DOI: 10.5061/dryad.dj0gr
title: Data from: The effect of trap colour and trap-flower distance on prey and pollinator capture in carnivorous Drosera species

description: 1. The functional features of carnivorous plants’ traps have been mostly
 interpreted as adaptations to capture prey. Carnivorous plants that feed
 on insects, however, run the risk that increasing trapping effectiveness
 might in turn reduce reproductive success through capture of pollinators.
 Such a pollinator–prey conflict might play an important role in the
 evolution of trap features. In carnivorous plants with sticky leaves (e.g.
 Drosera, Pinguicula), both spatial distance between traps and flowers and
 their visual signals (e.g. colour, display size) likely play a role in
 attracting prey but it has also been suggested that they affect the risk
 of potential pollinators landing on a trap. It has been reported, for
 example, that red pigmentation in carnivorous plants may lure insect prey
 to traps. This idea remains controversial, however, because colour vision
 of most insects does not extend very far into the red part of the
 spectrum. 2. We tested an alternative hypothesis, namely that red
 pigmentation of the trapping leaves may reduce the risk of a
 pollinator–prey conflict. Experiments were conducted in a natural habitat
 of Drosera arcturi and D. spatulata in the Southern Alps of New Zealand.
 Using sticky model traps similar in shape to Drosera leaf traps and
 flowers, we investigated the effect of colour (green vs. red vs. white)
 and flower-trap distance (flower stalk length and leaf arrangement, that
 is upright as in D. arcturi vs. flat ground rosette as in D. spatulata) on
 composition and abundance of insects landing and being trapped. 3.
 Flower-trap distance had no significant effect on the risk of pollinators
 being trapped but model flowers higher above the ground received more
 pollinator landings. Across all model traps, the number of trapped
 potential pollinators was significantly lower in traps with red leaves
 compared to green ones. 4. The results suggest that the typical red
 pigmentation of the trapping leaves in Drosera may be a way to protect
 pollinators from being attracted and captured. However, our data also
 suggest that pollinator protection via red traps may come with a trade-off
 since total prey capture was also significantly reduced.
description: Juergens et al_Trap
 dataMicrosoft Excel
 worksheet with trap data of insects found on different artificial traps.
 Experiments with white, green, and red artificial sticky traps to test the
 effect of: flower stalk length (2 cm vs. 8 cm) on pollinator attraction;
 trap positioning (on the ground, D. spatulata type, vs. upright, D.
 arcturi type) on prey (excluding pollinators) and pollinator capture;
 presence of flowers on prey and pollinator capture; and trap colour on
 prey and pollinator capture.Figure
 1Drosera arcturi (A and
 C), D. spatulata (B and D), leaf-shape (green and red) and flower-shape
 (white) format of artificial model traps (E), study site at the lower end
 of the Bealey Valley Track, Arthur’s Pass (F).Figure
 2Experiments with white,
 green, and red artificial sticky traps to test the effect of: flower stalk
 length (2 cm vs. 8 cm) on pollinator attraction (A); trap positioning (on
 the ground, D. spatulata type, vs. upright, D. arcturi type) on prey
 (excluding pollinators) and pollinator capture (B, C); presence of flowers
 on prey and pollinator capture (D, E, F); and trap colour on prey and
 pollinator capture (D, E, F). S = sticky, N = non
 stickyFigure 3 - Spectral
 reflectanceSpectral reflectance
 patterns of Drosera arcturi and D. spatulata leaves and flowers, and
 artificial traps (white, green, red).Figure
 4Generalized linear model
 showing the effect of stalk length (2 cm vs. 8 cm) on the average number
 of Drosera pollinators captured on artificial sticky flowers (Fig. 2A) at
 two sites and two days (χ21,60 = 4.86; p &lt; 0.05)Figure
 5Generalized linear model
 showing the effect of different colours (green vs. red) of model leaves
 (Figs 2D, E, F) on number of captured (A) prey (excluding Drosera
 pollinators) and (B) potential Drosera pollinators (All prey: χ21,90 =
 11.72; p&lt;0.001; Pollinators: χ21,90 = 9.15; p&lt;0.01). The presence or
 absence of non-sticky flowers (2 cm and 8 cm) had no effect on capture of
 sticky model leaves (Pollinators: χ21,90 = 0.617; p = 0.734 All prey:
 χ21,90 = 1.35; p = 0.51).Figure
 6Generalized linear
 models showing the effect of trap colour and trap positioning on
 pollinator capture on model leaves (A) and model flowers (B) respectively
 (see Figs 2B, C). (A) Effect of trap colour (χ21,60 = 10.19; p &lt; 0.01)
 on pollinator capture of model leaves. (B) Trap positioning (upright vs.
 on the ground) showed no significant effect on pollinator capture in model
 traps (χ21,60 = 0.245; p &lt; 0.62). (B) Effect of trap positioning
 (χ21,60 = 4.62; p &lt; 0.05) but not trap colour (χ21,60 = 1.85; p &lt;
 0.174) on pollinator capture of model flowers.