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RIFA readings: Guiding questions. When was RIFA introduced? Where was the first recorded invasion? Where did RIFA come from and how did they get here? Be specific. What area(s) of the US is RIFA established? Why is RIFA so successful in the US? List all the problems that RIFA causes.
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RIFA readings: Guiding questions • When was RIFA introduced? Where was the first recorded invasion? • Where did RIFA come from and how did they get here? Be specific. • What area(s) of the US is RIFA established? • Why is RIFA so successful in the US? • List all the problems that RIFA causes. • List methods that RIFA can be controlled by. For each method, state the downsides of each method. • List the two different biocontrol methods that are being used to control RIFA. Explain how the bicontrol method works and state whether it is successful or not.
Problems caused by RIFA • Outcompete multiple species including the native fire ant • Wrecking havoc on native wildlife (ex. Birds) • Economic losses (cost is 1 billion/yr in TX) • Damage of infrastructure • Harm plant ecosystem • Sting hurts!!!
Methods of RIFA Control & downsides to each method • Toxic pesticides – harmful to other living things • Quarantine- costly, hard to implement effectively • Boiling water/kersone/soapy water/shovel- not very effective, must be repeated, only works in small areas • Baits and traps- only effective in very specific conditions • Biocontrol- takes a long time to be effective, doesn’t kill them necessarily, jury still out
Biocontrol methods used to control RIFA How does method work? Is it successful or not? 1. Microsporidium- limited success 2. Phroid fly- doesn’t eliminate all ants
Biocontrol in Central Texas: Fire Ants and Phorid Flies
Effects of Introduced Fire Ants • Horned Lizards endangered species • Affects native fire ants • Affects bird populations • $300 million lost from Texas economy per year! • Stinging of people
Brazilian Phorid Flies Pseudacteonobtusus on U.S. penny Photo: L.E. Gilbert Pseudacteoncurvatus Photo: L.E. Gilbert
Pseudacteonsolenopsidis Phorid flies, Pseudacteonsolenopsidis, always stay in the front of their chosen victim, then quickly move to the side of the ant to inject an egg into the thorax. This female has chosen a large fire ant (Solenopsisinvicta) worker and may harass it up to two minutes before ovipositing. Photo: L.E. Gilbert
Phorid "harpoon" ovipositor extended Pseudacteontricuspis attacks fire ant worker.
After the fly lays its egg in the ant, The larva eventually pupates in the ant’s head and the head falls off. In Costa Rica, leaf-cutting ants have been found still wandering along trails with their nestmates, in spite of the fact that there is nothing inside their heads except for a mature, fat phorid maggot.
Experiment to determine the effect of imported phorid flies on Solenopsisinvicta
Experimental Setup Introduced Fire Ants with no phorids Introduced Fire Ants with phorids Introduced Fire Ants + Native Ants with no phorids Introduced Fire Ants + Native Ants with phorids
Videocamera Bait Setup within each tray
