The traps of many carnivorous plants are red in colour. This has been widely hypothesized to serve a prey attraction function; colour has also been hypothesized to function as camouflage, preventing prey avoidance. We tested these two hypotheses in situ for the carnivorous plant Drosera rotundifolia. We conducted three separate studies: (i) prey attraction to artificial traps to isolate the influence of colour; (ii) prey attraction to artificial traps on artificial backgrounds to control the degree of contrast and (iii) observation of prey capture by D. rotundifolia to determine the effects of colour on prey capture. Prey were not attracted to green traps and were deterred from red traps. There was no evidence that camouflaged traps caught more prey. For D. rotundifolia, there was a relationship between trap colour and prey capture. However, trap colour may be confounded with other leaf traits. Thus, we conclude that for D. rotundifolia, red trap colour does not serve a prey attraction or camouflage function.
Data from Drosera rotundifolia leaves
These data relate to measurements of the leaves of Drosera rotundifolia plants growing at Thorne Moor, Lincolnshire, UK. Prey were measured directly after removal from the leaf. Leaf colour data were collected electronically by analysis of digital photos. ‘Time’: date of measurement - 1=08/09/2012 2=15/09/2012 3=22/09/2012. ‘Plant’: plant i.d. ‘LeafArea’: Leaf area (mm^2) based on measurement of the longest axis and the axis perpendicular to that. Area calculated assuming leaf is an ellipsoid. ‘PreyCt’: number of captured arthropod prey removed from the leaf. ‘PreyLth’: Length of captured arthropod prey. ‘PreyArea’: Number of arthropod prey per unit leaf area (prey mm^2). ‘TrapL*’: Trap/leaf L*. ‘Trapa*’: Trap/leaf a*. ‘Trapb*’: Trap/leaf b*. ‘BGL*’: Background L*. ‘BGa*’: Background a*. ‘BGb*’: Background b*
Natural_summary.csv
Data from artificial traps placed on natural backgrounds
These data relate to measurements of captured arthropod ‘prey’ removed from different coloured artificial traps placed on the bog surface at Thorne Moor, Lincolnshire, UK. Each record relates to a single prey item. Prey were measured directly. Colour data are from electronic image analysis of digital photos. ‘Time’: date of removal of trap from bog (traps were in place for 7 days) - 1=08/09/2012 2=15/09/2012 3=22/09/2012. ‘Trap’: Trap i.d. TrpClr: Trap colour (Red, Green or transparent/clear). Length: length of prey item (mm). Width: width of prey item (mm). Order: Taxonomic order to which prey item belongs.
Artificial_on_Natural.csv
Data from artificial traps placed on artificial backgrounds
These data relate to measurements of captured arthropod ‘prey’ removed from different coloured artificial traps placed on different coloured artificial ‘backgrounds’ at Thorne Moor, Lincolnshire, UK. Each record relates to a single prey item. ‘Time’: date of removal of trap from bog (traps were in place for 7 days) - 1=08/09/2012 2=15/09/2012 3=22/09/2012. ‘Trap’: trap i.d. TrpClr: Trap colour (Red or green). BGClr: Colour of artificial background (Red or Green). ‘Length’: Length of prey item. ‘Width’: Width of prey item. ‘Order’: Taxonomic order to which prey belongs.
Artificial_Artificial.csv
colour data for artificial traps placed on natural backgrounds
These data relate to measurement of the colour of the artificial traps used in the ‘artificial traps on natural background’ part of the study. Each record related to measurement of the colour of a single trap and its background. Data were measured electronically using image analysis of digital photographs. ‘Trap’: trap i.d. (these relate directly to ‘trap’ in ‘Artificial_On_Natural’. Colour: Trap colour (red, green or clear). ‘TrapL*’: Trap L*. ‘Trapa*’: Trap a*. ‘Trapb*’: Trap b*. ‘BGL*’: background L*. 'BGa*’: Background a*. ‘BGb*’: Background b*. 'DeltaE76’: Delta E76 for difference between trap and background.
A_on_N_Colour.csv
Colour data for artificial traps placed on artificial backgrounds
These data relate to measurement of the colour of the artificial traps and artificial backgrounds used in the ‘artificial traps on artificial background’ part of the study. Each record related to measurement of the colour of a single trap and its background. These traps are a sample created with used in the study, though these traps were not used in the study itself. Data were collected electronically using image analysis of digital photographs. ‘Trap’: Trap i.d. ‘TrpClr’: trap colour. ‘BGClr’: Background colour. ‘TrapL*’: Trap L*. ‘Trapa*’: Trap a*. ‘Trapb*’: Trap b*. ‘BGL*’: background L*. ‘BGa*’: Background a*. ‘BGb*’: Background b*. ‘DeltaE76’: Delta E76 for difference between trap and background.
A_on_A_colour.csv