Previously I had traveled to Sheet Harbour/Lochaber Mines, Nova Scotia, to meet my friend Derek Bridgehouse in hopes of finding columbia in his boyhood haunts.

I was surprised by the arrival of the moths at lights on P.E.I.. Charlottetown-based university personnel had no records of columbia on Prince Edward Island. Luna, polyphemus and cecropia were well documented, as were two other much smaller saturnids, Dryocampa rubicunda and Anisota virginiensis.

My experience with these moths indicates they have a very short flight season (probably a maximum of three weeks) on Prince Edward Island, usually from mid to late June, sometimes into early July when the spring has been cold.

Hyalophora columbia male in typical resting pose,
from Prince Edward Island, courtesy/copyright Darrell Gulin.

Those females I have taken at lights readily oviposit on the sides and bottom of inflated brown paper grocery bags. Often, however, they do not oviposit the first night in the bag. Eggs are fertilized at the time they are deposited, not at the time of mating, and incubation at approximately 68 F lasts 12-16 days.

I have successfully reared this species from egg to adult on Larix laricina (tamarac/juniper/larch) and on Prunus pensylvanica (pin cherry). Others who have received eggs from me have reported rearing success on Salix exigua/Salix interior (Sandbar willow) and Prunus serrotina (wild black cherry).

I have best results with small numbers of larvae (6-8/sleeve) in sleeves 67" long with a 7.5' circumference. Such sleeves are usually pulled over the tops of small pin cherry or larch trees or over the lateral branches of larger larch trees.

I find there is less likelihood of disease where there is full sun and good air circulation. I either 1) insert one-day or two-day old larvae, feeding on cut food (larch stem tips about 4 inches long) in plastic tubs, into the sleeves by laying cut stem tips over live branches, or 2) tape small strips of paper with eggs still affixed (a day or two away from emergence) onto twigs and then sleeve the foliage.

Generally the less handling and moving there is of the larvae the better the end result.

Males of this species will readily mate with female cecropia, if the cecropia females call in the early morning. Below is a hybrid female (barren) from such a cross.

Female hybrid Hyalophora columbia (m) x Hyalophora cecropia (f)
Photo by Dan MacKinnon, Montague, Prince Edward Island

I have encountered wild male and wild female hybrids of cecropia (f) x columbia (m) at my lights and at other lights in the area. The females are always large and barren and both sexes have a thin reddish-pink line just below the white pm band. This is especially noticable on the ventral surface of the hind wings.

Pure columbia lack this reddish-pm line.

Haylophora columbia female, from Montague, Prince Edward Island,
courtesy/copyright Darrell Gulin.

Columbia columbia larvae are solitary from time of emergence.

The first instar is black with some lighter colouration at the base of the black scoli. The second instar larvae retain the black colouration of the scoli, but the skin is greenish yellow. Third instar larvae become green and still have black scoli. In the fourth and fifth instars, the large red tubercles appear as three pairs near the head and the black abdominal scoli are replaced by white tubercles.

Columbia columbia larvae are very similar to cecropia and other Hyalophora species but may be distinguished by three pairs of enlarged red thoracic/abdominal tubercles in the last two instars. Cecropia have but two pairs of red-orange enlarged dorsal, thoracic scoli. Scan of fifth instar columbia larva on larch by Bill Oehlke.

Cocoons are compact and usually woven longitudinally against a branch or trunk from 6-15 feet above the ground. The cocoons have gold and silvery striations resembling the larch bark. Pupae tend to have little room within a smooth, denser inner cocoon.

I have no trouble overwintering cocoons (breeding stock) in the refrigerator crisper where pupae do not experience freezing temperatures. For the last nine years I have had 100% eclosions in June from stock put into storage in October and removed from storage in May.

Moths tend to eclose in the late afternoon. In late June of 2005, I had five males emerge on June 26 and five females and one male emerge on June 27. Three more females emerged on June 28.

Cocoons had been taken out of storage on May 25 and May 27.

I was hoping for eclosions about ten days earlier, but spring was cool and wet.

I usually take larger/heavier cocoons (hopefully females) out of storage two days before I take out the slightly smaller cocoons (hopefully males).

I save some male cocoons (from a different brood) just in case I am not successful with females calling in wild males. Thus far, however, the females have always been successful in calling in wild males.

Females, which usually emerge around 4:00 pm, are placed in hardware cloth calling cages (cylindrical cages about 14 inches high with approximately nine inch diameter) around 10:00 pm. The cages are set out on my upstairs balcony at that time, under cover of darkness to prevent predation by birds.

