EFFECTS OF DIET AND DENSITY ON Lissachatina fulica (STYLOMMATOPHORA: ACHATINIDAE) By KATRINA L. DICKENS A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE UNIVERSITY OF FLORIDA 2016 © 2016 Katrina L. Dickens To Theodora Dickens ACKNOWLEDGMENTS I would like to thank my advisor, Dr. John Capinera, for his mentoring, feedback and advice. I also thank Dr. Trevor Smith for acting as my committee member and for giving me the opportunity to do this research. Also I thank all of the workers at the Department of Agriculture and Consumer Services, Division of Plant Industry in Gainesville, Florida that helped in this research and colony maintenance, specifically Cory Penca, Amy Howe, Jessica McGuire, Shannen Leahy, Shweta Sharma, Addison Mertz, Cason Bartz, and Steven Rowley. 4 TABLE OF CONTENTS page ACKNOWLEDGMENTS .................................................................................................. 4 LIST OF TABLES ............................................................................................................ 7 LIST OF FIGURES .......................................................................................................... 8 ABSTRACT ..................................................................................................................... 9 CHAPTER 1 LITERATURE REVIEW .......................................................................................... 11 Agricultural Pest ...................................................................................................... 11 Nuisance ................................................................................................................. 11 Disease Vector ....................................................................................................... 12 Description .............................................................................................................. 12 Habitat .................................................................................................................... 13 Distribution .............................................................................................................. 14 Control .................................................................................................................... 16 Research Needed ................................................................................................... 19 2 HOST PLANT SUITABILITY ................................................................................... 23 Introduction ............................................................................................................. 23 Methods .................................................................................................................. 24 Results .................................................................................................................... 26 Discussion .............................................................................................................. 27 3 GROWTH AND REPRODUCTION ......................................................................... 34 Introduction ............................................................................................................. 34 Methods .................................................................................................................. 37 Rearing Methods .............................................................................................. 37 Neonate Growth ............................................................................................... 38 Maturity and Reproduction ............................................................................... 38 Pattern of growth ........................................................................................ 40 First oviposition .......................................................................................... 40 Sexual reproduction ................................................................................... 41 Self-fertilization .......................................................................................... 42 Results .................................................................................................................... 43 Growth .............................................................................................................. 43 First Oviposition ................................................................................................ 44 Sexual Reproduction ........................................................................................ 45 Self-Fertilization ................................................................................................ 45 5 Discussion .............................................................................................................. 46 4 EFFECTS OF DENSITY AND FOOD DEPRIVATION ON GROWTH AND SURVIVAL .............................................................................................................. 57 Introduction ............................................................................................................. 57 Methods .................................................................................................................. 59 Density Effects on Growth and Reproduction ................................................... 59 Food Deprivation Effects on Cannibalism......................................................... 61 Results .................................................................................................................... 62 Density Effects on Growth and Reproduction ................................................... 62 Food Deprivation Effects on Cannibalism......................................................... 63 Discussion .............................................................................................................. 63 LIST OF REFERENCES ............................................................................................... 69 BIOGRAPHICAL SKETCH ............................................................................................ 75 6 LIST OF TABLES Table page 2-1 List of known preferred or susceptible host plants of Lissachatina fulica that occur in the snail-infested area of Florida ........................................................... 30 2-2 Twenty-four diet treatments fed to juvenile Lissachatina fulica to assess suitability ............................................................................................................. 30 3-1 Means (± SD), medians, ranges, and sample sizes (number of snails, n) for height and mass of Lissachatina fulica ............................................................... 51 3-2 Means (± SD), medians, ranges, sample sizes (number of cages) for the number of days from hatching for Lissachatina fulica to lay eggs among diet and density treatments. Means (± SD), medians, ranges, sample sizes (number of snails) for the height of Lissachatina fulica at the first egg laying event ................................................................................................................... 51 3-3 Means (± SD), medians, ranges, and sample sizes (n) for the total number of eggs laid per snail, percent egg viability, and clutch sizes among diet treatments for eggs laid before 241 d for paired Lissachatina fulica ................... 52 3-4 Total eggs produced per snail, mean (± SD) egg viability, and mean (± SD) clutch size for egg produced 0-240 d and 0-540 d for solitary and paired Lissachatina fulica regardless of diet .................................................................. 52 3-5 Mean (± SD) eggs laid per snail, egg viability, and clutch size for eggs produced 0-540 d for solitary and paired Lissachatina fulica for each diet ......... 53 4-1 Mean (± SD) height, mass, percent mortality of Lissachatina fulica 240 d after hatch reared at three different density treatments .............................................. 66 4-2 Lissachatina fulica reproduction when reared at three different density treatments: mean (± SD) number of days from hatch to initiation of egg production, estimated number of eggs produced per snail (over a 60-day period), eggs per clutch, and percent egg viability .............................................. 66 7 LIST OF FIGURES Figure page 1-1 Lissachatina fulica shell ...................................................................................... 21 1-2 Shells of five snail species native to Florida and one non-native that may be confused with Lissachatina fulica ....................................................................... 22 2-1 Mean height and mass of newly hatched Lissachatina fulica after 70 d of feeding on a single diet treatment ....................................................................... 32 2-2 Mean percent survival of newly hatched Lissachatina fulica after 70 d of feeding on a single diet treatment ....................................................................... 33 3-1 The effects of rearing Lissachatina fulica at 6 constant temperatures ................ 54 3-2 Growth pattern of Lissachatina fulica reared on a diet of lettuce or synthetic diet. A polynomial regression was fitted on individual measurements for height .................................................................................................................. 55