For Release September 29, 1998

Migration Time

AGRI-VIEWS
by Chuck Otte, County Extension Agent

I don’t think that there is a soul out there who has been outside the past week that hasn’t seen all the butterflies and especially the Monarch Butterflies! 1998 may well go down as the year of the insect. This is my seventeenth year in this job and I can not remember a year when there have been so many different and unusual insects and for me so many that I have never seen before. It started with the 17 year cicadas and just continued going strange.

Was El Nino to blame? Probably not directly, but indirectly we did have some pretty crazy weather that led to some very good conditions for insects to survive and flourish. We had alternating periods of dry and rainy, alternating conditions of above and below normal temperatures and probably the one condition that created the best weather for the insects was the uncommonly high relative humidity. We never had a long enough period of adverse conditions that would cause a great deal of mortality in any insect species.

Many insects migrate for the winter. This may surprise a lot of people. Some insects overwinter as eggs, grasshoppers for example. Some insects overwinter as adults, mosquitoes and most flies are examples of this. Some insects overwinter as a cocoon or pupae, June bugs and many of our moths are examples of this. But some insects simply pack up and head south for the winter. Several dragonfly species including the big green darners that are so plentiful right now are migrants as are the well known Monarch butterfly.

When you look at a butterfly the first thing that strikes you is how fragile they seem to be. To think that many of these Monarchs that we are now seeing have come all the way from southern Canada, they will go all the way to a remote mountainous region of northern Mexico, spend the winter and then these same butterflies will go all the way back north next spring is just mind boggling! But that is exactly what happens.

A Monarch butterfly normally has a life cycle of about one month during the summer. The northward migration normally occurs in early to mid May. Once the overwintering adults reach suitable locations (anywhere from here up into Canada) they will mate, lay eggs and soon die. In most areas there will be three to four broods per year. Starting in late August farther to the north and mid to late September in this area, the Monarchs start a leisurely journey south. They tend to move with north breezes and the cold fronts that also bring us autumn weather. As they move further south they start to funnel down to a more and more concentrated stream. By the time they get to Kansas this stream may only be as wide as the state of Kansas having started off in Canada from the Rockies to the Atlantic.

The trip is somewhat leisurely following the fading summer flowers. If they run into a strong south wind they’ll drop out and wait for better weather visiting as many flowers as they can. In the evening they’ll often group up and spend the night on trees. If you aren’t paying close attention it’ll just look like a bunch of dead or dying leaves on the tree. In the morning they’ll start to wake up and warm up with the sun, flexing their wings for quite a while as they warm up in the rising sun. Once they are warm enough they’ll start to leave the tree often in groups of several hundred at a time!

Keep an eye upward for the next couple of weeks and you’re liable to see dozens of migrating Monarchs against the sky, some quite low and some amazingly high! It’s a sight to see and yet another reminder that winter isn’t so far away after all.....

-30-

Return to Agri-Views Home Page

Return to Ag Home Page