Triadica Sebifera

University of New Orleans ScholarWorks@UNO University of New Orleans Theses and Dissertations Dissertations and Theses Spring 5-13-2016 Determining the pollination mechanism of a problematic invasive species in the Gulf South: Triadica sebifera Jennifer Wester Clark University of New Orleans, [email protected] Follow this and additional works at: https://scholarworks.uno.edu/td Part of the Biology Commons, Ecology and Evolutionary Biology Commons, Entomology Commons, and the Forest Management Commons Recommended Citation Clark, Jennifer Wester, "Determining the pollination mechanism of a problematic invasive species in the Gulf South: Triadica sebifera" (2016). University of New Orleans Theses and Dissertations. 2134. https://scholarworks.uno.edu/td/2134 This Thesis is protected by copyright and/or related rights. It has been brought to you by ScholarWorks@UNO with permission from the rights-holder(s). You are free to use this Thesis in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights- holder(s) directly, unless additional rights are indicated by a Creative Commons license in the record and/or on the work itself. This Thesis has been accepted for inclusion in University of New Orleans Theses and Dissertations by an authorized administrator of ScholarWorks@UNO. For more information, please contact [email protected]. Determining the pollination mechanism of a problematic invasive species in the Gulf South: Triadica sebifera A Thesis Submitted to the Graduate Faculty of the University of New Orleans in partial fulfillment of the requirements for the degree of Master of Science in Biological Sciences by Jennifer Wester Clark B.S. University of New Orleans, 2011 May 2016 Acknowledgement I would like to thank my advisor, Dr. Jerome Howard, for his inspiration, advice, and encouragement throughout my project. I would also like to thank my committee members, Dr. Charles Bell and Dr. Philip DeVries, for their guidance and assistance. Thank you to Scott Hereford and staff at the Mississippi Sandhill Crane National Wildlife Refuge and staff at Tulane University’s F. Edward Hebert Riverside Research Center for assisting me when needed. Many thanks to Dr. Mary Clancy for her microscope expertise and to the undergraduate research assistants I had out in the field, Crista, Brittany, and Becky. Special thanks to my lab mates Cara Nighohossian, Lizzie Ruffman, and Robinson Sudan, and fellow graduate students Lauren Gonzalez, Catie Policastro, and Trent Santonastaso for all of their knowledge and encouragement. Lastly, thank you to my wonderful family for their love and encouragement, especially my husband for his support and patience. ii Table of Contents List of Figures ................................................................................................................................ iv List of Tables .................................................................................................................................. v Abstract .......................................................................................................................................... vi Introduction ..................................................................................................................................... 1 Invasive Species .......................................................................................................................... 1 Triadica sebifera characteristics .................................................................................................. 2 Triadica sebifera as an invasive species in the U.S. ................................................................... 4 Methods........................................................................................................................................... 7 Study sites ................................................................................................................................... 7 Sampling design .......................................................................................................................... 9 Self-fertilization survey .............................................................................................................. 9 Receptivity survey .................................................................................................................... 10 Airborne pollen count ............................................................................................................... 11 Insect pollination survey ........................................................................................................... 11 Insect identification ................................................................................................................... 12 Pollen identification .................................................................................................................. 12 Statistical analysis ..................................................................................................................... 12 Results ........................................................................................................................................... 14 Self-fertilization survey ............................................................................................................ 14 Receptivity survey .................................................................................................................... 14 Airborne pollen count ............................................................................................................... 15 Insect pollination survey and identification .............................................................................. 16 Pollen identification .................................................................................................................. 18 Discussion ..................................................................................................................................... 19 References ..................................................................................................................................... 22 Appendix ....................................................................................................................................... 30 Receptivity Data........................................................................................................................ 30 Insect Identification .................................................................................................................. 30 Vita ................................................................................................................................................ 34 iii List of Figures Figure 1: Range of T. sebifera in the U.S. ...................................................................................... 4 Figure 2: Map of Tulane University's F. Edward Hebert Riverside Research Center .................... 8 Figure 3: Map of Mississippi Sandhill Crane National Wildlife Refuge........................................ 9 Figure 4: Bagged inflorescence .................................................................................................... 10 Figure 5: Tagged inflorescence post- exposure ............................................................................ 11 Figure 6: Pollen trap...................................................................................................................... 11 Figure 7: Pollen grains vs. distance from source tree ................................................................... 16 iv List of Tables Table 1: Proportion of fruits developed per test tree in self-fertilization survey .......................... 14 Table 2: Repeated measured ANOVA of fruit set among trees over time ................................... 15 Table 3: Number of pollen grains per microscope field for two trees at varying distances ......... 15 Table 4: Comparison of abundance of taxa visiting at two sites. ................................................. 17 Table 5: Species diversity by order and bee family at both sites .................................................. 18 Table 6: Mean and standard deviation of 5 field views of pollen loads per group ....................... 18 Table 7: Numbers of fruits developed in receptivity exclusion experiment ................................. 30 Table 8: Arthropods collected (ms stands for morphospecies) ..................................................... 30 v Abstract Understanding the ecology of invasive species is vital to curb the homogenizing of ecosystems, yet the pollination mechanisms of the Chinese tallow tree (Triadica sebifera) in its introduced habitat remain ambiguous. This study examines self-pollination, wind pollination, and flower- visiting insects of tallow in a bottomland hardwood forest and Longleaf pine savannah in the U.S. Gulf South. These data suggest that self-pollination and airborne pollination are possible, but likely rare occurrences, although the possibility of apoxisis was not investigated. Seed production in exclusion experiments was significantly less than in open-pollinated flowers, and wind dispersal of tallow pollen dropped to essentially zero 8 meters from the source. Results show that tallow is primarily bee pollinated, with external pollen loads of Apis, Melissodes, and halictids visiting

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