My alarm clock is set for 4:30 am and usually by 4:45 am the first male(s) begin to appear. Overhead flight is fast and erratic and it often takes the males five to ten minutes to hone in on the females. Male flight becomes much more controlled once they have located the cages. They can almost hover just before landing on the side of the cage.

Once the males have landed, I usually capture them in my hands and insert them into the cages (one male and one female to a cage). Columbia males are very aggressive, and pairing is almost immediate. Sometimes the female will fall to the bottom of the cage where she is joined by the male. Subsequently she climbs back up the side of the cage with the male in tow.

Inserting the males into the cages, as opposed to letting them pair through the mesh, lets me bring the cages indoors without having to worry about the separated males flying around the house.

I let the pair separate naturally (usually around 8:00-9:00pm) and then place the females, one to a bag, into inflated brown paper sandwich-lunch bags.

Occasionally I run into a female which seems reluctant to mate. I think, twice in the last three years I have had females which call, but seem to panic when the male is inserted. These females call for four or five days, attract males, but consistently refuse to pair. Most females, however, are paired within five minutes of inserting the male.

Fresh eggs are used to fill orders. I usually have eggs from several females at the same time and those, who have ordered eggs, get eggs from different females, usually separated by a wad of tissue inside the egg tubing.

During the summer of 2005 I harvested about three hundred columbia cocoons. I probably intitially sleeved six-seven hundred eggs/larvae. Larvae were sleeved at three different sites.

I do not have much larch on my own property so I get permission to use other people's trees for this species.

I put out about 120 of the earliest batch in Cardigan (about five miles from home): fifteen sleeves of eight larvae/sleeve and harvested about seventy-five cocoons. I also sleeved out some Eacles imperialis pini on pine on the same property.

Sometimes there is predation inside the sleeves, possbily by earwigs or lightning bug larvae. Sometimes there is predation by yellow jackets or stink bugs when larvae get too close to the edge of the sleeve. Even though I now cover remay sleeves with a second sleeve of deer mesh, I occasionally lose a few cocoons/mature larvae to birds which peck through the sleeves when larvae move to spin up on the branch in or near the sleeve folds where the sleeve is tied, a common practice with columbia larvae.

I have learned to do sleeving where there is good air circulation and exposure to sunlight. I have learned not to sleeve on very low branches which will tip to the ground when frass gathers in the end of the sleeve. I have learned not to overcrowd this species and to handle as infrequently as possible. Eight larvae to a sleeve usually results in only a single change. I have also learned not to force too much foliage into a sleeve. Again air circulation seems important. Larch also grows in moist areas, but areas with standing water should be avoided. Younger trees with lush "needles" often yield better results than older trees.

In 2005, a second, closer rearing site on a neighbour's property was no longer available due to a desired sale of the property. I had to find another area to rear the columbia.

The Department of Forestry has established some woodlots (Valleyfield) just a few miles from my home. Larch stands have been planted or allowed to develop naturally as soil, moisture and other conditions in the area are quite favorable.

I obtained permission from a local resident to put up a collecting light, shining toward the woodlot, on his property. I also noted that his nextdoor neighbour/son had an abundance of relatively young larch trees, probably 10-20 years old, on his property. I spoke to the son and obtained his permission to use the larch for columbia and some pine trees for Eacles imperialis pini larvae.

In some cases I had to do some thinning of alder bushes and white young white spruce trees to open up around the larch. I set out out sixty sleeves with 6-8 larvae per sleeve and had good results on this property.

I ran into yellow jackets twice and got stung on two different days. Most of the sleeves were on lateral branches, but I did cap two smaller trees and then used a heavier sleeve material and a twelve foot long sleeve over a tree about sixteen feet tall.

As larvae consumed almost all the foliage in the smaller sleeves, I moved them once, almost mature, into the larger sleeve for finishing.

I did not have time to do all the cutting required to access additional good larch branches, so I decided to sleeve out remaining eggs/hatchlings on pin cherry trees, pioneering a large cut over strip near the soccer complex. I also received permission from the land owner to sleeve cecropia, some Sphingidae and Catocala larvae on this property, just a couple of miles from home.

The columbia did not do as well as a group on the cherry, but I did get some nice full sized cocoons. I do not know if the lower success rate on the cherry was due to the foodplant or the cooler, wetter weather we experienced in late August to mid September. Highest losses to disease were experienced on both larch and cherry during the latter part of the season.

Those who received cocoons in the fall, got cocoons from multiple broods: Nova Scotia stock, P.E.I. stock reared on larch from a couple of broods; P.E.I. stock reared on cherry.

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