Consider the Beetle

Ladies and gentlemen, may I present the unsung beetle. We share the planet with over 400,000 species of beetles. (For perspective, there are only 50,000 animals with backbones: fish, amphibians, reptiles, birds and mammals combined.) In fact, according to Berkeley entomologist Jerry Powell, beetles make up “almost 25% of all known life-forms.” How many kinds of beetles are there yet to be discovered? Scientific guess-timates range into the millions. Beetles have managed this remarkable feat with a winning design and a flair for adaptation.

If there is a food source out there, there is a beetle adapted to exploit it. Entomologist Eric Grissell, author of Insects and Gardens, informs us, “There are cigarette beetles, carpet beetles, ship-timber beetles, sap beetles, drugstore beetles,” (presumably loitering out front), “potato beetles, cucumber beetles and plant-boring beetles of all kinds.” Yes, beetles infesting tobacco products and even pharmaceuticals. Fortunately they are rarely parasitic, and never on humans. As with most of the insect world we indulge in a love/hate relationship with them. We love ladybugs (ladybird beetles actually) munching on garden aphids, we marvel at fireflies (another misnamed beetle, sometimes called lightning bugs), and yet we rail against pine beetles devastating our forests, and snout beetles, better known as weevils, destroying our crops. In my home state, the Colorado potato beetle is hardly a source of pride. It has spread throughout the US, Europe and now Asia, dragging the state’s name through the mud as it goes.

However, from a strictly scientific perspective, we might celebrate all beetles, even Colorado’s state’s spud eating namesake. We have thrown every toxin known to man, including DDT, at the potato beetle and it has developed a resistance to them all. Surely, perseverance should be worth something. This ability to adapt has allowed beetles to fit into every niche imaginable and some we’d rather not imagine. We are indeed fortunate to have a wide variety of beetles evolved to eat carrion and dung. It would be disastrous if they ever went on strike or found career coaches who steered them towards more elegant occupations.

Many varieties have even conquered freshwater. The familiar whirligig beetles amuse us with their seemingly confused circling on a pond’s surface, while a host of predacious diving beetles make their living hunting under the water’s surface. The largest of these, at just an inch or two, regularly eat small fish and frogs. Ranging from the size of a pin head to huge, cumbersome beasts over seven inches, the beetles’ structure is the basically the same.

What distinguishes beetles from other insects are their wings. They have hard wing covers known as elytra that meet down the middle of the body and membranous hindwings that do the flying. That basic design has been tweaked into a vast and often fabulously colorful number of varieties. Metallic greens, golds and iridescent rainbows appear like living gems and in fact have been used as such. Yet the ancient Egyptians are famous for revering an unremarkable, black dung beetle known as a scarab (from the family Scarabaeidae).

The scarab rolls its ball of dung along just as the Egyptian god Khepri rolled out the sun each day. In the case of the dung beetle it then buries the dung ball, laying an egg inside, thus starting an amazing life cycle. That egg turns into a larva (commonly called a grub) then pupae and finally an adult. Even in metamorphosis beetles offer surprises. The California prionus beetle spends several years underground as a grub boring into plant roots and eating sapwood. By contrast, they spend only a few weeks as the large black adult beetle (sometimes over two inches in length) seen flying about during summer. Perhaps we should consider them grubs that go through a beetle phase, rather than the other way around.

One can find the unexpected even amongst those harbingers of warm summer evenings, the fireflies. They are not all sweetness and light. Different species of firefly use different patterns when flashing their lights. These bioluminescent chemical reactions in their abdomen help males and females find one another. However, there is often an impostor lurking during these lovely summer scenes. Some fireflies have learned to mimic the flashing signals of other firefly species, thus luring them in with an invitation to mate. These impostors’ true intentions are far more sinister. Their objective is to lure these other species of fireflies in, and then eat them.

So what then is a gardener to do? For over 300 million years beetles have evolved into their current myriad of shapes, sizes and lifestyles. These unassuming insects are found in every part of our gardens. Their complexity is so stunning as to defy any simple solution for beetle pests. My approach is to try and create a full and complex ecosystem surrounding my gardens and let the natural world sort out some type of balance. Since toxins have proven ineffective, when I feel I must meddle, I do so by simply plucking off and destroying the offending invaders. More often I enjoy seeing their amazing diversity and count their nibblings as a small fee to pay for such an amazing show.

Clearly the beetle deserves our appreciation; they are, in fact, one of Darwin’s superstars of evolution. Perhaps no group of animals has been so successful and yet remained largely unknown. As the resurgent VW Beetle has shown, we humans are suckers for a winning design.

Coleoptera by H. Zell, via Wikimedia Commons

Coleoptera by H. Zell, via Wikimedia Commons

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DB Rudin is a freelance writer, teacher and environmental activist. He is currently the Education Coordinator at Venetucci Farm and Pinello Ranch ( www.venetuccifarm.org ) projects of the Pikes Peak Community Foundation ( www.ppcf.org ). David has been a columnist for Manitou Magazine and, most recently, Greenwoman Magazine. He is an avid birder and also has strong interests in herpetology and entomology. He lives near Garden of the Gods Park with his wife Margaret and their dogs, Gracie and Benny. He can be reached at dbrudin@yahoo.com. His blog, A Naturalist’s Journal, can be found here: https://naturethroughtheseasons.wordpress.com/

DB Rudin with praying mantis

DB Rudin with praying mantis, by Dean Frankmore.