I frequently get asked, "What is the easiest Saturniidae species for beginners to rear?"

My response has always been Actias luna. I do most of my rearing outdoors in rearing sleeves, pulled like socks over tops of trees or over lateral branches. Most species do best when reared in such fashion.

I have also had very good results rearing lunas indoors on cut food in large plastic tubs or glass jars, and I have provided instructions for many people to have similar results. Indoor rearing allows for easy observation of these beautiful creatures, and rearers, young and old, can have success.

I work with a number of subcontractors in the United States who can ship luna eggs for me at various times, starting as early as March in Alabama and as late as September from New Jersey. In most cases, the subcontractors have either captured wild female moths at lights or have obtained pairings of their own reared or purchased females with wild males. Fresh eggs are shipped at a time appropriate to their rearing in the respective areas of customers. Shippers indicate the date of deposit with each shipment. Eggs typically take eight days (80-85 F) to twelve days (68 F) to incubate, depending on storage temperature.

Upon receipt of eggs, please carefully place them (gently pour them) in(to) a plastic tub. Put the lid on tight, no airholes and record the date of deposition. Here in Canada I use Ziploc, clear plastic tubs, about sandwich size. Gladware, Tupperware, etc. will also work fine. Clear plastic will let you see the emergent larvae.

Place the tub where it will get ambient light but will not be exposed to direct sunlight. It is very, very important that foliage not be placed in the container with unhatched eggs.

Putting foliage in with unhatched eggs can be disastrous for several reasons:

1) the leaves give off carbon dioxide which can literally suffocate the tiny larvae inside the unhatched eggs in the closed container,
2) the leaves also give off moisture which can condense on the floor of the container and "drown" the eggs, or
3) moisture can condense on the egg shell and cover the micropyle also suffocating the larvae.

In response to my coments written above in red, I recently received this request and query: "Could you please confirm if I have understood this information correctly: as I understand your comment, I believe it suggests that leaves through the process of photosynthesis release carbon dioxide.

"I was always under the impression that photosynthesis gives off oxygen via the uptake of carbon dioxide? I have never heard of leaves producing carbon dioxide.

"Is this a mistake in the wording of the article?"

I indicated that during the process of photosynthesis, the chlorophyll in green leaves combines water, taken up from roots and through stems, with carbon dioxide, taken from the air, to produce sugars and starches and releases oxygen. I also explained that leaves and all living things need oxygen, and it is during the respiration (breathing) process that plants take in oxygen from the air and give off carbon dioxide. In daylight hours the plants take in much more carbon dioxide for photosynthesis than they release through respiration, but at night plants give off carbon dioxide during respiration and are not absorbing carbon dioxide from the air.

I also indicated that respiration and photosynthesis are both processes of living things. I do not know when a leaf that has been cut off from its water supply is considered dead, but I know that in a closed container such leaves will certainly give off moisture, and will begin to wilt. Deterioration is usually quite evident after three or four days in a closed container. I expect the decay process starts shortly after the leaves have been detached from their water supply. Without water, needed during photosynthesis, the intake of carbon dioxide would stop and output of carbon dioxide would increase, either through continued respiration or through decay, both of which utilize oxygen and give off carbon dioxide.

I am not a chemist, and I have never analyzed the content of the air inside such a closed container, but it is obvious from condensation seen on insides of such a container, that the relative humidity has certainly increased, probably to 100%, and I suspect oxygen levels are lower and carbon dioxide levels are higher than would be experienced in a vented container. The problem with using a vented container for very young larvae, is they will not obtain enough moisture from the foliage, detached from its water supply.

I do know for sure, that for whatever reason, it is not a good idea to put detached foliage in a closed container with unhatched Saturniidae eggs.

Egg fertility: If you have had a female moth hatch out of a cocoon, she will not lay fertile eggs unless she has paired with a male moth. Most females remain still for two to three nights. They are conserving energy, but are actively seeking a mate by extending a scent gland from the tip of the abdomen at night. This "wick" exudes a pheromone (perfume) into the night sky. Male moths fly into the wind in a zig-zag fashion, until their sensitive antennae pick up the scent. They are then able to track the scent plume, find the female moth, sometimes after flying several miles, and mate with her. In most cases the pair remains coupled for approximately twenty hours, or until dusk. Sometimes, however, the pair will separate after only a couple of hours.

Wild female moths captured at lights have usually paired before they fly. However, in the case of both reared moths and captured moths, females will usually (not always) stop "calling" and will start laying infertile eggs if they have not successfully paired by the end of the third evening.

The eggs do not become fertile at the time of copulation. The eggs get fertilized as they pass through a mix of male sperm, seminal fluids and "glue", stored in the female's body. This immersion/fertilization takes place as the female expels/deposits the eggs. Thus eggs deposited four days before other eggs will usually hatch four days earlier, even though they have come from the same female.

Neither male nor female Saturniidae have feeding tubes or mouth parts. They do not eat as adult moths. Instead they live, usually only for about seven to ten days, by utilizing fats stored in their bodies from their caterpillar days.

Most rearers, myself included, gather eggs from the insides of brown paper sandwich or grocery bags. Once the female has separated from the male, she will begin depositing eggs from dusk onwards. I place a paired but separated female in an inflated brown paper sandwich bag and fold down the top half inch of the bag twice to secure the moth inside the bag. I then place the bag in a dark, quiet space in the house. Usually there will be much activity in the bag, starting around 10:00 pm as the female deposits eggs, often as many as 150 of them the first night, on the inside of the bag.

