These early summer evenings are the best time to observe fireflies, also called lightning bugs, which are actually soft-bodied beetles that communicate silently with pulsating flashes of cold light. Beetles are the dominant life form on this planet, at least in terms of numbers of species. There are some 350,000 described species of beetles and no doubt a huge number that have not yet been specifically identified.
So fireflies are true elongate beetles possessing "taillights" — segments near the ends of their abdomens with which the insect can produce yellowish light. There are 136 species of beetles known as fireflies in eastern North America, and we in Minnesota have about 15 species. Wetlands, wet ditches, tall grassy spots, old fields, forest edges, and sometimes lawns near these more natural areas are good places to observe them.
The flashing is a recognition signal enabling the sexes to find each other. Each firefly species has a characteristic flashing rhythm. The light emitted by these insects is unique in that it generates no heat. It is produced by the oxidation of a substance called luciferin, manufactured in the cells of the light producing organ. Fireflies control the blinking by controlling the amount of air they take in through micro-openings in their abdomens.
From southern Minnesota to the far northern part of the state and beyond, if you want to watch fireworks of the natural kind, get out away from city lights and look for these specks of light, another of nature's wonders.
What's happening outdoors now?
In southern and southwestern Minnesota, we expect field corn to be at least knee-high by the 4th, but often in the last few years it has been four feet or taller. Some areas of the state are very short on precipitation; crops and native plants are under stress. Delphinium and lilies are showy blooming garden plants. Many gardeners hope soon to dig their first new potatoes, sample the first ripe raspberries, and find the first ripe tomato. New cattail flower-heads are turning dark brown in marshes. Wild gooseberries are starting to ripen, and it's time to snack on red mulberries.
The first monarch butterflies of the new generation, since migrants arrived in Minnesota during May, are now on the wing. A trained observer can pick out two dozen different wild bird species in the morning chorus of singers. This is the time for waterfowl to be in flightless conditions. Some purple martins are busy feeding their nestlings. Tree swallow young have begun fledging, and some eastern bluebirds are nesting for the second time. Mosquitoes become bothersome around sunset. Young raccoons are out and about with their mothers.