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

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.

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

White worms

The experimental setup 2 worms per quadrant Inject cue Start timer Count move-ments Stop time @ 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

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 10-15 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

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

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.

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