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Q: A single bat has been living in the screened porch of our cabin. We have a bat shelter nearby, but the bat doesn’t seem to be using it. Before we close the gaps near the roof, how can we provide an alternative shelter and relocate the bat without harming it?

People commonly encounter single bats during late August and early September. This is likely a combination of two factors: juvenile individuals starting to explore the landscape and the general bat population entering its transition period into winter.

In terms of best practices, conservationists ask people to be patient during this time of year and wait three to four weeks before doing anything. These small mammals are not looking for permanent residences at this time, and so there shouldn’t be a large concern about one or two bats showing up. The issue should resolve itself in a short period of time.

Sometimes, individual bats may accidentally enter a home through an open door or window or drop down a chimney. If this occurs, you can learn how to catch and release a single bat at batcon.org/about-bats/bats-in-homes-buildings.

Q: What kind of spider is this, and what is the purpose of the zigzag pattern?

This is a female black-and-yellow garden spider (Argiope aurantia).

The zigzag design, called a stabilimentum, helps reinforce the web. Females make vertical zigzag bands above and below the middle of the web; juveniles make circular stabilimenta in the center. The purpose, and the design, is not completely understood. It may work as camouflage for the spider lurking head-down in the center. But it also may warn birds of a hard-to-see web or attract insect prey. When prey are caught, the spider may undulate or vibrate the web to further ensnare its victims.

This species has a large range — it can be found from Canada to Costa Rica and throughout most of the temperate United States.

Missourians are most likely to see this spider in the late summer and fall, when large females construct magnificent webs in gardens, fields, along the eaves of houses, outbuildings, or anywhere they can anchor a thread. Males often build smaller zigzag webs nearby. Webs tend to be rebuilt in the same place throughout the summer. Each night the spider eats the web’s circular interior and rebuilds it the next morning.

Appreciated by gardeners, these spiders eat a variety of insect pests. They are not aggressive. If handled, a spider might be goaded to defend itself, but its bite is similar to a bee sting.