JUNE
1989

 

 

 

By
Tom Turpin
 
Professor of
Entomology
Purdue University

 

 

 

 

 

6-23-89

FLY-BY-NIGHT BEETLES

Each year, thousands of beetles arrive in the spring to attend Mother Nature's annual; “coming out” party for insects.  Appropriately, these debutantes are called May or June beetles.

June beetles are well-known to most homeowners and gardeners. In the adult stage, these beetles feed on the foliage of broadleaf plants.  In their larval stage, called white grubs, they feed o the roots of grass.  In either case they can cause sever damage to the plants attacked.

So what's a person to do when faced with white grubs in the lawn?  Some rely on natural control measures, such as moles and skunks, which feed on the white grubs.  Most people, preferring instead to prevent further damage to their lawns, choose to use insecticides.  However, chemical control of white grubs is only effective when applied to lawns in early spring or late summer.

These insects have an interesting life cycle.  Most species overwinter as mature adults in the soil.  In the spring, the adults burrow from the soil and fly about, feed on leaves, mate and lay eggs.  Larvae feed on organic matter in the soil.  During the winter or under dry conditions, the larvae burrow deeper in the soil.  They return to the surface as soil temperature or moisture content increases.

Some June beetles, like the Japanese beetle, spend only one year feeding as larva.  Other species spend two or three years in the larval stage.

Adult June beetles are night fliers.  The fact that they fly at all is a minor miracle of the world of nature.  These beetles are compactly built, sort of sumo wrestlers of the insect world.   Like all beetles, their front wings are modified into elytra.  These shell-like covers protect the insect's body and conceal the hind wings.  When a beetle takes flight, it must move the elytra forward and unfold the membraneous hind wings.

June beetles look awkward in flight.  However, their takeoffs and flight are almost graceful compared to their landings, which fit nicely into the category of “crash”!  Beetles just fold up their wings and drop in.  In fact, the poet James Whitcomb Riley once described the flight of June beetles as “bumping along the dusk.”

June beetles are attracted to lights.  Frequently during spring and early summer months, quiet evenings are punctuated with the sounds of June beetles crashing into lighted window panes.  Such grounded beetles, apparently no worse for the wear, repack their wings under the elytra and proceed on foot.

Prowling neighborhood cats have discovered that the ground below lighted windows provides a veritable smorgasbord of crunchy morsels, especially during heavy flights of June bugs.  At least June beetles are good for something.

 

Writer: Tom Turpin
Editor: Olivia Maddox