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Ultraviolet photographs and reflectance measurements revealed that lateral sepals were different from the dorsal sepals (fig. 9). The spectra of the pink and white lateral sepals indicated no UV reflection. In contrast, the spectra of the dorsal sepals show reflection in the UV region (320-400 nm) (fig. 9b). Figure 10 shows the loci of the respective flower spectra in a hexagon colour space. Dyer and Chittka (2004) showed that with increasing colour distance between flowers and distractor flowers, less errors were made by foraging bees (fig. 11). Colour distance between the white and pink flowers is measured in hexagon units (Euclidean colour metric); Table 1. The lateral sepals (UV-) of pink and white flowers are separated by only 0.082 colour hexagon units, while pink and white dorsal sepals (UV+) are separated by 0.039 hexagon units. Thus, pink and white lateral sepals are distinguishable to a bee. In contrast, pink and white dorsal sepals (UV+) are perceptually similar to a bee. Therefore, the white vs. pink flowers of Caladenia carnea can thus be discriminated with between 70-90% accuracy (fig. 11). This means that visits to white/pink flower colours may results in occasional pollinator perceptual errors (1-3 errors/10 visits).

Does the UV signal affect the attraction of bees to orchid flowers?

When bees were presented with a choice between two white orchid flowers, one with a UV signal and one without, there was a significant preference for the flower with the UV reflectance (paired t-test: t= 6.949, df= 15, p<0.001, n=16; figure 12).

Do bees display preferences when choosing between pink versus white orchid flowers? When test subjects were presented with a choice between two flower colours, pink and white, there was a significant preference for the white flower (paired t-test: t= -3.484, df= 15, p= 0.003, n=16; figure 13).

Do bees habituate to non-rewarding orchids based on differences in floral coloration?

Bees were found to habituate to non-rewarding flowers, as the mean number of landings by Trigona carbonaria to the flower at the first time stage (T1) were found to be significantly different from the second time stage (T2) for white (paired t-test: t= 8.34, df= 15, p<0.001) and pink flowers (paired t-test: t= 8.11, df= 15, p<0.001) (fig. 14). Habituation rates were found to differ with different flower colours, as the mean number of landings by Trigona carbonaria to the white flower were found to be significantly higher from that of the pink flower (paired t-test: t=3.59, df=15, p=0.003, figure 14). I also looked at delta, which is calculated as the rate of change between landings at the first and second time stage for pink and white flowers separately. Hence, bees were found to habituate faster to pink flowers, as the rate of change was found to be significantly different (paired t-test: t=3.94, df=15, p=0.001). 

The number of landings to a flower were found to be significantly affected by the interaction between the previous flower colour and new flower colour, (two factor ANOVA, F3,28=6.846, p=0.001, figure 15). When the second flower colour presented was the same colour as the previous flower, landings were not significantly different to the second flower (F1,14=4.332 p=0.056). In contrast, when the second flower colour was different 本论文由英语论文网提供整理，提供论文代写，英语论文代写，代写论文，代写英语论文，代写留学生论文，代写英文论文，留学生论文代写相关核心关键词搜索。