Flashes and Wings in Riverbend Park

A Year of Field Tests in Riverbend Park

1Riverbend Park sits along a river in the middle of a busy city. Its naturalist, Dr. Imani Mwangi, runs a science club for middle schoolers. This year the club, including sixth grader Selin Aydin, studied how park plants and animals produce offspring.

2In spring the club noticed two kinds of trees in bloom. The oaks had long, dangling flower clusters called catkins, with no colorful petals or nectar. On windy days the catkins shed clouds of yellow pollen, and sticky slides the club hung nearby were soon dotted with grains. A crabapple tree near the gate had pink petals and a sweet scent, and bees moved from flower to flower all afternoon.

3On summer evenings, male fireflies of one common species drifted over the lawn, each flashing yellow-green light in a short pattern. Females waited in the grass. Dr. Mwangi explained that when a female flashes back, a male often flies down to her. To test whether the pattern matters, the club used a small penlight covered with green film. Each time the club found a female sitting in the grass, a student stood 1 m away and flashed one of three patterns for 30 seconds without touching her. Pattern A copied the flashes of the males on the lawn. All tests used the same penlight between 9:00 and 10:00 p.m. They counted how many tries got a flash in reply.

4In the fall the club studied seeds. Maple seeds have a thin, papery wing. Milkweed seeds have a tuft of silky threads. From a platform 2.0 m above the ground, students dropped 10 winged maple seeds, 10 maple seeds whose wings they had carefully torn off by hand, and 10 milkweed seeds with tufts, one at a time. A box fan on its lowest setting made the same gentle breeze for every drop. The students timed each fall and measured how far from the spot below the platform each seed landed, then found the averages.