Bugfolks

2008-2009 Cocooning Update

By: Ian Miller

This has been my best year yet for finding silk moth cocoons.  I have been taking hikes with my lovley girl friend (Bailee) and driving around out in the country in search of promethea cocoons.  Today we came across a tree that had 6 cocoons hanging from it!!!  And then we came across another tree with 3 cocoons on it!  So far finding 6 cocoons on one tree is my record. I have only found 4 on one tree up until today.

The larger cocoons are female while the smaller ones are males

All cocoons sound and feel alive so I am pretty excited about that. Its funny because just last sunday we( Bailee and I) had found 7 cocoons and only one was alive, the rest had hatched or been diseased, so I guess we got repaid today with a find of 9 healthy sounding cocoons!  All cocoons this year have been found on White ash, Wild Black cherry, and one large cocoon on a small Elm. The majority have been spun on Black Cherry trees and im suspiscious that the one on elm had wondered from its host ( ash) because there were several smaller ash trees in the area.

I also Noticed while walking along the Chippewa River a cecropia  way up at the top of a 15 foot high Red Maple tree. So being my very monkey like self I scaled the tree ,( the tree was unharmed) and gentley peeled the cocoon away from the branch it was on and shimmyed down with one hand and jumped the remaining few feet to the ground.  Usually when i find cocoons up that high the are parasitized but to my luck this one had some weight to it and also makes a nice thud when I shake it.  So far for the 2008-2009 collecting season i have found 34 promethea cocoons, 9 cecropia cocoons, and 8 polyphemus cocoons.  Hopefully there are plenty more to come.  I will be venturing out once this warmer weather starts to melt some snow.

Please bear with me as this post may be a bit heavy on photos.  In the last entry, I described my rearing setup and the first two caterpillars which I released to pupate.  The caterpillars shown below are all over-wintering in the "bug cage" I assembled out of a wire trash can and an aluminum mesh lid cut from an old window screen:

The lid is held in place with twist ties; so far it has kept the raccoons and other critters at bay.  There is a raised platform in the bottom to keep the cocoons elevated, and the paper towels provide protection from the elements.  I keep the whole setup under a bench so it doesn't get waterlogged every time it rains (and also to make it inconspicuous to a couple of neighbor kids who kill bugs for amusement.)  I mist the cocoons with distilled water about twice a week.

I found this Polyphemus caterpillar toward the beginning of September while I was looking for slug caterpillars...  I actually thought it was a slug caterpillar at first glance, but its head wasn't drawn into the body.  The host plant is Water oak, Quercus nigra.

He/she didn't change as dramatically as the Hickory Horned Devil between molts.  Even so, the progression is quite apparent.  This photo was taken 9 days later...

And 2 weeks after that...

Within just a few days, he had spun a cocoon amongst the leaves of his food plant...

The next caterpillar I brought home to raise really was a slug caterpillar: a Smaller Parasa.  I told my husband I wouldn't keep any stinging 'pillars, but it was just too neat to resist!    This one was discovered in early October and ate American hornbeam, Carpinus caroliniana.

After 4 days...

Another week later...

He only molted once after I acquired him.  When the time came to form a cocoon, he spun it against the lid of the container.  You can see the green lid inside the "cage" in the first photo.

In mid-October, I came across some Giant Swallowtail caterpillars on Common Hoptree, Ptelea trifoliata.  Since I've never seen the adult butterfly, I decided to add one to my growing menagerie.

It only took 2 days to start pupating...

I started to worry that something had gone wrong when it stayed like this for another 48 hours; however, on the third day, it became a proper chrysalis...

I found the final caterpillar in late October: a Frosted Dagger moth.  As far as I can tell, these guys only eat Hazel Alder, Alnus serrulata, and there are no photos of the adult anywhere on the internet.  The larva looks like this...

I had read in David L. Wagner's book Caterpillars of Eastern North America that most dagger moths require "soft (dead) wood in which to tunnel," and that "some make a hardened cocoon by adding bits of chewed wood to the wall of the cocoon as it is being spun."  That is exactly what this one did...

Hopefully they will all emerge successfully when they're ready, and I'll be able to add images of the adults!

Carmen Champagne

I've been a major bug enthusiast for a while, but this year was my first attempt at rearing. It started with a Hickory Horned Devil... I'd been practically obsessed with finding one ever since I first heard about them, and in mid-August I discovered two on a persimmon tree. I was thrilled, but these caterpillars were newly hatched/first instar. What I had always envisioned was a hot-dog-sized behemoth of a caterpillar, so I decided to take one home and raise it.

The setup I put together was fairly simple: an old plastic fish bowl with some sheer fabric over the top secured by a rubber band. Later on, I acquired (and in some cases improvised) other rearing containers including the ones in the photos below. I would line the bottom of the container with some moist paper towels. Besides providing food, maintenance consisted of removing frass and lightly misting the 'pillars with distilled water every couple of days.

In order to keep the foodplant clippings fresh, I bought some little plastic bottles for fifty cents at a craft store and filled them with water. After removing the screw-on caps, I carefully sealed off the tops with duct tape. This works well; however, the caterpillar can get stuck if the corners of the tape start to lift... I always add an extra strip around the rim to keep that from happening. The clippings are inserted through a hole poked in the duct tape.

Watching the Hickory Horned Devil grow and change was an amazing experience.  To give you some idea of the progression, here is how he (or she) looked when I found him...

5 days later...

Another 5 days...

9 more days (just before a molt)...

A week later...

On the 36th day, he was finally ready to pupate...

