Over time, quotations can acquire legendary status. So it is with some words attributed to British evolutionary biologist J. B. S. Haldane (1892-1964).
It’s said that when asked what he could infer about the Creator from his career in biology, he replied that God must have had, “an inordinate fondness for beetles.”
Whether or not Haldane actually spoke those words, none truer were ever spoken. Of all the living plant and animal species on the planet, 20 percent are beetles.
Of all the animal species on the planet, 25 percent are beetles. Beetles occupy virtually every habitat on earth, though few live in marine ecosystems.
Where they live
About 25,000 species live in North America north of Mexico. They range in size from tiny to bigger than a big man’s fist. Their colors span those of a rainbow, often with an iridescence that’s difficult to describe.
And they eat everything: many are herbivores, many are predators, and some are scavengers. Some, such as long-horned beetles (~ 900 species in North America), have antenna that stretch far beyond their body’s length.
Stag beetles (24 species) have greatly enlarged, ferocious looking mandibles (jaws). Look for them in rotting logs and stumps in the woods. Whirligigs (40 species) swim in frenzied circles like whirling dervishes. Some dung beetles (335 species) make their living by rolling balls of animal waste into which they lay their eggs.
The recyclers
And carrion beetles (30 species) are nature’s ultimate recyclers. Think of a lifestyle, and there’s probably a beetle living it. Most of us encounter beetles every day. Japanese, June and potato beetles are attracted to porch lights and often cling to screen doors at the end of along summer night.
And sometimes we’re confused by their common names. Fireflies, lightning bugs, and lady bugs are neither flies, nor bugs. They are beetles. And so are glowworms, named for their bioluminescent larval stage.
And then there are the weevils. By the most conservative estimates, there are about 350,000 species of beetles in the world. There could be a million or more. And of all those beetles, half are weevils. The iconic cotton boll weevil is just one. (A boll, by the way, is a cotton plant’s seed capsule.)
Compare that to 10,000 birds and 4,600 mammals. With so many species to choose from, it’s difficult to pick favorites.
Click beetles (965 species) certainly make the list. Easy to recognize by a thoracic shield with pointed outer edges directed rearward, many species also have eye spots on the thorax. They get their name by their ability to right themselves if positioned on their back. From that position, they can contact thoracic muscles to snap their bodies into the air and right themselves. The action produces an audible “click” and may startle predators into releasing them.
Tiger beetles
A favorite group of beetles is the tiger beetles (~2,300 species worldwide). As the name implies, they are ferocious predators. They are fast and track down insect prey by running or climbing. Then they use their powerful mandibles to rip their prey into pieces. Larval tiger beetles are even more brutal.
They hide inside a vertical burrow and anchor themselves with abdominal hooks. When unsuspecting prey wanders too near the mouth of the burrow, the larva lunges out and grabs the victim. It uses its large scythe-like jaws to kill the prey and then retreats to the burrow for a peaceful meal.
Bombardier beetles (48 species) defend themselves by engaging in chemical warfare. A cocktail of chemicals held in independent abdominal chambers mix in an outer chamber, where a chemical reaction propels a cloud of nasty, boiling spray. The liquid can burn human skin and leave a scar that lasts for days, so it’s an effective predator deterrent.
Darkling beetles, Tenebrio molitor, are the species I’m most familiar with. There are often several hundred larvae in my refrigerator. Larval darkling beetles are mealworms, which are commonly sold as fish bait and pet food. I offer them in a dish on a platform feeder to my backyard birds.
But my all-time favorite beetles have always been Paul, John, George and Ringo. No, wait, those were The Beatles.
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