MARCH
2007

 

 

 

By
Tom Turpin
 
Professor of
Entomology
Purdue University

 

 

 

 

 

3-08-07

To Insects, A Stinger Is a Handy Thing to Have

Some insects can sting. So can a few other creatures -- for instance, the appropriately named sea animal called a "sting ray." Some ocean-dwelling jellyfish are also stingers. One well-known jellyfish is called the "Portuguese man-of-war." Its name belies the fact that it is a delicate and beautiful animal. A sinister side to this jellyfish -- and the basis for its name -- is a painful sting. A sting sometimes accidentally discovered when wayward jellyfish encounter folks frolicking in the surf of a sun-drenched ocean beach.

But most people don't have to travel to some distant ocean shore to have an encounter with nature's stingers. That's because land-dwelling creatures also possess equipment necessary to deliver a sting.

Not just animals but some plants, such as the stinging nettle. This common perennial grows in moist areas of forests or disturbed shady sites. It is an early spring plant and is sometimes cooked and eaten as a spinach substitute. The plant possesses tiny, hollow hairs on stems and the edges of leaves. These hairs break off when touched and release an acid that burns and irritates the skin.

Some insect caterpillars also possess stinging hairs. Like stinging plants, stinging caterpillars are passive stingers. That means to be stung by a plant or caterpillar an animal has to initiate the contact. Avoiding touching these passive stingers prevents being stung.

Many stinging caterpillars are brightly colored or distinctively marked. Scientists call such markings including red and orange colors "warning coloration." Warning colors frequently indicate that the creature has the ability to provide a sting and should not be touched. "Beautiful to behold, but dangerous to touch" could be an advertising slogan for stinging caterpillars.

The most recognized stingers of the insect world are bees, wasps and ants. All are classified in the insect order Hymenoptera in which the stinger is a modification of the female ovipositor. The ovipositor is an egg-laying device. Therefore, all stinging bees, ants and wasps are females.

Stinging behavior among bees, wasps and ants falls into one of two general categories. First is what some people call "offensive stinging." These insects, primarily solitary wasps, use their stingers to kill or paralyze animals, such as insects and spiders, to feed to their offspring. Cicada killers sting cicadas for this reason. Organ-pipe mud daubers use their stingers to immobilize spiders that become food for their offspring. In general, such insects do not use their stingers on non-prey animals.

That is not the case for social insects that sting. These insects sting to defend themselves or their nest. Appropriately, such insects are called "defensive stingers." In general, the chemicals that defensive stinging insects inject create a maximum amount of immediate pain in the victim. After all, the purpose for such stinging behavior is to discourage the animal from harming the insect or their nest, so "more pain, more gain!"

In addition to the immediate pain the toxins in these stings provide, there is a lingering effect as well. The sting can result in redness, swelling and soreness in the affected area that can last for days. The lingering affect of a sting serves to remind the animal that it is best to avoid encounters of the stinging kind.

Some animals, including people, are more susceptible to toxins of stinging insects than other animals of the same species. For such people, a single sting can cause anaphylactic shock and result in death. Such people carry a bee sting kit to deal with an unfortunate encounter with a stinging insect.

So which insects are defensive stingers to be avoided? Honey bees, bumble bees, the wasps that construct nests of paper, and some ants are the most likely stingers. It's best to leave these insects alone. They don't go out looking for a fight, but are a little defensive when it comes to their personal safety or their nest. In which case, a stinger is used to make a point!

 

Writer: Tom Turpin
Editor: Olivia Maddox