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Fun With Flatworms!

Fun With Flatworms!. Alyssa Morazé, Natalie Moloney, and Ethan Yip. Fun With Flatworms!. Planaria spp. aggregation response to injured conspecifics. Alyssa Morazé, Natalie Moloney, and Ethan Yip. “Fun” Flatworm Facts. Free living aquatic worms Class Turbellaria Acoelomate

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Fun With Flatworms!

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  1. Fun With Flatworms! Alyssa Morazé, Natalie Moloney, and Ethan Yip

  2. Fun With Flatworms! Planariaspp. aggregation response to injured conspecifics Alyssa Morazé, Natalie Moloney, and Ethan Yip

  3. “Fun” Flatworm Facts • Free living aquatic worms • Class Turbellaria • Acoelomate • Two eye spots called ocelli that are photoreceptors • Negatively phototactic • Abundant tactile and chemoreceptor cells

  4. BRIAN D. WISENDEN & MELISSA C. MILLARD • Tested whether Planarians showed any response when chemical cues from injured conspecifics were introduced (in Dugesiadorotocephala) • Crushed up a conspecific and placed in ‘Danger Zone’ • Test worm immediately turned 180 when in the ‘Danger Zone’ • Did control test with water and found significant differences

  5. So… WHY? • Found other studies that showed natural aggregation in flatworms • Thought back to schooling in fish lab and how social grouping can be a predation response • Found no prior studies linking aggregation to antipredator response in flatworms • We hypothesized that we would see a difference in the tightness of aggregation in response to IC stimulus

  6. Materials and Methods Three tests to accomplish our goal: • Do they actually aggregate? • 5 flatworms in a petri dish • 5 minutes to Acclimate • Photograph taken • Image J software measuring • 3 trials

  7. 2. Do individuals respond to injured conspecifics? • Single flatworm given 5 minutes to acclimate • Photos taken starting at 5 minute mark every 15 seconds • Single planarian crushed • Added to edge of Petri dish • Behaviour of flatworm noted for two minutes at 15 second intervals • 3 trials of Injured Conspecifics and 3 trials of Control of water also used as stimuli • Distance from planaria to edge of Petri dish calculated *Attempting to recreate the results of the Wisenden and Millard Study

  8. 3. Is there group response to injured conspecific? • 5 flatworms/Standard Petri dish • 1 minute acclimation, photo every 15s for 1min • Injured conspecific solution added • Photo every 15s for 2mins • Average Nearest Neighbour Analysis

  9. Results 1. Do they actually aggregate? • Found no significant differences between trials • Showed no tendency towards aggregation or dispersal Figure 1: The mean ± SEM between each flatworm and their nearest neighbour in three different replicates (N=15).

  10. 2. Do individuals respond to injured conspecifics? • Could not replicate the findings of Wisenden and Millard • No significant difference between acclimation period and stimulus • No significant difference between treatment and control Figure 4: Side by side comparison of post stimulus response of the control (tank water as stimulus) and the treatment (injured conspecific solution)

  11. 3. Is there group response to injured conspecifics? • No significant difference in ANN analysis before/after introduction of stimulus • No significant difference between control and treatment

  12. Discussion • ANN values around 1… threshold for clumping/dispersal • Directly contradicted findings of Wisenden & Millard (2001) • Said organisms avoided areas where injured chemical cues present • Directly contradicted findings of Reynierse et al. (1967) • Tested anitpredator response in Dugesiadorotocephala • This flatworm species doesn’t show antipredator aggregation response

  13. Future Avenues • Red light – too intense? • Larger sample size? • Larger area • Single, well identified species of flatworm

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