Not including animals like the bald eagle or Eastern bluebird, the monarch butterflies have garnered much interest in people.

This beautiful insect with a 3½-inch to 4-inch wingspan has seen its numbers drop. The major reasons are the loss of their wintering habitat in Mexico and, in particular, fewer fields, meadows or roadsides with their necessary food. That food is the common milkweed.

Monarch butterflies lay their eggs on milkweed plants, and it is the only food the caterpillars eat. It appears that many folks have taken on the challenge and either keep milkweed plants growing where they normally would have cut the “weeds down,” or even purchased seeds and planted milkweed in their flower gardens. (You may be more successful digging out the plant’s underground rhizomes and planting them rather than the seeds.)

Common milkweed (Asclepias syriaca) is found growing from southern Canada and throughout most of the U.S. east of the Rocky Mountains. It does not survive well or grow in areas that are very dry.

Swamp milkweed is another milkweed species and ranks second in their food preference. Keep in mind that the female monarch butterfly chooses where to lay her eggs because that is where the caterpillars will hatch and begin feeding. If she chose another plant species to lay her eggs, they would not find the proper food and not survive. I notice that most of the milkweed plants grow taller (3 to 5 feet) than the other meadow plants, and I surmise it is the plants’ way of attracting pollinators to their pinkish/purplish flowers.

The milkweed plant is not just a great host for the monarch butterflies. About a month ago I spent an hour or two observing and photographing all the other insect activity in a large milkweed patch. They don’t host only insects but a number of spider (arachnid) species, too.

In this week’s column I’ll attempt to show you some of those that depend on milkweed and the interactions between them. Please note that the milkweeds’ leaves and stems contain toxins called cardiac glycosides, and when insects ingest that, the toxin remains in them as larvae, nymphs and adults. Those insects that feed on milkweed are almost all brightly colored, not making the same attempt as other insects to blend in, but to advertise their toxic qualities.

See if you have observed some of these “critters” already. If not, there is still time as summer wanes to find a few, so get out there …

Referring back to last week’s article on hummingbirds, Test Your Outdoor Knowledge: Which ruby-throated hummingbirds live the longest, males or females?

Last Week’s Trivia Answer: It may surprise you, but as you read this week’s column, most of the male hummingbirds have already left our region. Females and young of the year generally migrate weeks later.

Email Barry Reed at breed71@gmail.com