Monday, December 3, 2012

Monday Moth: Beautiful Plumage, but pesky

Ash Leaf Coneroller Caloptilia fraxinella (Ely, 1915) 
While most insects that overwinter as adults hide outside, some are rude enough to invade our homes. This is a bit dangerous for the bugs - most homes are a bit too warm for sleeping the long winter away and they run the risk of waking up, fluttering around, and running out of food reserves - or being squashed. That's what happened to one of these tiny moths that I found fluttering around the coffee pot this weekend. I suppose that was a bit mean-spirited, but the Ash Leaf Cone-roller Caloptilia fraxinella (Ely, 1915) isn't one of my favourite insects; and besides, I hadn't had my coffee yet. 
A small, slender moth with this distinctive stance is probably a Blotch Leaf Miner 
Caloptilia Hübner 1825 seems to be from the Greek kalos  (=beautiful) and ptilos (=plumage). Well, I suppose beauty is in the eye of the beholder and Jacob Hübner was fascinated by butterflies and moths. The species name refers to the genus of the ash tree Fraxinus, Latin for an ash tree. Confusingly, Latin words that end in '-us' are usually masculine, but in the case of plants, usually feminine. This may be because trees and shrubs were thought to be the abodes of dryads - female spirits that lived in woody plants. In any case, our street is lined mostly with Green Ash (Fraxinus pennsylvanica) and American Elm (Ulmus americana).
Gracillaria syringella (Fabricius, 1794) - Lilac Leaf Miner
 Ash Leaf Cone-rollers belong to the family Gracillariidae - with about 300 North American species of tiny moths whose caterpillars make blotch mines in the leaves of plants. Before 1999, Ash Leaf Cone-rollers were not endemic to Edmonton, but somehow they jumped across the prairie from the East and began infesting our boulevard ash trees. The adults emerge from hibernation in the spring and lay eggs on the newly emerged ash leaves. The early instar caterpillars mine their way between the top and bottom of the leaflets making discoloured blotches. This is unsightly, but not especially damaging to a healthy tree. But then, around the beginning of June, the little green worms emerge from their blotches and dangle down on strands of silk. Their goal is to find a new leaflet to roll and tie into a cone so they can complete their development. Unfortunately for us, a significant number of them dangle from the boulevard trees and become entangled in our hair and squashed on our clothing as we walk down the streets. Most people find this very icky, and some have handwaving fits, but mostly I just try not to walk under the ash trees.

1 comment:

  1. Some of them really do have beautiful plumage though. I wonder what the type species (C. upupaepennella) looks like. There's a Caloptilia I've seen at lights a couple of times that is iridescent purple with yellow spots. Pretty fancy.