04 June 2015
American Lady butterfly caterpillars construct their homes
When I posted last month about the start of my "fritillary project," I included a photo of a segment of the garden that included a bed of Pearly Everlasting, planted for the Amerian Lady butterflies.
This past week I was out in the garden and noticed that some changes had occurred (see top photo). The uppermost (and most tender) leaves, which are normally surfaced with a delicate downy fuzz, showed evidence of "scrapes," where the surface material had been removed. Near the central stem in this image are a few strands of silk, and some black dots. The latter are tiny bits of "frass," evidence of the presence of caterpillars - though the protagonists themselves were well hidden in the folds of the plant.
I returned yesterday to check the progress and found some elaborate "homes" constructed on the plants:
A small leaf that probably fortuitously happened to overhang another has now been sealed to the second leaf by a network of silk. Bits of the "?epithelium" of the plant have been incorporated into the webwork to create basically a camouflage pattern. But the perpetrator hasn't carried away his/her frass. On another plant I found one of the caterpillars out for an evening stroll:
It's getting to be a pretty good size now. The first instars were teeny and only able to scrape a few cells off the surface of the leaf. This guy is capable of cutting some major defects in the leaves. It is also capable of constructing those "houses" -
This one is bridging the gap between two leaves with silk. I doubt it can pull the leaves together, but it will probably create a canopy over the space (like the area in the upper right) where it can dine at leisure out of the vision of birds and presumably with fewer worries about ants and spiders. Note also that for a still immature caterpillar, this guy has a formidable array of defensive spines encircling its body.
Those in a hurry to see what happens next can peek at one of my old posts about the life cycle of American Lady butterflies (2010 and 2013).