The bagworm- it builds a house and comes to eat your plants

I came across an old acquaintance today while walking near Arcadia,FL, the bagworm. This curious caterpillar of a moth with an unpronounceable name, Thyridopteryx ephemeraeformis, has a very strange habit that makes it very distinctive and easy to identify. As its name implies it makes a case or bag out of silk and bits of plant material and crawls around with only its head and front end exposed. The bag is an ingenious contraption of small pieces of stems and leaves of the plant that the caterpillar is feeding on. In this case the plant was a hog plum, but this moth feeds on a wide variety of plants, causing it to be a serious pest in some situations. Clearly the bag serves to protect the caterpillar in two ways; it is both a camouflage and a physical protection against attack by predators such as birds. However the caterpillar must come at least partly out to feed and can be attacked then.

For some amazing photographs of the Bagworm check out Victor Engel's work: http://bugguide.net/node/view/135982/bgimage

The breeding habits of the bagworm are quite peculiar- the female is flightless and remains in the case for her entire adult life. The adult male must fly to her location and fertilize her eggs, which are laid in the bag where they remain all Winter. They hatch in the Spring and the young larvae disperse and make their first bags. Although this species is named for a mayfly (which the adult male slightly resembles), there is a greater resemblance to the caddisfly larvae which lives in water but also constructs a case out of sticks, sand or small pebbles. Now although caddisflies and bagworms are somewhat related, they are in separate groups and it seems unlikely that a common ancestor had the habit of constructing larval cases. So we may conclude that their shared habit of constructing cases for their larvae is probably an example of separate but convergent evolution.

So if you see bagworms on one of your valued plants you might just want to move them someplace else since they can do some serious damage. The simplest time to do this is in Winter when the bags contain hundreds of eggs and can easily be picked off the plants. But in any event let us marvel once again at the remarkable diversity of nature.


Bill Dunson
Englewood, FL & Galax, VA

Snake plant flowers

It is hard to believe that anyone has not at some time had snake plants (Sansevieria) in their family households. The ability of this interesting but strange plant to survive almost any treatment made it popular around the world as a house plant. Unfortunately in warmer areas such as Florida they ended up planted outside and have caused considerable problems since they are highly invasive, especially in shaded forest locations where native plants are crowded out by the snake plant. Removing them is problematic since the roots break into small pieces and generate many new plants.

I have fought a running battle with snake plants in our Florida yard since a former owner got them started. So I always considered them a big pest with no redeeming qualities. However I have now recognized that the regular Winter-time blooms of these plants are actually quite interesting from an ecological perspective (see photo). A spike of white tubular flowers emits a powerful fragrance and is actually quite beautiful, if you can get past the bad-boy image of this species. I am always interested in predicting what might pollinate specific flowers, based on flower color, shape and smell. I found out that this plant originated most likely from Western Africa but have not yet found out what pollinates it in its native habitat. However the white tubular flowers with a strong odor indicate pollination by a night-flying moth with a long tongue, possibly a sphinx/hawk moth whose larvae are often called horn worms.

I did find one article that determined that the primary sugar in the nectar of the common snake plant is sucrose, and predicted that this in conjunction with the flower structure would attract mainly sphinx moths. Note also that the authors found extra-floral sources of nectar and surmised these might satisfy creatures such as ants that might otherwise steal the flower nectar and limit the plant's ability to reproduce:
http://aob.oxfordjournals.org/cgi/content/abstract/58/4/541

So look around you with a renewed interest in plants and animals that you might have dismissed as unworthy of notice, and you may find unsuspected beauty and interest among the "bad boys" of the natural world.

Bill DunsonEnglewood,

FL & Galax, VA

The Io moth & caterpillar- some amazing natural designs

On a nature walk this morning at Stump Pass State Park in Englewood, FL, our group came across two caterpillars of the Io moth (see photo). At this stage they are a striking light green, with a red and white stripe along their sides. The younger caterpillars are brown to orange-brown. Although we were tempted to pick this beautiful green caterpillar up, I knew that this species has poisonous spines that can cause a lot of pain. One might assume that the green coloration is for camouflage, although it is so bright that it might even be considered a warning coloration along with the red/white stripes. The branched, poison-bearing spines pack a powerful jolt to any potential predator.

Strangely enough it was about three years ago that I saw the adult of this strange moth at our farm in Galax, VA. The unusually colored adult moth appeared on a window screen one morning where it must have been drawn to the lights the night before (see photos). With the wings closed the moth is cryptic in the right background and would presumably escape detection by most predatory birds. If it is detected and is poked, it opens its wings and reveals a marvelous set of false eye spots (see photo). Many moths have eye spots on their hind-wings that mimic an owl's face or just provide something scary for a bird to think about. But the Io moth has what I consider the most impressive set of eye spots. But even so I am amused that a bird would find this intimidating.
One again we can be amazed by the evolutionary process that can lead to the development of such a remarkable pattern. The variety of animal coloration is a never ending source of wonder.
Bill Dunson
Englewood, FL & Galax, VA

Sallows & Other Moths

Over the past few weeks in the evenings, whenever I turn the porch lights on, sallow moths gather.
They flutter near the screen door, and along the wall--some station themselves in little seams in the wood paneling, others perch there as if frozen into the light.

The most common is Bicolored Sallow (Sunira bicolorago). Several arrive every warm evening, little swarms of orangish yellow edged in a thin purple. As many as twenty or so zone in on the light by the front door. Two Octobers ago, I saw more than fifty, an outright crazy swirl of them that would hurdle and joust about, when I would get close. But mostly these moths just wait there, owned by the light.

A few other sallows have graced the wall:

Footpath Sallow (Metaxaglaea semitaria)
Battered Sallow (Sunira verberata)
Three-spotted Sallow (Eupsilia tristigmata)

A few other species of sallows have visited too, but I haven't keyed them out.

Other moths in the last few evenings:

Implicit Arches (Lacinipolia implicata)
Armyworm Moth (Pseudaletia unipuncta)

And likewise, several that I can't identify.

For most of October, I felt a special joy in seeing Rose Hooktip Moths (Oreta rosea). It is a favorite, a rather muted orangish rose color with a few darker lines, and of course the wings have a wonderful hook at the wingtips...at least that's the color pattern of the ones resting on the wall and screen door, up to six or seven on more than one evening.

I will have to start focusing a camera at them, or sketching some pictures and share those some time in the future. Right now, you can visit many wonderful moth web sites...I like the moth photo pages of Bob Patterson, and others at the moth photographers group web site....

http://mothphotographersgroup.msstate.edu/


I don't like to leave lights on very long, extra on electric bill, but more I think it disrupts their moth schedules. They should be foraging, flitting, courting, mating, ovipositing etc., not hunkered at my house, mesmerized and captured by porch lights. I turn the lights off soon as everyone is home from their evening travels.

What moths are you all finding these November nights?