How do I get to be 80+ years old and not know basic facts about nature? This week I learned that dragonflies migrate as far as some birds and Monarch butterflies. I shared my summers with dragonflies up at Leech Lake in northern Minnesota, finding the nymphs and their empty shells on the shore and welcoming their emergence as mosquito-catchers. But I didn't know they migrated.
When it’s back-to-school time, North Shore naturalists such as Joe Walewski at Wolf Ridge Environmental Learning Center in Finland, Minn., know to watch the skies for green darners and other dragonflies soaring overhead on their fall migration journey...Like southbound birds that funnel along the North Shore to avoid Lake Superior’s open water, dragonflies also pass by Hawk Ridge Bird Observatory in Duluth — especially on sunny fair-weather days between late August and early September.Last year, Sept. 1 was clearly a favorite day to fly as Hawk Ridge counted 57,000 dragonflies. On Thursday, they counted 35,000, said Sean McLaughlin, lead counter for Hawk Ridge...Counters do estimates by 10s or even hundreds at a time when dragonflies are moving through quickly. Sometimes they’re dense enough to show up on radar like a rain cloud over Duluth.At 3 inches or longer, green darner dragonflies are usually the most numerous and easy to spot, with their vivid green thoraxes and bright blue abdomens. They’ve also been the most studied. Scientists have put tiny trackers on their bodies and learned the insects can cover 70 to 90 miles a day on their way to Gulf states or as far as Panama.More than a dozen species of dragonflies migrate, including white-faced and autumn meadowhawks, wandering gliders, black saddlebags and spot-winged gliders...Like monarch butterflies, migrating dragonflies only travel one way. They mate and lay eggs at the end of their journeys. Eggs hatch into nymphs in both southern and northern states, overwintering in ponds and waterways until they emerge onto land with wings to follow seasonal migration routes.
You learn something every day. Photo via Wikipedia.
" ... migrating dragonflies only travel one way"
ReplyDeleteYes, living here way down the bottom of the Southern hemisphere, we often find massive mounds of used dragonflies ... their one way tickets well and truly punched.
Lol.
I wonder if the migration routes are built in to the DNA of these insects (and birds, and mammals)?
DeleteBirds and mammals could theoretically learn routes from following or accompanying other older, experienced individuals. For Monarchs and dragonflies it would presumably be encoded within the contents of that tapioca-size pearl of an egg. And not just the route, but the "when". Amazing to think about.
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DeleteSame with birds it's innate. Birds use stars and electromagnetic field of the earth. Incredible.
fascinating.
ReplyDeleteThere is a conference here in Northern Illinois called Wild Things. 2 years ago, the keynote speaker was an expert, scientist and researcher on dragonflies. She LOVED the subject matter and it shone through. An interesting thing I learned: dragonflies have a velcro-like attachment on the back of their heads and their upper back. This allows their heads to stay stationary while perched. Their heads in flight will go every which way. Japanese researchers use a method of hypnotizing stationary dragonflies by drawing widening spirals with their fingers, in front of the dragonfly. It is believed that this confuses the dragonfly into thinking it is flying and can escape but the butterfly net is on them before they realize that they haven't moved.
ReplyDeleteWhat an amazing sight that must be to see 35,000 dragonflies pass by. Here in doodah I know when the dragonflies emerge the nighthawks won't be far behind. I saw few nighthawks this year but of course it was too flippin hot to go out and look.
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