AUGUST
2007

 

 

 

By
Tom Turpin
 
Professor of
Entomology
Purdue University

 

 

 

 

 

8-23-07

Some Fearsome Looking Stags Are Beetles

Male deer are sometimes called stags. The term is probably based on the Old Norse word steggr, or male bird. In the first century, Pliny the Elder made reference to stags in his Natural History book. He pointed out that a stag lives a long time, and its age can be told by teeth or antlers. Pliny also noted that stags shed their antlers but retire to a secret place to do so. 

The stag was held in high regard by people of medieval times. Not only did the animal provide an elusive target for the hunt but food for the table. Antlers of the stag were prized as decorative items. Pictorial renderings of stags were used in art and to adorn crests. Aesop even included the stag in some of his famous fables. In two fables, the antlers of the stag become his downfall. Today, a majestic stag adorns the logo of the Hartford Financial Services Group.

It was those massive antlers of stags that probably contributed to the use of the name for a group of insects. Males of these insects, called stag beetles, possess fearsome-looking jaws that are suggestive of the antlers of deer.

Stag beetles, like deer, are what biologists call sexually dimorphic. That means that males and females have a distinctly different look. Males of deer have horns; females don't. In stag beetles, the males have greatly enlarged mouthparts, compared to females of the same species. Male deer use antlers as weapons as they battle each other for territory or mates. While the function of the enlarged mandibles in stag beetles is not entirely understood, the jaws certainly come into play when males fight with each other.

The brown- or black-colored stag beetles are some of the largest insects found in temperate regions of the world. These beetles were classified in the insect family Lucanidae in 1804 by French entomologist Latreille. The name for the family comes from the name of an ancient district in southern Italy. There are more than 750 species of stag beetles found worldwide.

Some stag beetles measure nearly 2.5 inches in length. Larvae of these insects feed on dead or decaying wood, so the beetles are commonly found in forested areas. One of the largest stag beetles found in the United States is appropriately called the giant or elephant stag beetle. This insect is sometimes called a pinching bug, even though it is not a bug. Furthermore, the insect cannot pinch very hard with those mean-looking mandibles. In fact, the female has mouthparts that are much smaller and can bite harder than the male. A case where some might say that the male's bark is worse than his bite!

The largest and one of the best-known insects in England is the European stag beetle. This beetle has become rare throughout Europe and in England because of the reduction in breeding areas. Breeding habitat includes broad-leafed woodlands and hedgerows with tree stumps and logs. Because of the declining numbers of this impressive insect, the government of Britain has included the beetle as one of the species in its biodiversity action plan.

The species of stag beetles found in North America are not the same as those found in the Old World, but breed in the same type of wooded habitat. And, just as is the case in Europe, as the forests have been removed for agriculture and development, fewer feeding sites are available for larvae of these insects. An additional problem for these beetles is that they are attracted to lights, where they often end up dying.

These changes in the environment mean that human encounters with stag beetles are less common than in the past. That is too bad, because even though these insect stags are not as impressive in size as their mammal namesakes, they are exciting to see—even if it just happens to be in our swimming pool!

 

Writer: Tom Turpin
Editor: Olivia Maddox