The birds and the bees.

Dr. Jerry Freilich is quick to confess that he is quite interested in the birds and the bees, and he’s confident that everyone else is, too.

The birds are fascinating, of course, but it’s the bees he really wants to talk about.

“Biodiversity Begins with a Bee” will be the topic when Dr. Freilich speaks at The Belfry on Tuesday, October 22, for the second lecture in the 2019-2020 Frontiers in Science series.

Most people can name fewer than five kinds of bees and are astounded to learn that there are actually 4,000 native bee species in the United States. Most of these are tiny, fast-flying, and hard-to-spot despite their vital importance to our lives. Dr. Freilich’s three-dimensional images and 3-D glasses for the audience will provide a valuable tutorial about native bees and the role they play in sustaining the biodiversity around us.

“We have a general understanding that living things create the oxygen we breathe, clean the water we drink, and provide every molecule of food we eat,” Dr. Freilich explains. “Yet we have only the vaguest notion of the species that provide these services.”

The term “ecosystem services” describes the benefits that humans receive from properly functioning ecosystems, such as plant pollination. Scientists estimate that every third bite of food we eat depends on pollinators such as bees, which pollinate about 75 percent of farm crops worldwide every year.

“As the human population of the earth doubles and triples, our natural support system is stressed,” Dr. Freilich says.

Understanding how pollution, urbanization and a changing climate threaten the connections in the natural world that keep humans fed and thriving is paramount, he says. That understanding can begin with the study of bees as we explore a microcosm of the larger world of biodiversity that sustains us.

Dr. Freilich is an entomologist who recently retired as Olympic National Park’s research coordinator, where one of his projects was to find and identify as many bee species as possible in the park.

At the invitation of Sisters Elementary School principal Joan Warburg, he will also visit several third-grade classrooms — with bugs and microscopes at hand — during the afternoon.

Dr. Freilich’s evening lecture, sponsored by the Sisters Science Club, starts at 7 p.m. at The Belfry.

Social hour begins at 6 p.m. with light fare, beer, and wine available. Admission is $5; teachers and students are admitted free. The Belfry is located at 302 E. Main Ave.

For more information on this topic and on the Sisters Science Club: www.sisters

scienceclub.org; sciencein

sisters@gmail.com.