We’re back to testing your ecological knowledge this week with another host plant question!
Which of the following butterflies uses the plant on the left as their host plant?
Can you name the host plant in the comments? Remember to use the spoilers tag!
aster, sorry don’t know what spoiler tags are.
Correct! This is a flat-topped aster. The spoiler tags can be found in the menu of the gear symbol on your toolbar (pictured below).
You can also use them by adding [spoiler] ahead of the text and [*/spoiler] (without the asterisk) after the text.
Click below to reveal the answer to this weeks’ quiz!
The plant on the left is a flat-topped aster, the host plant of Harris’ checkerspot, top. The atlantis fritillary, below, feeds on various species of violets.
The flat-topped aster looks like an umbrella of singular white flowers, which earns it its other name - parasol flat-top. If you look closely at the yellow center you will see that it isn’t one big flower but a composite flower made up of many tiny yellow flowers. Flat-topped aster live in moist places, including the edges of swamps. In Vermont, you can find its’ whorled leaves beginning to grow in May and the flower blooms from July to early fall.
Harris’ checkerspot caterpillars emerge from aestivation in May and feed until they pupate and turn into adults in late May - June. That generations’ eggs will hatch into a new batch of caterpillars in July and feed communally while protected by silk webs. As voracious herbivores, they often defoliate their host and can suffer high mortality rates if they cannot crawl their way to another host plant in time. They have been found across most of Vermont.
Fritillaries exclusively eat violets. Females lay their eggs in the leaf litter where violets grow. The caterpillars hatch in the fall and overwinter without eating until spring when violets emerge as a spring ephemeral. Keep an eye out for these spiky caterpillars munching away at delicate violet leaves in May!
Photo credits
Flat Topped White Aster by Ian Whyte (iNaturalist)
Harris’ Checkerspot by Jeff Cherry (iNaturalist)
Atlantis Fritillary by Bruce Cook (iNaturalist)
Harris’ checkerspot information from:
Dethier VG (1959) Food-plant distribution and density and larval dispersal as factors affecting insect populations. The Canadian Entomologist, 91, pp. 581–596
Merchant, T.K. and Morse, D.H., 2024. Where do Harris’ Checkerspots Lay their Eggs and what are the Consequences? Journal of Insect Behavior, 37(2), pp.121-132.
Ready to check out this weeks’ quiz? Click here!
