The Effect Of Phorid Flies On Imported Fire Ant Soenopsis Invicta Foraging

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ACKNOWLEDGEMENT

I would take this opportunity to thank my research supervisor, family and friends for their support and guidance without which this research would not have been possible

DECLARATION

I, [type your full first names and surname here], declare that the contents of this dissertation/thesis represent my own unaided work, and that the dissertation/thesis has not previously been submitted for academic examination towards any qualification. Furthermore, it represents my own opinions and not necessarily those of the University (Bardhan, 2001, 467).

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TABLE OF CONTENTS

CHAPTER 1: INTRODUCTION5

CHAPTER 2: MATERIALS AND METHODS7

2.1. Imported fire ants7

2.2. Phorid flies7

2.3. Lab report 18

2.4. Lab report 29

2.5. Statistical analysis10

CHAPTER 3: RESULTS12

3.1. Lab report 112

3.2. Lab report 215

Chapter 4: Discussion17

References19

CHAPTER 1: INTRODUCTION

Two species of imported fire ants, Solenopsis spp. (Hymenoptera: Formicidae) were accidentally introduced from South America into southern United States (U.S.) in the past century. The black imported fire ant (black IFA), Solenopsis richteri Forel was introduced around 1918 followed by the introduction of the red imported fire ant (red IFA), Solenopsis invicta Buren in the early 1930s. Both species are believed to have entered the U.S. through the port of Mobile, Alabama, spreading northward in Alabama and into neighboring states (Wilson, 1958). Hybridization between S. invicta and S. richteri (producing hybrid IFA) has been documented in Alabama, Mississippi, Georgia, and Tennessee. These invasive fire ants are now widely distributed throughout the southern U.S. inhabiting more than 320 million acres (Williams et al., 2003) and causing a multitude of problems for humans, domestic animals, and agriculture in the region.

Four species of Pseudacteon decapitating phorid flies (Diptera: Phoridae) have been introduced from South America in the past decade as classical biological control agents of imported fire ants in southern U.S. The two key species were Pseudacteon tricuspisBorgmeier and Pseudacteon curvatus Borgmeier ( [Porter and Gilbert, 2004] and [Vazquez and Porter, 2005]). One of the early successful introductions of phorid flies in southern U.S. involved a biotype of P. tricuspis collected from Jaguariuna, Brazil in 1996 on red IFA ( [Porter and Alonso, 1999], [Porter et al., 2004] and [Pereira and Porter, 2006]). This biotype is now well established in several southern states (Pereira and Porter, 2006).

Parasitism has been used as the ultimate parameter for determining host specificity and preference in phorid flies ( [Porter and Briano, 2000] and [Vazquez et al., 2004]). However, studies have showed that parasitism rates of phorid flies on ants are consistently less that 5% in the field ( [Feener, 1981], [Morrison et al., 1997] and [Morrison and Porter, 2005]), suggesting that the direct effect of ant mortality in the field due to phorid flies is very low. On the contrary, pre-parasitization behaviors of phorid flies (e.g., hovering and attack attempts) resulted in a 50% decrease in food retrieval by fire ants (Morrison, 1999), suggesting that these behaviors may play very important roles in the effectiveness of phorid flies as ant biological control agents.

The main objective of this study was to determine host preferences in both sexes of P. tricuspis (Jaguariuna biotype) and P. curvatus (Formosa biotype) by testing their relative attraction to the three imported fire ant species/forms in multiple choice flight ...