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Asian swallowtail vision: the science and the numbers

Papilio xuthus · order Lepidoptera · Insects: all the numbers

Asian swallowtails have 5 colour channels, including ultraviolet.[1][2][3] Asian swallowtails stop seeing flicker at 107 Hz, against 60 Hz for people.[25]

  • 5colour receptor classesMeasured*
  • 107hertz flicker fusion (motion)Measured

The Asian swallowtail (Papilio xuthus) is an insect in the order Lepidoptera. Its eyes belong to the vision type Butterfly multispectral: four or more receptor types, including red and ultraviolet. Measured in this species: colour, 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 Asian swallowtails see: colour receptors

Asian swallowtail colour receptor peaks, 300 to 700 nmAsian swallowtail: 5 receptor peaks at 360, 400, 440, 520, 600 nm; you: 3 at 421.5, 532, 558.4 nm. ultraviolet300400500600700
Asian swallowtail: 360, 400, 440, 520, 600 nmPeople: 421.5, 532, 558.4 nmWavelength in nanometres

What stands out

  • It has 5 colour receptor classes, including ultraviolet; people have 3.
  • It stops seeing flicker at 107 Hz, against 60 Hz for people in this dataset, so fast motion looks about 1.8 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.

Vision values for the Asian swallowtail (Papilio xuthus), catalogue-v1
DialValueEvidenceSourcesPeople
ColourColour receptors
5 receptor classes: 360 nm (UVS), 400 nm (VS/SWS (violet)), 440 nm (SWS (blue)), 520 nm (MWS (green)), 600 nm (LWS (long))
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)
SharpnessAcuity
0.56 cycles per degree
median of 1 relatives in genus Papilio: Papilio machaon
Estimated[7]Acuity: 63.75 cycles per degree Measured[8][9]
Angle between facets
0.9°
median of 1 relatives in genus Papilio: Papilio machaon
Estimated[7]
Eye type
compound eye
Field of viewNo 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 class Insecta: 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 visionActivity 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
107 Hz
median of 1 bright-light rows (behavioural/whole-eye ERG rows; all rows: [107.0])
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

  1. Kelber et al. 2003
  2. Longcore 2023
  3. van der Kooi CJ, Stavenga DG… 2021
  4. Kirwan
  5. Müller et al. 2009
  6. Thermal Activation and Photoactivation of Visual… 2004
  7. Caves et al. 2018
  8. Kirk et al. 2004
  9. Veilleux et al. 2014
  10. Heesy 2004
  11. Heffner et al. 1992
  12. Campbell & Green 1965
  13. Comparative data for dance fly eye…
  14. Kopania et al. 2025
  15. Anderson et al. 2017
  16. Borges et al. 2018
  17. Wilman et al. 2014
  18. Maor et al. 2017
  19. Jones et al. 2009
  20. Schmitz et al. 2011
  21. Moura et al. 2024
  22. Banks et al. 2015
  23. Cervino et al. 2021
  24. Guareschi et al. 2025
  25. Lafitte et al. 2022
  26. Healy et al. 2013
  27. 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.