Tape recorder in hand, he has doggedly recorded the chirps and trills of his six-legged quarry for four decades on five continents, including his native Africa, and would be perfectly happy to keep doing so without public acclaim.
That is starting to get a little difficult.
In the summer, scientists held a three-day symposium in Otte's honor in Canada, after first carefully broaching the idea with his wife, Laurel. Last month the academy awarded him its prestigious Leidy Medal, bestowed only every few years on a prominent naturalist.
"I'm not an awards-type person," he said, his brows wrinkled in mild consternation. "I feel uncomfortable with that kind of stuff."
He quickly added: "It was a great honor."
The numbers are dizzying: 1,500 new species identified, more than 300 papers and books written. And untold thousands of specimens added to the academy's collection of 1.5 million insects from the order Orthoptera (crickets, grasshoppers and katydids). The 70-year-old Swarthmore resident is headed to the Rocky Mountains next summer to gather more.
But to sum up Otte's accomplishments this way is to suggest the value lies in their sheer quantity. Colleagues say the reality is more sophisticated, citing Otte's contributions to the theory of evolution and his ability to discern order in the chaos of life. One example: He theorizes that grasshoppers with African features are found in the Caribbean because their ancestors swarmed partway across the Atlantic and died, creating a bridge of sorts for others to hopscotch their way across the ocean.
And then there's his skill as a scientific illustrator, not just in his own field of research but also on behalf of biologists who study mammals and birds.
"When Dan went to work, he just eclipsed anybody else," said University of Michigan entomologist Richard Alexander, his former teacher and one of the few who rival Otte in his breadth of Orthoptera knowledge. "He's been so many places, more than any of us have been. He's outdone me by a pretty long shot."
The list of exotic places begins with Otte's birthplace, South Africa. The son of a nurse and a Lutheran missionary who taught aspiring African ministers, he grew up in the "bush," in what was then called Zululand. He speaks English, German, Afrikaans, and Zulu. One imagines that his desert-dry sense of humor remains intact in each.
Take the childhood story about how he and some Zulu friends once cobbled together a wagon with old wheelbarrow wheels and went careering down a hillside. The trick was to guide it around a tight turn so they didn't smash into a lemon tree.
"I think there's still DNA on that lemon tree," Otte said.
Otte's interest in biology was piqued in high school when it came time to pick between that and physics and chemistry. For some reason, the teacher who taught the latter two subjects took a dim view of Otte, once calling him "a long slab of misery." So Otte, whose name rhymes with "spotty," picked biology instead.
He went to the United States for college, attending Luther College in Iowa, following a family tradition. He later switched to the University of Michigan, where he met Alexander, who urged him to study grasshoppers. In 1968, the two embarked on a yearlong insect-collecting trip to Australia: crickets at night, grasshoppers by day, sleep from 5 to 11 a.m.
Otte came to the academy in 1975, and now chairs the entomology department. Otte wrote the seminal treatise on the crickets of Hawaii, among other tomes, and his collecting passions have led him from the Pacific islands to the Caribbean.
On one trip to the latter, he was accompanied by academy colleague Robert Peck, who marveled that Otte could identify species from hundreds of yards away by their sound alone.
But it is perhaps when Otte flies back to Africa that he feels most at home - so much so that he used to take along his .22 hunting rifle in an irregular fashion.
Manda Clair Jost, who accompanied him on a March 2001 trip to Africa as a graduate student, learned that Otte wanted to bag a guinea fowl for dinner one night.
So she asked if it was difficult to get permission to take his rifle into the country.
He didn't know. It turned out he had taken apart the weapon and concealed the various components in his luggage - the barrel stashed among his tent poles, for example.
"That was before 9/11," Otte said.
Occasionally the private sector calls upon the scientist for his expertise.
A fast-food chain once hired him to identify the species of grasshopper found in a serving of salad. All that remained were the legs. Another time, a restaurant asked him to look at a cockroach found in a pizza. In both cases, the goal was find out where in the supply chain the unwanted intrusion had occurred.
"Forensic entomology, you know," Otte said.
In August, he's off to the Rockies, probably to Wyoming and Idaho, where he is fascinated by an evolutionary question. On various peaks, different species of flightless grasshoppers live above the tree line - the altitude above which trees do not grow.
The sunlight-loving critters won't go through the dense forest below, so how did they get up there? Either they flew to the mountaintops long ago and later lost their ability to fly, or perhaps they simply walked up during colder periods when the tree line was at a lower altitude, Otte says.
One thing is certain, says the scientist who has already found so much about the world around him:
"We're going to find new things."
Contact staff writer Tom Avril at 215-854-2430 or firstname.lastname@example.org.