (UVS), 460 nm (SWS (blue)), 490 nm (MWS (green)), 530 nm (MWS (green)) measured in this species | Measured (not re-verified) | [1][2][3] | Colour receptors: 3 receptor classes: 421.5 nm (VS/SWS (violet)), 532 nm (MWS (green)), 558.4 nm (LWS (long)) Measured (not re-verified)[2][4][5][6] |
| Ultraviolet yes: at least one receptor peaks in the ultraviolet | Measured (not re-verified) | |||
| Sharpness | Acuity 0.2 cycles per degree median of 1 optical rows (method priority rule); facet_diameter_um: only male rows exist (male value used, labelled); interommatidial_angle_deg: male / drone rows set aside (labelled alternative: 1.75, 3.5) | Measured | [7] | Acuity: 63.75 cycles per degree Measured[8][9] |
| Angle between facets 2.5° minimum (acute-zone) interommatidial angle over sources; within caves2018: minimum (round-1 rule: mean of horizontal and vertical when both exist); interommatidial_angle_deg: male / drone rows set aside (labelled… | Measured | [7] | ||
| Eye type compound eye | ||||
| Field of view | No value in the catalogue. | Binocular overlap: 122.5° Measured[10][11] Total field of view: 200° Measured (not re-verified)[12] Blind area behind the head: 160° Derived[12] Eye placement: frontal Derived[10][11] | ||
| Sharp zones (foveas) | Number of foveas 0 median of 90 relatives in order Diptera: Empis prodromus, Rhamphomyia albidiventris, Rhamphomyia breviventris, Rhamphomyia maculipennis, Rhamphomyia marginata, Rhamphomyia murina | Group default | [13] | Number of foveas: 1 Measured[14] Fovea type: fovea Measured[14] |
| Fovea type none | Group default | [13] | ||
| Night vision | Activity pattern diurnal mode of 1 rows (of 1 rows): diurnal | Measured | [2] | Activity pattern: diurnal Measured (not re-verified)[15][16][17][2][18][19][20][21] Pupil shape: vertical Group default[22][23] Reflective layer (tapetum): no Measured[24] Rods vs cones: cone-dominated Derived[15][16][17][2][18][19][20][21] |
| Rods vs cones no rods (invertebrate photoreceptors) nocturnal -> rod-dominated; crepuscular / cathemeral / mixed -> mixed; diurnal -> cone-dominated | Derived | [2] | ||
| Motion (flicker fusion) | Flicker fusion frequency 83.3 Hz median of 1 rows (no bright-light flag) (behavioural/whole-eye ERG rows; all rows: [83.3]) | Measured | [25] | Flicker fusion frequency: 60 Hz Measured[26][27] |
All insects side by side: Insects: every measurement. Method: how we know what animals see.
Sources
- Kelber et al. 2003
- Longcore 2023
- van der Kooi CJ, Stavenga DG… 2021
- Kirwan
- Müller et al. 2009
- Thermal Activation and Photoactivation of Visual… 2004
- Caves et al. 2018
- Kirk et al. 2004
- Veilleux et al. 2014
- Heesy 2004
- Heffner et al. 1992
- Campbell & Green 1965
- Comparative data for dance fly eye…
- Kopania et al. 2025
- Anderson et al. 2017
- Borges et al. 2018
- Wilman et al. 2014
- Maor et al. 2017
- Jones et al. 2009
- Schmitz et al. 2011
- Moura et al. 2024
- Banks et al. 2015
- Cervino et al. 2021
- Guareschi et al. 2025
- Haarlem et al. 2026
- Healy et al. 2013
- Inger et al. 2014
Every value cites its sources (all sources). Values were extracted from these works and converted (units, medians, derived values); changes are ours, and the listed sources do not endorse this site. Data: catalogue-v1, built 2026-09-29. Accuracy notes: how accurate is this? Method: how we know.