Insects reappear after the cold: Part 1

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With this year’s early wave of mild spring weather, the insect world is already showing signs of life.

In our region, which falls in the center of the temperate zone, most insects have been out of sight since winter’s first snow cover. Depending on their winter survival strategies, they either dug in under leaves and soil, burrowed into trees or human structures, hid in the depths of ice-covered lakes and ponds, migrated to warmer regions, or died off after laying eggs.

We’re all familiar with insects that use human shelter for their survival. Even during midwinter, you may have discovered bothersome box elder bugs, ladybugs or flies that took shelter inside your house. These creatures occasionally appear on mild winter and spring days after the sun warms walls or windows where they hide. Their intrusion is only temporary, and they’ll try to get outside again as soon as the weather allows.

Outside your house, many insects are already active, but because most of these creatures are either newly-hatched larvae or nymphs surviving from last year, they’re generally very small and easy to miss. If you’re one of those rare people with an enthusiasm for insect life, you can get the jump on the season by doing some up-close exploring on your own. Turn over and inspect any pile of leaves, mulch or rotten wood, and you’ll find an assortment of grubs and larvae, tiny eggs, and active beetles even on the coldest, rainiest and most miserable of spring days. It’s an interesting activity for families itching to spend time in the great outdoors after a long winter.

Among the first spring insects to catch our attention are those that take to the air, such as flies and some of the more diminutive species of bees. It’s startling to suddenly see these creatures buzzing around after we’ve grown accustomed to barren winter skies with only a few birds to watch. Flies are among the fastest-maturing, shortest-lived members of the insect world. For species with lifespans measured in days or weeks, all it takes is a short warm spell to produce a generation of airborne adults from newly hatched eggs. Although the next wave of cold weather may wipe them out, another cluster of eggs is certainly lying in wait for just the right temperatures to hatch.

One of our hardiest winter survivors is the goldenrod gall fly. Over the summer, its larva will burrow into a goldenrod stem and cause a knob or gall to form. The larva turns into a pupa and winters over inside the gall. In the spring, it emerges as an adult. In nearly any field, you can spot the galls on dead and dried up stalks of goldenrod. An interesting family activity is to collect several of these galls and carefully split them open to see the pupae.

Next week: Insects reappear after the cold, Part 2

from the March 28-April 3, 2007, issue

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