Monday, June 20, 2011

Highlights from East Brunswick's Moth Night

Mothing at home can be fun and productive. It has the added benefit of being convenient to set up and take down, and proximity to the house makes it possible to take breaks if the action is slow. Still, it is interesting to see what a UV light will produce in a different habitat, especially a more natural one. So, last Friday, I went with Anita to participate in East Brunswick's annual moth night. I had been to one two years ago with Patrick, and that helped get me started with nocturnal mothing.

This year's event was at Keystone Park instead of the Butterfly Park. The main differences in mothing at the two sites are that Keystone Park is closer to the South River, so it offers a greater chance for species characteristic of wetland environments, but it lacks butterfly gardens, so there would not be much a chance to watch moths nectaring at flowers. The event uses a bright mercury vapor lamp set in front of a white sheet. Mercury vapor lamps shine into the UV part of the spectrum, which attracts more moths than a normal incandescent or CFL bulb would. Trees along a short trail through the woods were painted with a sugary paste made from brown sugar, stale beer, and other ingredients. The two methods are intended to attract different types of moths; some are attracted to light but not to sugar (in some cases because they lack mouthparts) or to sugar but not light.

The light attracted quite a lot of moths, some of which I never really got to see because the area in front of the sheet was crowded at times. One of the first moths I saw was the Dimorphic Macalla Moth (Macalla superatalis) shown above. From a distance, it does not look like much, but up close you can see the vivid green and rusty stripes on its forewings.

One of the larger moths at the sheet was this tussock moth. It may be one of two species, Banded Tussock Moth (Halysidota tessellaris) or Sycamore Tussock Moth (Halysidota harrisii). Based on subtle differences in their costal patterns (the costa is the leading edge of the forewing), I think this is a Banded Tussock Moth, but I could be persuaded otherwise.

Several geometer moths visited the mercury vapor lamp, including a few that are familiar to me from mothing at home. One of the more interesting geometers was this gray moth. Its markings are so indistinct that it still leaves me a little uncertain. I think it may be a Canadian Melanolophia (Melanolophia canadaria). Among other things, moths of that species feature a noticeable flying gull shape at the trailing edge of the forewing; that marking is clearly visible in this photo. The moth is joined by two other insects, the topmost of which is a Ptilodactyla beetle.

One other notable moth on the sheet was this crambid moth, called a Checkered Apogeshna (Apogeshna stenialis). Micromoths can seem at times like an army of drab, tiny creatures that are barely distinguishable from each other, but some micromoths are quite intricately patterned like this one.

This was my first sighting of a plume moth. I think this one may be Himmelman's Plume Moth (Geina tenuidactylus).

The sugared trees were mainly attended by isopods and wood roaches, with relatively few moths taking advantage of the opportunity for a snack. One walk back along the trail, however, yielded the moth of the night. Anita was the one who found it, a large Ilia Underwing (Catocala ilia) sipping at the moth sugar. The moth kept its forewings spread open, so that it was possible to see and appreciate the orange and black hindwings that give this and other Catocala moths their name. While I have seen other moths named "underwing" before, I think this is my first sighting of a true underwing in the genus Catocala.

When it tired of our flashlights and cameras, the underwing flushed and tried to hide under a nearby leaf. This was not an effective hiding place for a large moth with bright orange wings.

Before the evening ended, this sphinx moth landed on the back side of the mothing sheet. While its eyespots are somewhat hidden in this view, there is enough detail visible to mark it as a Small-eyed Sphinx (Paonias myops). The eyespots and bright hindwings, normally hidden from view, can be displayed to baffle or confuse predators just enough for a moth to escape (mostly) intact. Not all sphinx moths have such clear eyespots as this one does.