1. Hello: Thank you for coming
Hello: Thank you for coming. I’m a biosciences student working towards a degree in ecology and evolutionary biology. I plan to attend grad school for entomology.
This is part of the EEB senior research program, and I plan to talk to you today about the :::: TITLE::::
Behavioral response of the green darner dragonfly, Anax junius, to conspecific and predator chemical cues
Eric Hanson, Linda Fuselier – MSUM Biosciences Dept. – Moorhead, MN

2. Introduction Predator/prey relationships Predation risk
Prey must posses physiological, morphological, or behavioral traits to avoid predators
Recognition of a predator is the first step in avoiding predation - can be done through chemical cues
Predation risk
Accurate antipredator responses offer a trade-off between fitness and safety
Anti-predatory behavior usually include reduction of movements, refuge use, or fleeing
Chemosensory cues
Chemicals released from blood or glands (in the skin) into the water
Predator/prey relationships - FIRST LET ME DEFINE PREDATORS; PREDATORS CAN BE ANYTHING FROM A LARGER CONSPECIFIC TO A FISH OR A BIRD.
PREY MUST POSSES TRAITS, SUCH AS A PHYSIOLOGICAL, MORPHOLOGICAL, OR BEHAVIOR TRAIT THAT ALLOWS THEM TO AVOID PREDATION.
Chemisensory cue
- Explain how a cue is released - TELL A STORY ABOUT HOW A DRAGONFLY LARVAE IS ATTACKED BY A BLUEGILL; ANTI-PREDATOR RESPONSES CAN BE A FORM OF KIN SELECTION. THE LARVAE BEING ATTACKED IS TORN APART BY THE BLUEGILL’S GILL RAKERS AND THE CHEMICAL FROM THAT CONSPECIFIC IS EXUDED INTO THE WATER. A NEARBY RELATIVE (SINCE INDIVIDUALS IN A GROUP ARE USUALLY RELATED) SENSES THE CUE AND REACTS BY AVOIDING BEING EATEN. THIS IS A GOOD EXAMPLE OF KIN SELECTION.

3. Methods Cue preparation Habitat
Conspecific cue – 104 frozen vials (10ml each)
34.75 g/L (dead conspecific parts)
Perch cue – frozen in 50ml plastic vials
2 small perch/4 liters water
Habitat
Rubbermaid “shoeboxes”
Mesh
Sprig of artificial vegetation - refuge

4. White worms

5. The experimental setup 2 worms per quadrant
Inject cue
Start timer
Count move-ments
Stop 5 minutes
2 worms added in each quadrant
Inject cue
Start timer
Count feeding strikes, head movements (1/4 a circle turn), walking movements
Stop timer at 5 minutes

6. Methods Rethought
Count worms left in quadrants after a longer period of time
Limitations: White worms are hard to see
Maybe they are fluorescent under blue light?
Observe for a longer period of time
Spend minutes after release of cue
Find a better food source
Observe for a longer period of time
- OBSERVED THEM MOVING AROUND AFTER THE 5 MINUTE SAMPLING PERIOD
Better food source?
- SOMETHING THAT THEY EAT MORE ACTIVELY - WOULD HELP GET SIGNIFICANT DATA

7. Expectations
Conspecific anti-predator response; indicated by less walking movements, head movements, and feeding strikes
No reduction of movements with control and perch cues
Larger head width individuals will show less anti-predator response than smaller head widths
Talk about the differences in the cues. Perch cue - shouldn’t react, Conspecific (dead dragonfly) cue - should show anti-predator behavior, and control - no reaction

8. Future Research Opportunities
Novel predator cue
Run 1 conditioning trial
Conspecific + perch cue
Then perch cue only
Antipredator response expected with only perch cue
Using novel predator cues, we will be able to determine if dragonfly larvae are capable of associate learning. There is not a lot of data on invertebrate learning. Associative learning is important to know because it will allow us to further understand their role in the environment.

9. Acknowledgements Linda Fuselier – Advisor Data Collectors
Molly Dowling
Katie Berning
Andy Berning
~QUESTIONS?