On a clear August morning in southeastern Pennsylvania, more than a dozen adults and children stood in a park pavilion, listening to mealworms sizzling in a hot pan. They were learning about entomophagy — the human consumption of insects — from Lisa Sanchez, a naturalist with the Lancaster County Department of Parks and Recreation, who has taught the practice for 25 years. Suddenly, one mealworm sputtered out of the pan. Six-year-old Adaline Welk — without prompting — popped it into her mouth. The crowd cheered for the newly minted entomophagist. “It’s not that bad!” she exclaimed. “It kind of tastes...