By this time, I was also keeping an Imperial moth caterpillar.  This one was eating boxelder; I've never been able to persuade any of these guys to switch host plants.  This photo is from the beginning of September, his/her first molt...

8 days later...

And shortly before pupation, 17 days after that...

Since both Imperial moths and HHD pupae pass the winter underground, I eventually decided that releasing them would be the best thing to do.  As much as I wanted to see their adult forms, I knew I would feel awful if I bungled their care.  When it was time (caterpillar wandering off the foodplant/ emptying its digestive tract,) I took each of them out into the woods and waited for them to start burrowing.  Neither took long to choose a spot, but the digging was a very slow process.

I did end up keeping cocoons from a few other species I was more comfortable trying to over-winter.  I'll try to post photos of them soon, but I think I've taken up enough space for one day. 

Carmen Champagne

Finding Wild Silk Moth Cocoons

Ian Miller

Every fall/ winter im very active with hunting and fishing.  I usually end up getting bored and searching for cocoons while im walking through the woods or along lake/river banks.  I have found wild cocoons or larva from every species of wisconsin saturniidae but the columbia silk moth( likley because i dont look on larch which is there primary source of food)  So far this year i have found 3 wild promethea cocoons, 2 wild cecropia cocoons, 3 wild polyphemus cocoons, one wild io larva that cocooned, and i recieve some overwintering wild luna cocoons from down south.  Typically when im searching for cocoons i start by looking on the shrubs that i rear the larva on ( birch, cherry, willow are the three main plants i always look over). 

Cecropias tend to cocoon near the base of the trees where they will be covered with snow to insulate them over the course of the winter but some individuals will spin up at eye level length wise on braches. Since cecropias have such a tendancy to wander away from there host plant its hard to judge what they are eating by what plant you find them on.  Here they show a preference for cherries but i have found them on ( Red Maple, White Ash, Choke Cherry, Speckled Alder, Box Elder, river Birch, paper birch, Liliac, Dog wood, Elm, and honesuckle)  Cecropias are a highly suseptible species to disease and parasitization.  Last year i found over 30 cocoons that were all containing dead larva my suspision lead me to believe that it was NPHv.

Left: Sleeve reared cecropia Right: Wild Cecropia

Polyphemus cocoons can either A. be securley fastened to a branch or B.  spun up around the leafs near the base of their host plant.  I usually find polyphemus on birch and willow and occasionally in dogwoods and wild black cherry.  I start by examining the braches to see if any were generous enough to spin where they are easy to find then i will sift through the leafs and grass at the bases of the trees themselves.  Polyphemus are the most common wild silk moth in eau claire county i have reported over 100 seperate males in one night at scenting females.

Some collected male polyphemus! All were released after photo.

Promethea moths are a highly parasitized species. Finding their cocoons is very easy i always start by searching wild black cherries that are scattered throughout feilds and open areas.  Moths usually preffer open areas with trees of shrubs that are spread out.  Promethea cocoons hang like ornaments from host trees and are one of the easiest to find.  I have found them on dog wood, hazelnut, and maple but almost always are found on cherries.  ( i have reared the species on maple before but they do not get nearly as large as they do on cherry)

Promethea larva on cherry.

Luna moths are among one of the most difficult cocoons to find along with the io moth.  They both rarley ever fasten their cocoons to a branch and always spin up in leaf matter at the base of host plants.  I dont ever target looking for their cocoons but i have come across them on a few occasions looking for polyphemus moth cocoons.  Lunas show a preference towards paperbirch and black walnut here in eau claire and ios will almost eat anything.  Ios tend to crawl several feet away from their original host plant before they spin up in dead leafs.

Male Luna

For anyone who has larch on their property it may be wirth searching for columbia silk moths.  Their cocoons are very well camoflauged to look exactly like the bark.  I myself have never found a wild columbia larva or cocoon but we dont really have much for larch and tammarack around here. They are reproted futher north than eau claire and are probably much less numerous than any of the other moths.

(Io, Luna, Polyphemus, Promethea, Cecropia)

Note: Its amazing how much darker wild cecropia cocoons are from sleeve reared ones. Also the size of wild cocoons can't compare to cage or sleeve reared speciemens.

Mike and I found a beautiful big caterpillar crawling across the driveway a few days ago.  It's a Giant Leopard Moth caterpillar (Ecpantheria scribonia).

It's very striking - about 2 1/2 inches long, with shiny black bristles and bright red bands and spiracles.

It rolls up into a tight circle when I disturb it.

It will spend the winter as an almost grown caterpillar, and make its cocoon in the spring.  I kept it in a cage for a few days and it happily ate lilac leaves.  But I decided I didn't want to risk trying to keep over the winter, so I released it.

One of my slug caterpillars made a cocoon.  It's either the Jeweled Tailed Slug caterpillar, or the Yellow Shouldered Slug caterpillar.  When I looked through the leaves where they were hanging out, they had both disappeared, and I found one cocoon.  It's quite small - about 1/2 an inch long.  Hopefully I'll be able to watch it next spring and see what comes out.

My Giant Swallowtail caterpillars are continuing to grow.  It's a race to see if they can finish their caterpillar stages before the leaves of the prickly ash drop off.

This is one of the bigger ones - it's about 2 inches long.

I've got them in separate cages now - ice cream buckets with lids cut open and lined with plastic screening.

I thought I would show you what my caterpillar raising set up looks like.  This is on our screened porch, so they're exposed to outside temperatures.

The small cages on the shelves are for smaller caterpillars, the large ones on the floor are mostly Giant Silk Moths - Lunas, Polyphemus and Cecropias. I'd love to see other people's set ups.  I'm outgrowing my space, and I'd like to get some other ideas.

Marcie