A Johns Hopkins University researcher’s work into the bioluminescence of lightning bugs from the 1940s to the 1960s gave thousands of Baltimore and Maryland youngsters not only joy, but a little extra money, too.
The tiny, graceful creatures with their greenish-yellow light, who seemingly perform aerial ballets while seeking mates, are as much a part of a humid Maryland summer evening as steamed crabs, a cold National Bohemian beer, corn on the cob, an on-fire ripe Eastern Shore tomato, the jingling bells of the Good Humor man or the sounds of an Orioles game emanating from a radio or TV.
It was Dr. William D. McElroy, one of the world’s leading experts in bioluminescence at the time, who conducted his research in Room 113 of Mergenthaler Hall on the Johns Hopkins University’s Homewood campus. That was where his youthful net-carrying army was instructed to bring their harvest.
As night came on and the fireflies took to the air, platoons of youngsters began zigzagging across yards and fields in joyous pursuit of the flickering insects.
McElroy discovered that the gentle insect’s flash was the result of an enzymatic reaction with the compound ATP, or adenosine triphosphate, which was an essential component of the mating ritual. This made him world-renowned, and a much-sought-after expert until his death in 1999.
“This was a period of basic science,” J. Woodland Hastings, a Harvard biologist who worked with McElroy, told The New York Times at the time of his death. “They were not only an example, but a leading example, and they were available, especially in Baltimore.”
He came to Hopkins in 1946 and from 1956 to 1969 was chairman of the biology department, where his research centered on how fireflies convert chemical energy into light, at a time when little was known about them.
In 1947, McElroy organized his first meeting of schoolchildren, and to stimulate their hunt offered a bounty of 25 cents for every 100 lightning bugs brought to Mergenthaler Hall, and to stimulate them in their work, offered a $10 prize to the kid who brought in the most bugs. That would be worth over $100 today.
At the end of the first “season,” which began in June and ended in mid-August, it was Morgan Buchner Jr., 10, of Hadley Square in Guilford, who scooped up the $10 reward.
The first season netted some 40,000 fireflies, which McElroy carefully put away in his laboratory — frozen for later experiments or immediately dissected. In 1952, a 14-year-old boy single-handedly collected 37,000 of them.
“Life in Baltimore, for the fireflies, became a chancy, precious thing. … The result of this was a mass attack on the firefly population in Baltimore and indeed, in such outlandish places as Long Island, New York; Ohio, Pennsylvania and Delaware. A newspaper in Indianapolis offered to alert the youth of Indiana,” reported The Evening Sun.
In good years, it wasn’t uncommon for McElroy’s Baltimore army to net 500,000 lightning bugs, with supplies reaching 1 million a year by the 1960s. This caused alarm over what was one of the most potent components defining a summer’s evening was quite possibly in peril of disappearing.
“Some people have complained that our collections might cut deeply into the firefly population, but the flies we’re are collecting are males,” McElroy, who had earned the sobriquet of “firefly man,” told The Sun in a 1965 interview. “The females stay in the grass and lay eggs, so our collection should have no effect on population.”
While in Baltimore, McElroy served on the Baltimore school board and was chairman of the board of trustees of Baltimore Junior College.
He left Hopkins in 1969 when he became head of the National Science Foundation and later chancellor of the University of California at San Diego.
Reflecting on his life in science and particularly his research with lightning bugs, McElroy said in an interview, “Quite frankly, that was the most fun I ever had in my life.”
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“Dr. McElroy has made valuable contributions to science, including the discovery that the process by which some creatures make their own natural light is closely related to the process by which all animals convert chemical energy into mechanical energy,” The New York Times mused at the time of his death.