This week at Crossroads at Big Creek, we focus on and celebrate insects, which may seem strange to some folks who spend much of their time and money trying to eliminate them.

And I get that, sort of. Agricultural pests can be devastating. I’m currently battling Japanese beetles on my raspberries, and I try to avoid stepping on yellow jackets. But scientists tell us that of the millions of known species of insects, only about 10,000–30,000 are considered harmful. Put another way, a mere 1% of insects bite, sting, or spread diseases to humans. If you add forest and agricultural pests, maybe 3% of all insects are harmful.

That means the vast majority of insects are beneficial—as pollinators, decomposers, or vital links in the food chain … essential to life on Earth as we know it. And the rest are neutral, not helpful or harmful to humans or plants.

Gall-forming insects, which we’ll study during our Saturday Science family program on September 13 seem to fall into that neutral category—but they are particularly peculiar and fascinating. Take a walk this time of year, and you can’t help but notice that some leaves are covered with lumps, bumps, or spiky clusters.

For example, willows may have growths that look like pinecones; aspen trees can show abnormal swollen lumps that resemble “already-been-chewed bubblegum”; and especially obvious in late summer are the round balls that form on Canada goldenrod stems. Plus literally hundreds more. Galls!

Galls develop when an insect lays an egg on a plant's leaf, stem, or bud. When the egg hatches, the tiny larva secretes a chemical—technically not a hormone, but a hormone-like substance—that triggers the plant to produce extra cells, enlarge those cells, and direct extra sugars to the sturdy structure around the larva.

A gall is the perfect nursery. It hides and protects the larva from predators, shelters it from the weather [think climate-controlled comfort], and provides an unlimited supply of nutritious food until the larva pupates and eventually emerges as an adult insect.

During Saturday Science, participants will learn about various local galls—maybe even dissect a few-- and then venture into the preserve to find examples.

At our Tuesday after-school program, Environmental Exploration, families will explore Big Creek in the fall—when the water is quite low—giving young explorers a chance to search for aquatic insects that take refuge in the moist mud under the rocks.

Wednesday marks the kickoff of the Fall Session of Junior Nature Club. Preschool children and their adult companions will walk to the North Bridge. Because these young learners are fascinated by ants, grasshoppers, and anything that flies, our first gathering will undoubtedly become an insect adventure.

Thanks to our donors' generosity, Crossroads can provide free educational opportunities to learners of all ages. Our trails are also open all day, every day, free of charge.

Saturday, September 13

2:00 Science Saturday: Galls!

This program is intended for school-aged children, but learners of all ages are welcome. Discover insect galls in the lab, then head outdoors for a scavenger hike. Meet at the Collins Learning Center. Registration not required. Free and open to the public.

Tuesday, September 16

3:30 Environmental Exploration – Under Rocks

When Big Creek is no longer “big,” insects and other aquatic creatures lurk beneath the rocks. This outdoor adventure is geared toward elementary students, but learners of all ages are welcome. Meet at the Collins Learning Center, Crossroads, 2041 Michigan Street, Sturgeon Bay, Wisconsin.

Wednesday, September 17

10:00Junior Nature Club

This family program is for children aged 3-5, but parents or guardians are expected to remain with the group throughout each class. Siblings and family members are welcome to participate. All should come dressed for outdoor exploration. If the weather is too bad to be outdoors, we will do nature-related activities inside. No reservations needed. Meet at the Collins Learning Center, Crossroads, 2041 Michigan St., Sturgeon Bay.

1:30 Wandering Wednesday

Join this naturalist-led hike through Crossroads's trails. It is an easy walk and will take about an hour. It is free and open to all ages. Meet at the Collins Learning Center, Crossroads, 2041 Michigan St., Sturgeon Bay.