Tuesday, June 23, 2009

Botanical Detectives: Case of the Mysterious Caterpillar

A recent visit to Davis Memorial, a DNAP preserve in Adams County, offered some fine views of many rare and unusual plants, and I hope to cover some of them in the near future. But today's blog focuses on a mystery caterpillar and the way botanical clues can be used to discover its identity.

A prickly looking beasty, isn't it? Sometimes those "stingers" pack a wallop- so my policy is not to touch the scary looking ones. Get Janet to do it!

The best guide for sorting caterpillars is Wagner's, if you don't have it- get it. Even a novice can sort "cats" by these incredible photos. Once you have a little experience you'll know which group to head for, straight away. And learn to rely on the botanical hints in the back of the book. Your caterpillar is on Milkweed? Could be a Monarch or a Tussock Moth.

Our botany, which appeared to be a mint, did not provide a very good clue. Since this caterpillar was quite large- probably last instar- he could be on the walkabout many take just prior to metamorphosis. Don't jump to hasty conclusions, chrysalises are often found on something other than the host plant.

Our mystery solved: The caterpillar's appearance, along with the host plant in the area, plus its preferred location of a swampy area next to a steam, all add up to this beautiful creature.

Photo by John Howard

Look closely- this is not a Pearl Crescent, but rather a Silvery Checkerspot. Sightly larger than the crescent, look for that "open" white spot on the lower wing. This Southern Ohio specialty is being seen more frequently towards the north, and it makes me appreciate the common host plant Wingstem, Verbesina alternafolia just a little bit more!


  1. Interesting stuff. Here in the UK the caterpillar of our fairly common yet beautiful Small Tortoiseshell Aglais urticae feeds on stinging nettles Urtica dioica. Every time I get stung I remind myself of this..

  2. Our Milbert's Tortoiseshell feeds on nettles too! We have some growing in the butterfly garden at Byers Woods- and I think it drives the gardeners nuts! But we have Milbert's :)

  3. Yikes it does look scary..Thanks for the book tip..and all good info on this catip