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

Fun With Flatworms!

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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 - PowerPoint PPT Presentation

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Page 1: Fun With Flatworms!

Fun With Flatworms!

Alyssa Morazé, Natalie Moloney,

and Ethan Yip

Page 2: Fun With Flatworms!

Fun With Flatworms!

Alyssa Morazé, Natalie Moloney,

and Ethan Yip

Planaria spp. aggregation response to injured conspecifics

Page 3: Fun With Flatworms!

“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

Page 4: Fun With Flatworms!
Page 5: Fun With Flatworms!

BRIAN D. WISENDEN & MELISSA C. MILLARD

• Tested whether Planarians showed any response when chemical cues from injured conspecifics were introduced (in Dugesia dorotocephala)

• 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

Page 6: Fun With Flatworms!

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

Page 7: Fun With Flatworms!

Materials and Methods

1. Do they actually aggregate?

• 5 flatworms in a petri dish

• 5 minutes to Acclimate• Photograph taken• Image J software

measuring• 3 trials

Three tests to accomplish our goal:

Page 8: Fun With Flatworms!

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

Page 9: Fun With Flatworms!

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

Page 10: Fun With Flatworms!

0 1 2 30

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

Trial Group

Aver

age

near

est n

eigh

bor d

istan

ce (c

m)

Results1. 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).

Page 11: Fun With Flatworms!

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

1 2 30

1

2

3

4

5

6

7

Control Injured Conspecific

Trial Group

Aver

age

Dist

ance

from

Poi

nt o

f Stim

ulus

(cm

)

Figure 4: Side by side comparison of post stimulus response of the control (tank water as stimulus) and the treatment (injured conspecific solution)

Page 12: Fun With Flatworms!

3. Is there group response to injured conspecifics?

Table 2: Average group response (nearest neighbour values in cm) before and after introduction of tank water as stimulus

Pre-Stimulus Post-Stimulus  ANN S.D. ANN S.D. p =Group 1 1.57 0.188 1.43 0.373 0.3469Group 2 1.00 0.373 1.33 0.281 1.349Group 3 x x 0.996 0.181 x

Table 3: Average group response (nearest neighbour values in cm) before and after introduction of ICS as stimulus.

Pre-Stimulus Post-Stimulus  ANN S.D. ANN S.D. p =Group 1 1.23 0.407 1.36 0.405 0.582Group 2 1.34 0.420 1.28 0.323 0.791Group 3 0.946 0.170 1.12 0.344 0.233

No significant difference in ANN analysis before/after introduction of stimulusNo significant difference between control and treatment

Page 13: Fun With Flatworms!

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 Dugesia dorotocephala

This flatworm species doesn’t show antipredator aggregation response

Page 14: Fun With Flatworms!

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