Fig 1.
Labellum patterns of O. heldreichii flowers.
(A) Transformation of a flower pattern to a black and white replica in an elliptical form used for discrimination experiments with honeybees. Patterns from flowers of the same inflorescence (B) appear more similar to each other than patters from flowers of different plant individuals (C).
Fig 2.
Degree of similarity among patterns from three O. heldreichii populations.
Each box consists of 15 comparisons of randomly chosen flowers of the same (dark grey) or from different inflorescences (light grey). Four different features were compared: (A) pattern overlap, (B) pattern symmetry, (C) relative pattern surface area, and (D) contour density. Boxes represent inter-quartile range with median values. Stars indicate statistical differences after Bonferroni correction (***, p<0.00025; **, p<0.0025; *, p<0.0125; n.s., not significant).
Fig 3.
Duration of approach, copulation and post-copulation scanning behavior of Eucera berlandi males on an Ophrys heldreichii flower.
Boxes represent inter-quartile range with median values, whiskers represent the 5 and 95 percentiles.
Fig 4.
Scanning behavior of Eucera berlandi males after pseudocopulation on an Ophrys heldreichii flower (N = 10 flights).
(A) Relative scanning duration at various distances from the flower. (B) Angular deviation of the bees’ longitudinal body axis and the straight line between bee and orchid flower. (C) Bee position during a scanning flight in one representative trial in top view (sequence length 100 seconds). Colors represent the probability of presence in each 5x5mm pixel. The asterisk marks the position of the flower. Error bars show the standard deviation from the mean in (A) and (B).
Fig 5.
Honeybee performance during pattern discrimination experiments on a rotating screen.
(A) Percent correct choices (target landings plus distractor aborts divided by total number of choices) during the pattern discrimination experiment. (B) Distribution of d’scores. Perfect discrimination would result in d’scores of 3.29, whereas values of zero indicate chance level performance. Filled circles show discrimination of pattern from different plants, open circles show discrimination of patterns from the same inflorescence. The square (after 160 decisions) symbolizes the performance in the unrewarded test, the triangle (after 180 decisions) the performance in the transfer test. Stars indicate statistical difference from chance (***p<0.001; n.s., not significant). Statistical tests were performed on d’ scores only (see Results).
Fig 6.
Fast Fourier Transform (FFT) of stimuli used in the honeybee experiments.
Whereas the two types of crosses (A) differ widely in their FFT, the Ophrys pattern of same inflorescences (B) as well as those from different plants (C) show high similarity in their FFTs.