1. Characteristics of rainfall and its effects on earthworms
Natalie Rideout, Aaryn Tays, Kaitlyn VanKoppen K

2. K

3. Introduction Worm’s habitat is a burrow in moist, compacted soil
Worms that come to the surface after a rainfall are vulnerable to predation
Debate over the reason why earthworms come to the surface
Flooding of the burrows
Oxygen intake
Migration
Seismic vibrations simulating voles digging K

4. Purpose
To determine what aspects of rainfall makes earthworms come to the surface
Tested using
Control, moisture, vibrations, sound and a combination tank with all three stimuli N

5. Hypothesis
We hypothesized that a combination of all the stimuli (vibrations, sound, and moisture) will result in the greatest number of worms coming to the surface. N

6. Methods
10 worms in 5 tanks
Stimuli applied under red light for 2 minutes for each tank
Control, moisture, vibrations, sound and a combination of all three stimuli
Number of worms at surface counted
Before stimulus, during stimulus and in 2 minute intervals for 30 minutes
N Go into detail about how we set up experiment

7. K

8. Preparing to apply stimulus

9. Results Control No worms surfaced Sound Vibrations 2 worms surfaced
Moisture
Mean of 2 worms surfaced during N=3 trials
Range from 0 to 5
Combination
Mean of 1.5 worms surfaced during N=3 trials A

10. Figure 1. Average results for five trials
Figure 1. Average results for five trials. Stimuli included sound, vibration, moisture, and combination (n=10). A control tank was also tested where no stimuli was present. Number of earthworms observed in the moisture stimulus was 33% more than the combination stimulus. A

11. Discussion
The results showed that moisture had the greatest effect on the worms
This disagreed with our hypothesis
No results were obtained from the sound or the control condition
Possible Confounding Variables:
High temperature of lamps
Variable species of earthworms
Grunting technique K

12. Real World Applications
Increase in danger for earthworms to surface
Higher vulnerability to predators
Could help researchers develop ecological plans
More stable population size
Helpful when working in areas of high flood
Harvesting of earthworms by fishermen
Better understanding of why and when earthworms surface N

13. Future Research
Focus on the reason why moisture encourages worms to leave their burrows
Possible explanations include:
Facilitate rapid migration
Avoidance of drowning in burrows
Facilitation of gas exchange A

14. Conclusion
Earthworms preferred to surface at a point with high moisture levels. It is possible this is due to flooded burrows or the need to migrate.
Earthworms showed no preference for sound or vibration. A

15. Questions and Comments