In my neighborhood, one harbinger of autumn is the annual visit of Girl Scouts selling their irresistible collection of confections. Who doesn’t love those cookies? Last weekend as I deliberated the pre-purchase nuances between Samoas and Caramel deLites with a Girl Scout mom, her eagle-eyed daughter spotted a gorgeous variegated fritillary caterpillar resting on a violet in my flower bed. This young lady’s Girl Scout vest was replete with badges and awards but surely she deserves the caterpillar-finder-badge, if one exists.
This summer has witnessed a mini-renaissance for caterpillars and butterflies like black swallowtails, painted ladies, and nymphalids we visited in previous episodes. Several years ago I willingly surrendered the battle to maintain a lawn as a monoculture of exotic grasses like fescue or zoysia and as a result, floristically speaking, my yard has become quite diverse. One of the winners in the ground cover competition, particularly in shady spots and landscape beds, are violets. With regularity, I notice significant nibbles and bites at the margins of the omnipresent violets and upon closer inspection several glorious larvae of the variegated fritillary can be found grazing on the leaves. These tiny caterpillars are the spawn of small orange and black butterflies that first appeared in my landscape more than a month ago.
Doesn’t matter whether its violets or pansies, hungry variegated fritillary caterpillars make them disappear.
In northern states the variegated fritillary is a migrant, moving ever northward from its winter redoubts in the Carolinas. Following their arrival in spring, for the remainder of the summer and well into autumn they will be regular visitors to open sunny areas such as fields, pastures, lawns, and along the edges of roads, where females consume pollen and nectar from butterfly weed, milkweed, dogbane, and red clover. When they are ready to lay eggs, females seek nutritious plants such as mayapple, lamb’s ear, purslane, and violets, on which to lay eggs. The caterpillars are gorgeous, bedecked in bright bands of orange and white, further festooned with rows of stout black spines the length of the body. When they have completed several molts fueled by my flowers, caterpillars transition into a beautiful chrysalis before their final pupation to the adult butterfly.
In addition to consuming my volunteer violets, I have discovered several fritillary caterpillars devouring the petals of my pansies. My initial surprise was dispelled after a quick internet search revealed pansies as true members of the violet clan. Variegated fritillaries will be resident and complete several generations over the course of the summer here in Maryland. They are one of the last butterflies active in the landscape well into the fall. As the days grow shorter and the nighttimes chillier, the last of the variegated fritillaries will head south for warmer overwintering grounds or face a chilly death if real winter returns in 2018-19.
‘Caterpillars of North America’ by David Wagner and the Maryland Biodiversity Project were used as references for this episode. Bug of the Week thanks Darcy for spotting the caterpillar and providing the inspiration for this story.
For more information on the variegated fritillary, please visit the following websites: