Insect intrigue at Cranberry Lake Park

About a week ago I went on a hike at Cranberry Lake Park sponsored by Six Rivers Regional Land Conservancy and led by Dinosaur Hill Nature Preserve Naturalist Jane Hoyle. The itinerary focused on fall wildflowers – the fall profusion of goldenrods and asters – but I got sidetracked by caterpillars and other insects along the way. Many times I only look at plants, so thanks to the other hikers for pointing out these cool insects! As always, if you think my ID isn’t correct, please let me know!

Caterpillers crawled mostly unnoticed along the trails. When we looked closely, the colors, patterns, and crazy setae (hairlike structures) fascinated us.

American dagger moth caterpillar (Acronicta americana)

American dagger moth caterpillar (Acronicta americana), which feeds on hardwood trees. It often rests in the position shown in the photo, with its head to one side.

Milkweed tussock moth caterpillar (Euchaetes egle).

Milkweed tussock moth caterpillar (Euchaetes egle). Like monarch caterpillars, this species feeds on various species of milkweed and dogbane.

Greenish-yellow Sitochroa Moth (Sitochroa palealis)

Greenish-yellow Sitochroa Moth caterpillar (Sitochroa palealis). This moth is from Europe, but in 2002 was discovered in North America. It feeds on Queen Anne’s Lace, as seen in this picture.

The next thing that caught our attention was a gall on a staghorn sumac. The gall is caused by the sumac gall aphid. The life history of this gall aphid is fascinating: it uses both sumac and moss as hosts. In the spring one female lands on the sumac and lays an egg. From this egg the whole colony of aphids arises clonally! So all of the aphids in the gall are genetically identical. The aphids release compounds that causes sumac to develop the gall. Apparently these galls don’t hurt the sumacs very much. Check out the picture below!

Sumac gall aphid (Melaphis rhois)

Sumac gall aphid (Melaphis rhois). This gall was found on a staghorn sumac (Rhus typhina).

Finally, some clever mimicry. This beetle has coloration that made me look twice. Is it a wasp? Is it a bee? No, it’s a locust borer (probably)!

This beetle looks like a wasp or bee at first glance! It is possibly a locust borer (Megacyllene robiniae). This beetle feeds on black locust trees. There were black locust trees in the vicinity.

This beetle looks like a wasp or bee at first glance! It is possibly a locust borer (Megacyllene robiniae). This beetle feeds on black locust trees, which were in the vicinity.

3 thoughts on “Insect intrigue at Cranberry Lake Park

  1. Jane – thanks so much for leading the hike! The weather, flowers, and insects conspired for a great afternoon. I used “Caterpillars of Eastern North America” (Wagner, 2005) to ID the caterpillars except the Sitochroa moth. I got lucky with some internet searching for that moth and the aphid galls. Probably wouldn’t have notice many of these if you hadn’t slowed us down to look at the goldenrod galls.

    Thanks for the IDs on the goldenrod! Sweet goldenrod (Solidago odora) doesn’t occur in Michigan according to the the online Michigan Flora, and I don’t think I’ve ever seen this species. S. odora keys out near S. ulmifolia and S. rugosa in the Flora of North America. Wonder if we were looking at one of these?

    I usually record my bird observations on eBird ( and observations of plants, insects, fungi, and other organisms on iNaturalist ( I often have a camera more handy than a notebook, so this seems to work for me. I’d love to get regular observations of flowering in a few parks!

  2. Good work on the caterpillars and gall, Ben. Do you keep a record of plants and “animals” found where and when? I had just a big book way back when there was no computer and had a page for a date to record what we found each year on that date. First blooming of trillium etc. It was fun to look back on it. But of course, that was for only one little preserve, Dinosaur Hill.

    Three goldenrods I think I identified Sept. 14 were;

    1. sweet goldenrod, leaves anis scented, leaves growing upward, lots of leaves

    2. lance leaved goldenrod, leaves 5 veined

    3. showy goldenrod, stem reddish, lower leaves large, egg shaped or oval

    I know you know these but they can be very confusing and Ed Voss says they hybridize. Ha!

    Jane Hoyle

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