SI Vault
John O'Reilly
September 03, 1956
Murder and greed, beauty and song, bright hues and drab, all belong to the teeming world surrounding a
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September 03, 1956

Beetle On The Beach

Murder and greed, beauty and song, bright hues and drab, all belong to the teeming world surrounding a

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The odd but fascinating photograph on the opposite page was taken to John C. Pallister, entomologist at the American Museum of Natural History. Shapely tomatoes, roving eyes, driftwood, sand crabs, empty whisky bottles, howling infants and surf casters are all common to beaches but this seemed to be something out of the ordinary, neither flotsam nor jetsam.

"That," said Mr. Pallister, examining the picture, "is Calosoma scrutator, the green caterpillar hunter. It is a member of the Carabidae, the ground beetle family. It ranges over the entire eastern United States, although in prairie country it tends to be replaced by Calosoma calidum, which is black with golden spots. Frequently it flies over water and drops in. It can stand a lot of submersion.

"This specimen could easily have fallen into the ocean and gotten washed ashore. Or it could have been running around on the sand hunting for food."

He raised a magnifying glass to one eye.

"It seems to have lost one tarsus—no, there it is. But it has lost a part of one antenna. Ordinarily the green caterpillar hunter likes to climb trees for caterpillars. Inchworms are its favorite food. The grubs of this beetle live under leaves, humus and beach drift and prey on other insects.

"Do you find many insects on beaches?" he was asked. Mr. Pallister smiled tolerantly.

"A lively place by day as well as by night," he said. "There is plenty going on. The casual observer wouldn't see much. They're there but you have to look for them."

Leaning back in his swivel chair and locking his hands behind his head, Mr. Pallister proceeded to give an entomologist's version of the seashore. Sometimes it was a grim picture featuring death struggles in the insect world. At other times it was filled with bug song. There was intrigue and there was beauty.

It appears that the beach is a place haunted by insect predators. The great, gray robber flies sit on the sand watching with bulging, expressionless eyes for something to move. When it does, they pounce on it with the fury of a saber-toothed tiger. Robber flies often catch their prey in mid-air. They seize it with their legs, plunge their beaks into it and kill it with a potent injection. They even overwhelm bees, getting them from behind and knocking them out before they have a chance to strike back.

Dragonflies and damsel flies dance in the sunlight above the beach while below them beetles crawl. It may be Calosoma scrutator on the prowl but more likely wandering Colorado potato beetles, lady beetles or weevils. Tiger beetles, some of them greener than emerald, are at home on the beach or near sandy areas. The larva of the tiger beetles has a neat trick for feeding itself. It lurks in a burrow with its head and mandibles just filling the surface opening. When some unsuspecting bug walks over it—whammo!—it snatches the victim in its jaws and retires for a subterranean meal. It also has hooks on its abdomen which lock into the wall of the burrow.

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