Verifying Floral Evolution Based On 3D Printed Flowers

It is generally accepted that pollinator-mediated selection plays a significant role in flower diversity of angiosperm,but experimental supports are still needed to explore the pollinator mediated selection on a certain floral trait.Based on 3D printing,flowers shape could be controlled easily,and flowers could be similar to the real flowers,allowing achievements of different floral displays and structures.With the aid of 3D printed flowers along with color painting and addition of a certain floral scent,floral evolution could be visualized in laboratory.In this thesis,I observed bumblebee's behaviors of preference and floral constancy on 3D printed flowers with different flower symmetry(zygomorphic and actinomorphic)and flower size(large and small),with the aim of analyzing pollinator mediated selection on floral evolution.The results are as follows:1.I observed bumblebee preference to two flowers with different flower size and Symmetry.When zygomorphic flowers were different in size,the possibility of first choice and visiting times of bumblebees were high to large flowers than that to small flowers,but no significant difference was found on foraging time between large and small flowers,suggesting bumblebees preferred large zygomorphic flowers in comparison with small ones.However,no preferred visitation was found by bumblebees to large and small actinomorphic flowers in terms of first choice,visiting times and foraging time.When flowers of same size were different in sympatry,the possibility of first choice and visiting times of bumblebees were high to zygomorphic and large flowers than that to actinomorphic and large flowers,but no significant difference was found on foraging time between zygomorphic and actinomorphic large flowers,suggesting bumblebees preferred zygomorphic large flowers in comparison with actinomorphic large ones.Similarly,no preferred visitation was found by bumblebees to zygomorphic and actinomorphic small flowers in terms of first choice,visiting times and foraging time.There results indicate that bumblebees prefer large and zygomorphic flowers,in consistent with results from the filed observations.2.I made two types of inflorescences consisting of nine small flowers with different symmetry,and observed bumblebee's preference.I did not find any difference in bumblebee visitation to the different inflorescences in terms of first choice,total foraging time and number of foraged flowers.We suggest that the clustered flowers on one inflorescence might have worked together,and thus different symmetric flowers could play a minor role in affecting pollinator behaviors.Iin addition,there was a significant decrease in the foraging time on one flowers with the increase of sequential visitation for both actinomorphic and zygomorphic small flowers,and visiting sequence had extremely significant effect on foraging time.All these results suggest that sequences of visited flowers within one inflorescence could affect foraging time on single flowers,and this might induce differences in male and female function of different positioned flowers within one inflorescence3.I arranged 16 flowers in four hexagonal cells,with an arrangement of different flower size or symmetry between adjacent flowers,and then I observed flower constancy of bumblebee visitations.Bumblebees did not exhibit constancy during foraging in all experiments.However,when zygomorphic flowers were different in size,bumblebees showed high possibilities to visited large flowers in both zygomophic and actinomophic flowers.Similar patterns were also found when actinomorphic flowers were different in size.In addition,in continuous visitations,bumblebees showed high possibilities to visited large flowers in both zygomorphic and actinomorphic flowers.In contrast,when flowers of same size were different in symmetry,no matter bumblebees started visitation from actinomophic or zygomorphic flowers,bumblebees showed similar possibilities between different symmetrical flowers.All these results suggest that flower constancy of bumblebee visitations might be affected more by flower size than by flower symmetry,and flower constancy was not affected significantly by the sequences of visited flowersConclusively,bumblebees showed great difference in visiting flowers with different size and/or symmetry,which could induce different selective pressures on floral traits to a certain degree.In my thesis,I quantified bumblebee preferences to flowers with different size and symmetry using 3D printed flowers and pollinators,which could mirror the pollinator mediated selection on floral traits.My thesis could open a window to study plant-pollinator relationships using 3D printing technology.