Monthly Mystery #19: Aster Leaf Tubes

As I mentioned here, I normally can’t be bothered with leafrollers, leaftiers, etc.  Not so much because the thousands of leafminers (not to mention gallmakers) in North America are enough to keep me busy for a while as because what I’m most interested in is learning to identify insects by the signs they leave behind.  Leafminers leave such characteristic patterns, and are mostly so host-specific, that they can be identified by the combination of the mine characteristics and the host plant once someone has gone to the trouble of rearing the adult insects.  The leafrollers, -tiers, and -folders, on the other hand, often do not manipulate leaves in a particularly distinctive way, and some of them are extreme generalists, feeding on all sorts of unrelated plants.  So I don’t pay much attention to them until I encounter a recognizable pattern recurring on a particular type of plant.

A year and a half ago in Iowa’s Loess Hills, Julia and I noticed some tied leaves on tall goldenrod (Solidago altissima) that piqued my interest.  On each affected plant, a series of adjacent leaves were tied together and tucked into one another so that they formed a silk-lined tube.

This top view shows the entrance to the tube:

Opening up one of these leaf shelters, we found this larva:

Despite this being a low-resolution and slightly out-of-focus photo, it was sufficient for Terry Harrison to identify it on BugGuide as something in the family Tortricidae. This family is often referred to as the “leafroller moths,” and the larvae of many of the species do roll leaves, but other species do many other things (including mine leaves, form stem galls, feed in flowers, and so on), and many other kinds of moth larvae roll leaves.

I declined to collect any of those larvae, but last week in my backyard I found something similar on smooth aster (Symphyotrichum laeve).

This could well be the same thing as the goldenrod one, even if it is a fairly host-specific moth.  Many insects seem content to feed on both goldenrods and asters, which belong to the same tribe (Astereae).  I found similar leaf tubes the other day on heart-leaved aster (Symphyotrichum cordifolium) in a friend’s driveway.

I now have three of these smooth aster tubes in jars on my desk, so perhaps I’ll be able to post an update eventually with the solution to this mystery.  Incidentally, I’m pretty sure I have last month’s mystery solved, but I’ll wait a bit to see if I get adult moths before posting a follow-up.