River talk

Five minutes in a milkweed patch

By SCOTT RANDO

Posted 8/26/20

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River talk

Five minutes in a milkweed patch

RR photos by Scott Rando

This is a monarch caterpillar found early in the five-minute milkweed survey. Monarch caterpillars are in their later instars during mid-August, making them large and easy to spot. Monarch caterpillars will only feed on milkweed. When looking for this species, look for eaten leaves that may indicate which plants to check. You may also find another milkweed muncher, the milkweed tussock caterpillar.

RR photos by Scott Rando

The red milkweed beetle (Tetraopes tetrophthalmus) shown here is frequently mistaken for the large milkweed bug (Oncopeltus fasciatus). They are both brightly colored, but the insect pictured here is a beetle, not a bug. Red milkweed beetles are in the long-horned beetle family. It feeds on milkweed using chewing mouthparts rather than by using a proboscis as the milkweed bug does.

RR photos by Scott Rando

The soldier beetle is the only insectivore shown today. It frequents milkweed as well as many other plants, mainly lying in wait for an insect meal. Soldier beetles also eat nectar and do this on milkweed while waiting for insect prey. As adults, soldier beetles appear in July, but are most prominent in August; I spotted many soldier beetles in the milkweed patch.

RR photos by Scott Rando

Oleander aphids, shown here on a milkweed seed pod, are frequently found on milkweed but also use other plants to feed as well. Like all of the insects pictured here, the coloration is distinct, serving as a warning to would-be predators. Like most insects that feed on milkweed, oleander aphids sequester cardiac glycosides found in the sap of milkweed plants, making all these milkweed denizens a distasteful meal.

Posted Wednesday, August 26, 2020 1:02 pm

By SCOTT RANDO

About a week ago, I was getting ready to start the day on an ongoing research project, and temperature and relative humidity are required to be taken and recorded at the start. It takes a few minutes for the instrument to stabilize in order to record accurate values, and after setting the instrument in the shade, I looked around and found a small milkweed patch and decided to see how many critters I could find in the short time I had to wait for the instrument to stabilize.

Right at the start, I found a garden spider, a bumblebee and what looked to be a least skipper butterfly. Intermixed with the milkweed was other plants and wildflowers, which attracted a variety of insects. As the milkweed patch was in a meadow habitat, there were also some grasshoppers and meadow katydids present. It took less than five minutes to observe a dozen insect species.

There were many milkweed-dependent species as well, including monarch caterpillars. These are the ones I included as pictures for this week’s column.