Move over monarchs – make way for the true kings of migration! Dragonflies are fantastic flyers which are familiar to most of us – but did you know that it’s a dragonfly that holds the world record for the longest insect migration? Dragonfly migration is a fascinating but largely-unknown and poorly-understood issue that has been receiving more and more attention in recent years.
Peaking in September, fall dragonfly migration sweeps across Ontario in as grand a fashion as fall monarch migration. Yet this less-obvious, less-visible phenomenon catches most people completely by surprise.
Although it has been documented since the 1880’s in North America, very few people know that dragonflies migrate and fewer know which ones, where to, and why. Scientists have only recently started working out the details. Collaborations such as the Migratory Dragonfly Partnership (MDP) have now formed between researchers, government organizations and citizen scientists to delve deeply into this question.
The study of dragonfly migration has discovered many interesting things:
- Dragonfly migration occurs on every continent except Antarctica.
- Migration can involve anything from sporadic movements to long-distance treks
- Some species probably migrate to survive because they can’t tolerate year-round conditions in any one location.
- Some species are split on migration; when part of the population flies south in the fall, others stay put to over-winter as larvae.
Migration study has shown that dragonflies not only beat Monarchs for the title of longest insect migration but in the case of the wandering glider, they actually double that round-trip record. Their total migration distance is a staggering 16,000-18,000 km, crossing the Indian Ocean between India and Africa!1
The MDP lists only 16 of our 326 North American dragonfly species as confirmed regular migrants. Eleven of these occur in our very own watershed, including four that are being highlighted by the MDP for study. These are the common green darner (Anax junius), black saddlebags (Tramea lacerata), spot-winged glider (Pantala hymenaea) and wandering glider (Pantala flavescens). The first two are by far the most common – you can easily find them skimming over meadows, parks and ponds throughout most of the summer.
Scientists and citizens alike are taking part in studying the movements of migratory dragonflies, recording numbers in spring and fall and submitting specimens for analysis. If you are interested in helping out or looking for resources and information on dragonfly migration, check out the Migratory Dragonfly Partnership website at www.migratorydragonflypartnership.org.
1 Hobson, K. A., Anderson, R. C., Soto, D. X., and Wassenaar, L. I. 2012. Isotopic evidence that Dragonflies (Pantala flavescens) Migrating through the Maldives come from the Northern Indian Subcontinent. PLoS ONE 7(12): e52594.