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Rory McDonnell 1 , Amy Roda 2 and Jocelyn Millar 1

Gastropod attractants: Potential management tool for  Giant African Land Snail Lissachatina fulica ? RESEARCH UPDATE. Rory McDonnell 1 , Amy Roda 2 and Jocelyn Millar 1. 1: Department of Entomology, University of California, Riverside

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Rory McDonnell 1 , Amy Roda 2 and Jocelyn Millar 1

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  1. Gastropod attractants: Potential management tool for Giant African Land Snail Lissachatina fulica?RESEARCH UPDATE Rory McDonnell1, Amy Roda2 and Jocelyn Millar1 1: Department of Entomology, University of California, Riverside 2: CPHST, USDA-APHIS, Subtropical Horticultural Research Station, Miami

  2. Background • Chemical cues play roles in feeding, prey detection, predator avoidance, alarm responses, species recognition & reproduction in gastropods • External attractants e.g. from food sources • Possible pheromones • Sex pheromones • Aggregation pheromones

  3. Sex pheromones Ilyanassa obsoleta Euhadra peliompha exoticsguide.org Photo: Wikimedia Commons • Spawning and breeding in mud snails organized by at least two kairomones and three pheromones • Gland in the head produces a pheromone that elicits courtship and copulation

  4. Aggregation Pheromones Lissachatina oriented towards odor of conspecifics Source reported to be the pedal mucus gland Attractant is a pheromone Source: Chase (1978)

  5. Why no further work to follow up?

  6. Our Approach • Attractants produced by conspecifics • Follow up on preliminary work by Chase from 1978, showing attraction of GAS to odors from conspecifics • Attractants from other sources  Identify and develop attractants from other sources (e.g., food)

  7. 1. Pheromones

  8. Response of Lissachatina fulica to the odor of conspecifics X2 = 24.69, P<0.001, n=20

  9. Aeration chamber for collecting odors from live snails

  10. Odor analysis results • Little difference between snail and control aerations • One compound appeared consistently in snail odor collections 2-diethylaminoethanol

  11. Response of Lissachatinafulicato a 0.01% solution of 2-diethlyaminoethanol X2 = 6.14, P<0.05, n = 14

  12. 2. Other attractants • Fed snails a variety of different foods • With one food item, noticed a distinct oriented mass movement towards the food • Much more pronounced than normal, clearly strong attraction to odors from the food

  13. Attraction to food odors • Pronounced oriented movement towards food source

  14. Replicated bioassays • Two choice bioassay • 1ml of treatment and 1ml control on filter paper • Position of treatment and control switched after each replicate • Snails tested individually to prevent trail-following • Choice made when snail touched the Petri dish or after 45min Treatment Control

  15. Response to steam distillate X2 = 6.07, P<0.05, n = 10 Statistically significant attraction Result: Attractants are extractable and heat stable

  16. Response to ether extract of steam distillate X2 = 6.07, P<0.05, n = 10 Statistically significant attraction Result: Attractant extractable into organic solvent, easier to work with

  17. Response to acid-treated steam distillate X2 =6.00, P<0.05, n = 10 Statistically significant attraction Result: Attractant cannot be amine or other organic base

  18. Response to base-treated steam distillate X2 = 7.00, P<0.05, n = 10 Statistically significant attraction Result: Attractant cannot be organic acid

  19. Response to neutralized ether extract of steam distillate X2 = 20.20, P<0.001, n = 10 Statistically significant attraction Result: Attractant is one or more neutral compounds in the steam distillate

  20. Response to methanol elution of steam distillate volatiles trapped on solid phase extraction cartridge X2 = 8.32, P<0.05, n = 10 Statistically significant attraction Result: Attractant is a moderately polar compound

  21. Conclusion • The attractant is a heat-stable neutral compound(s) that is moderately polar • Some attraction to a partial reconstruction of the compounds in the neutrals fraction

  22. Next steps! Pheromone: 1. Continue to analyze the aeration extracts 2. Testing of pedal mucus gland

  23. Next steps! Food based attractant: 1. Analysis of the neutrals fraction from the steam distillate 2. Development of a fractionation scheme 3. Reconstruction of the volatiles blend for bioassays

  24. Questions? Acknowledgements:  APHIS-PPQ-CPHST for funding to date

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