A widespread North American dragonfly species exhibits a puzzling behavior: some individuals engage in seasonal long distance migration from their natal pond as adults, but other individuals from the same pond remain in its vicinity following maturation. This difference in behavior generates several questions. First, what are the relative evolutionary benefits of the two movement strategies, and why would such contrasting behaviors be maintained in a single population? Second, preliminary analysis suggests that individuals in the two groups may be closely related, which suggests that the mechanism determining which movement strategy an adult pursues may be determined in response to an environment-triggered cue. Nuclear microsatellite DNA will resolve this issue, and raising sibling larvae exposed to different temperature and light cues may reveal the basis to the behavioral plasticity. The combination of nuclear DNA with hydrogen-deuterium and strontium isotopic ratios in migrating adult wings should reveal the scale of movement during the migration process. Third, recent climate change in Canada has altered the migration process.
This project will involve undergraduate and high school students monitoring A. junius emergence patterns. Undergraduates will assist with molecular processing and manipulating larval development. More generally, dragonflies such as A. junius control many insect aquatic and terrestrial pests and assist with water quality biomonitoring.
