|A Baltimore Checkerspot Butterfly nectars on Indian Hemp|
We've had our first good Baltimore Checkerspot season in at least 5 years. Lately They've been spotted in various meadows around the nature preserve. Its interesting how some species, like the Baltimore, can become so rare even though their available food supply (larval food plants) varies so little year to year. Turtlehead is the traditional food plant for the species and it has only expanded in the past 12 years - both on its own and due to our restoration efforts.
|Turtlehead is the traditional host plant of the Baltimore Checkerspot|
|Turtlehead occurs in wet meadows and along stream sides|
The Baltimore also utilizes English Plantain as an adopted food plant. This alien weed is ubiquitous in fallow fields, suburban yards and so called "waste places". Though the ability to feed on such a prevalent plant could only be considered as good news, it still has not resulted in making the checkerspot very common.
|The Baltimore is one of our most distinctive butterfly speices|
|Baltimores mating in one of the upland meadows|
With the ability to inhabit both low land swamps (the domain of turtlehead) and dry upland fields (where plantain often dominates), the Baltimore may be encountered in a range of diverse habitat settings. At the preserve, it has been the wetlands where they occur most reliably - and when the population contracts, it's most often the wetlands that hold the last remnant of the population.
|A female Checkerspot with its abdomen swollen with eggs|
|The female lays her eggs on the underside of the Turtlehead leaf|
|The eggs are yellow or orange and are laid in a large cluster|
Essentially, Baltimore Checkerspot Butterflies are tent caterpillars. Oh no! Not dreaded tent caterpillars. Unlike the Eastern Tent Caterpillars and the Forest Tent Caterpillars, the checkerspots do not defoliate forests. They make their tents around their perennial foodplants and have no reason to ascend into the trees.
Unlike most butterfly species that deposit their eggs individually
on their host plants, Checkerspots lay large clusters of eggs on a single leaf.
The young caterpillars feed together and collectively spin a large silk tent
around the host plant. The tent offers them some degree of protection from
predators - at least during the early period of their development. Ichneumon
wasps patrol the outside of the tent and search for outliers that they can
reach with their ovipositors and attempt to parasitize. When does a
checkerspot caterpillar appear to
metamorphosize into a wasp? That's after its had an ichneumon egg laid inside
Later instars of the checkerspot caterpillars are more independent
and they feed without the protection of the tent. Their larval skins are
covered with hairs which make them unpalatable to most birds and other
predators. Baltimore chrysalises are small structures, but they are colorful and well bejeweled. Certainly it's a fitting packaging for one of our gaudiest butterflies.
I was watching several Checkerspots as they raced around the meadow. Males were chasing off other males while females were scouting for their host plants. Some females had noticeably swollen abdomens and were presumably full of eggs, but the one that I followed appeared to be empty. She kept landing on turtlehead leaves, but although she went through the motions of laying, nothing was being deposited on the leaves.
|The silk tent is woven around the Turtlehead plants|
|The early instar of the Baltimore larvae create the tent|
|These caterpillars are now large enough to live outside of the tent|
|The Baltimore caterpillar starts to shed its final larval skin|
|The ornate chrysalis of the Baltimore Checkerspot|
|Note the orange antenna clubs, eyes and legs|
|An explosion of orange - the Baltimore nectars on Butterflyweed|
|Nectaring on Valrian flowers|