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One of my favorite Disney movies is the timeless classic
“Hercules.”It tells the story of a Greek War hero—the strongest man who ever
lived. He was able to heave boulders, slay ferocious monsters, get the girl,
all while staying in tune. Not to be outdone, the Eastern Hercules Beetle (Dynastes tityus) earned its
common name for the same reasons. Well, it can’t keep a tune, but it is one of
the strongest beetles known to humankind. It is able to lift 850 x its own body
weight. Thinking of this in human terms, we would need to be able to lift about
70 tons to match what this beetle can do. To think this very hero which we
speak of lives right here in the Lehigh Valley.
The Eastern Hercules Beetle is truly herculean. Adults grow
to be over two and a half inches long, making them the largest beetle in North
America! This is actually a decrease in size from when it was a baby as some
larvae grow to be almost 5 inches long.
A large portion of the Eastern Hercules Beetle body is its
long, alien like horns that come off the front of the male’s head. While
sometimes used to obtain food, their main function is to act as a sparring
weapon to use against other males. They are very territorial insects, and males
will often duke it out to see who is the toughest, and also to vie for a
female’s attention—think two guys arm wrestling at a bar. A male who can win a
fight is more likely to have a female choose him to mate. The other is the size
of the horns. The size of the horns are a direct reflection of how large the
individual beetle is. Larger beetles invest heavily in making larger horns,
while smaller beetles invest heavily in creating larger reproductive structures
because they will have less opportunities to reproduce. A large, aggressive male should have his pick
of Eastern Hercules females.
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Once a male and female mate, the female will deposit her
eggs in a rotting log she finds in the forest. The eggs will hatch and the
larva will crawl and develop within the decaying log, feeding and growing for
about 18 months before entering their pupal stage. It will emerge as an adult
in the spring time, and is active
generally at night. During the day you may find the beetle resting/feeding
in a compost pile in your yard, but generally you will see them more around
your outside lights—specifically if you live near a hardwood forest. This makes
it less common to see these beetles around the Lehigh Valley, unless you live
in a very unpopulated region.
The Eastern Hercules Beetle is a frequent inhabitant of
hardwood forests. While it prefers Ash and Cherry, the beetle is not that
picky, and would “rough it” in Oak or Elm if the need arose. It climbs on the
trees, preferring to remain in the shade and take advantage of the visual
protection that the leaves provide. It’s convenient that the beetle’s number
one source for food happens to be the very tree it lives on—picture living in
an all you can eat buffet restaurant. It grabs twigs off the tree and quickly
whirls them around in its large horns until it finally snaps off of the tree.
It then sucks the sap from the twig, and is momentarily satiated. If the beetle
happens to be so lucky as to find rotting fruit on the ground, it will happily
eat that as well.
As the name suggests the Eastern Hercules Beetle lives in
the Eastern half of the United States—East of the Mississippi river, from New
England all the way to Florida. Unfortunately for the Hercules Beetle, in the
Northeastern United States, there is an infestation of Emerald
Ash Borer’s—insects that eat and subsequently kill the ash tree. Currently,
there is no way to prevent the spread of this pest, and the ash tree forests
are on the verge of dying out. This is bad news for the Hercules Beetle, whose
most beloved habitat and favorite food is the ash tree. It will have to figure
out ways to make up for this lost nutrition, or we may not see this beetle in
the Lehigh Valley. I guess we would have to change its name to the Achilles
Beetle, and the Emerald Ash Borer its Achilles heel.
While looking for food, the beetle must also make sure that
it is not leaving itself an easy target for predators. The Eastern Hercules
Beetle may be the King Kong of the insect world, but it is the juicy steak of
the birds, bats, and small mammals world. Large birds feast on these large
insects. The Coleoptera (Beetles) as a
whole have developed a mechanism for avoiding predation, while Eastern Hercules
Beetles have developed their own novel way of avoiding being lunch.
The Hercules Beetles
are the largest species of beetle in North America. That only hurts them when
they are trying to avoid predators higher up on the food chain. For that, the
Eastern Hercules Beetle has developed a system by which it emits an extremely
foul smelling odor when being pursued by predators—similar to skunks. It
startles and deters the predator long enough for the Beetle to escape,
frightened but unharmed.
Walking through a shady wood on a summer day, one might
stumble across these giants of the insect world. Do not be afraid of its aggressive
looking body—the Eastern Hercules Beetle is completely harmless. Listen closely enough,
and you may be able to hear the “clacking” sound of two males fighting for
territory and a female in the distance. Reflect on the marvelous diversity of
the Beetle family, and be thankful that these beetles aren’t any larger. Then,
maybe, we would have something to worry about. At the very least, we’d have to
start wearing helmets more often.
This post by Chris Greco is licensed under a Creative Commons Attribution 4.0 International License.
