Tuliptree Leafminer

Eleven years ago I dug up a less than knee-high tuliptree (Liriodendron tulipifera) sapling from my friend’s yard in southern Connecticut and planted it in my parents’ front yard in Pelham, Massachusetts.  I live near this tree’s northern range limit, and I was unfamiliar with it before that summer, which I spent doing plant surveys all over Connecticut.  Eight years later I was learning about leaf mines for Tracks & Sign of Insects, and when I discovered there was a species of moth, Phyllocnistis liriodendronella, that mines in the leaves of this tree, I checked the leaves of my tree and found the mines right away.  I was impressed that the tiny moths had found this tree: as far as I know, the closest tuliptree is a street tree in downtown Amherst, over three miles away, and the closest place I have seen it growing in the woods is in Florence, about fourteen miles away.  My tree is now about twenty feet tall, and I have seen the mines on its leaves every year since then. On June 17 of this year I decided to collect two mined leaves.  The mines are long and linear as in all Phyllocnistis mines, but are unusual in that they are sometimes on the underside as well as on the upper leaf surface.  Some of this year’s mines were formed so early in the leaves’ development that the leaf edges are crinkled and distorted with some dead tissue.

Mine of Phyllocnistis liriodendronella in a tuliptree leaf.

On June 30, the same day that the sycamore moth emerged, I found a tiny parasitoid wasp in the bag with the tuliptree leaves.  I put the bag in the fridge overnight, and when I took it out in the morning to photograph the wasp I discovered that there were in fact three of them, as well as one moth.

One of two female eulophids that emerged from the Phyllocnistis liriodendronella mines.

The male, with fancy antlerlike antennae.

Adult Phyllocnistis liriodendronella (3 mm).

It appears that there are no previous records of parasitoids from Phyllocnistis liriodendronella–I checked the Universal Chalcidoidea Database (Chalcidoidea being the superfamily that includes the eulophid wasps shown above), and there is no mention of any parasitoids on the P. liriodendronella page of the Global Taxonomic Database of Gracillariidae (Gracillariidae being the family that includes Phyllocnistis).  It also appears that this is the first online image of an adult P. liriodendronella.  According to the Phyllocnistis page at microleps.org, other than P. insignis (which I wrote about here), the moths in this genus all look about like this:

The “white” Phyllocnistis species (i.e., those other than P. insignis) are so similar in appearance (and even in genital morphology) that rearing is the only means by which to collect definitively-identifiable representatives.”

I see significant differences between the moth pictured above and the P. vitifoliella pictured at microleps.org, but I don’t know how consistent these might be.  This statement makes me wonder how I would tell whether the mines in my mother’s nearby magnolia bush are made by this species or P. magnoliella, since based on the Global Taxonomic Database of Gracillariidae both of these species can mine in magnolia–although all but one of the references for this were written before P. magnoliella was described, so I suppose these are suspect.  Anyway, speaking of P. vitifoliella, a few weeks ago I collected some grape leaves containing mines of this species, and today I got photos of two eulophids that emerged.  P. vitifoliella, like P. liriodendronella, appears to have no previously documented parasitoids.

Eulophid parasitoid of Phyllocnistis vitifoliella (1.2 mm).

Added 12/11/2012: Eulophid specialist Christer Hansson tells me the P. liriodendronella parasitoids shown here are a male and female Pnigalio, and the P. vitifoliella parasitoid is a Closterocerus.