In the previous Butterfly Atlas, I found white Turtlehead blooming in early July in a wet area from which several Baltimore Checkerspots emerged. Their caterpillars were also on that plant.This year there was no Turtlehead in that location. However, just last week I found a stand of white Turtlehead in another wet area in full bloom. Isn’t this late for it to bloom? The question is; why would Baltimore Checkerspots use Turtle Head as a host plant in early SEptember when their flight period ends mid-July. I have also seen cultivated pink Turtlehead in full bloom right now. Should Checkerspots be there? I think not.
Anyway, I"m trying to connect Turtlehead with Baltimore Checkerspots but they don’t appear to be synchronized.
Thanks for any comments, Martha Pfeiffer
Hi Martha (no relation 
),
Baltimore Checkerspots (and others in their subfamily) typically overwinter as fourth-instar larvae. Basically, after hatching out this year, the caterpillars eat and grow. After their third instar, the larvae will stop feeding, molt into the fourth instar, enter diapause, and overwinter in the leaf litter. They’ll resume feeding the following year — not only on White Turtlehead, but also Ribwort Plantain, and honeysuckle and ash species if they can find them, before molting finally to pupa and then adult. Hope that helps!
–Bryan
Hey Bryan, do you know if Baltimore Checkerspots also feed on Turtlehead variety with lavender flowers found in most nurseries?
Argh. I’ll confess to not knowing the answer to that. Sorry! Maybe someone else out there does.
Thanks for letting me know. I will ask around.
Also you asked about flowering period for it. If you go here and then put in Vermont for location (top right) the chart will show you phenology from those records that indicate flowering. You can see there are a lot flowering in Sept and even into October. Adding annotations to plants for the stage of phenology is important so we can see this kind of data quickly. White Turtlehead (Chelone glabra) · iNaturalist. The interesting thing about this plant is that the nectar isn’t very palatable to many insects. Leif Richardson did a bunch of work for his dissertation here showing that bumblebees feed on the nectar preferentially when they are sick with gut parasites and it helps them to clear it. They are little ethnobotanists! Of course, larvae checkerspots become unpalatable by sequestering iridoid compounds. Turtlehead is the primary hostplant. The long list of secondary hostplants are likely or mostly used by later instars and in the following spring before they pupate.
Maryland Biodiversity Project [MBP] claims that Red Turtlehead (Chelone obliqua) is not an accepted host plant for this butterfly; only White Turtlehead (Chelone glabra), despite both species being native in Maryland. Pink Turtlehead (Chelone lyonii), is not native in Maryland and presumably would not be an accepted host plant for local populations of this butterfly.