The next morning, I will remove the female to a new paper bag, put a new date on the fresh bag and return it to its storage location. The female will usually remain quiet until evening when she will resume egg laying. Probably only half as many eggs will be deposited the second night, and this diminished egg laying continues until the female has deposited all eggs or runs out of stored fats and dies.

Most females will lay approx 250 eggs, but some large females have been known to lay over 400 eggs.

These fresh eggs are tough and can easily be removed by fingers and finger nails from the paper bag surface. Orders are packed up and shipped the same day.

Eggs are often shipped in aquarium tubing or other small containments. They should be gently and carefully removed from containment and placed in the storage tub(s) described above. Noting and recording the date of deposition should give you an approximate idea of when the eggs can be expected to hatch (8-12 days from date of deposit, depending on temperature, maybe longer if your house is cool). In most cases the caterpillars will all hatch on the same date, usually in the morning, within an hour or two of each other.

The hatchlings literally have eaten their way out of their egg shells. Their little digestive systems are full of egg shell, and sometimes they will not begin to feed for several hours. If you have anticipated the hatch date and have placed some foliage in the closed tub(s) with the eggs, you probably will have DISASTROUS results. Please do not place foliage in with unhatched eggs.

Initial Feeding: Hopefully, before you order eggs, you will check to see that you have one of the prefered host plants available. If a prefered host is not available, then one of the alternates will usually (not always) be accepted. Gather one or two leaves from at least one host plant. You can gather a couple of leaves from a couple of different hosts to see which the larvae prefer.

The leaves should not be covered with rain or dew and should not be cold (gathered on an early spring morning) when they are placed in one of the feeding tubs. If they are wet, pat them off thoroughly with dry paper towels. If they are cold, allow them to sit at room temperature for ten to fifteen minutes and then pat off any condensation that may have formed. Hopefully you have not gathered leaves from any trees that have recently been sprayed. It is also not a good idea to have any insect repellant on your hands/fingers while you are gathering the foliage.

I suggest you work with two tubs at this time. Once hatching has begun, I recommend you pour off any unhatched eggs and any empty egg shells to a second egg storage container. Then you can place your leaves, probably no more than three or four, in with the larvae, so that portions of the stems or leaves are in contact with bottom or sides of the container. The caterpillars will usually find the food quite successfully on their own. If you ordered and received twelve eggs and you can see twelve tiny larvae in the tub, then you know all the eggs have hatched, and the empty egg shells can be discarded. If there are fewer larvae than there are eggs, then you can expect more to hatch later that same day or the following morning. Again, please do not put foliage in with unhatched eggs. THIRD REMINDER

Hatchling luna larvae (caterpillars) show two different color forms. They can either be all greyish green or they can be greyish green with black markings: a thin black strip across top of the head, a black lateral stripe, one on each side, and a thin black bridge across the back near the first abdominal segment.

Studies have been done by others to see if these different markings are indicative of gender or any future differences in larvae or adults. The reports indicate that the variance in markings/colour is not indicative of any real differences in gender or adult patterning/colouration.

Rearing Container

Now that the larvae have hatched and food has been presented to them, they should begin eating within twelve hours. Little frass pellets (poop), tinier than pepper granules, should be visible on the bottom of the plastic tub. The plastic tub or jar that you are utilizing should have a tight fitting lid. There should not be any airholes, no porous screen, no cloth cover. NO AIR HOLES.

These larvae are tiny and have a very large surface area to mass ratio. They will not be getting as much moisture from the leaves that you have collected and placed inside the container as they would be getting if they were feasting on leaves still affixed to a live tree. Also, indoor air tends to have a lower relative humidity than outdoor air.

If you figure that the tiny caterpillars probably need some air and use a porous screen or cloth top or poke holes in the jar lid, then you are inviting DISASTER. The tiny caterpillars do not need much air. There will be plenty in the closed container(s). Trust me! They do need adequate moisture and a closed/sealed container will help prevent too much evaporation from foliage.

Changing Food

Even if you have followed instructions carefully and the food/foliage inside the container still looks fresh, it should be replaced at least every other day. The moisture content is that important!

1) Go get some fresh foliage.
2) Make sure foliage is dry and at ambient indoor temperature.
3) Place a dry paper towel or sheet of newspaper on your changing table (bassinet, chuckle).
4) Open the tub with the feeding larvae and gently remove the larvae on the foliage to the towel or newspaper on the table.
5) If there are any larvae on sides of container, not on foliage, either leave them there or coax them to crawl onto a tip of fresh foliage.
6) Wipe out any frass and condensation from the inside of the tub, being careful not to disturb any larvae that might be clinging to the side or bottom.
7) Put room-temperature, dry leaves into the cleaned container.
8) Examine both sides of older foliage. Use a pair of scissors to cut strips of old foliage so tiny strips (with larvae attached) will lightly fall onto fresh foliage. Make sure you get them all.
9) Put lid back on tight.

The caterpillars will soon crawl, on their own, to the fresh foliage and will begin feeding. Usually this procession from old food to fresh leaves takes place within twenty-four hours. It is a good idea to remove the old, vacated food strips from the container. They can get moldy or support bacterial buildup, and their continued deterioration will release too much moisture in the closed container.

At least every two to three days repeat the nine steps of the "Changing Food" procedure.

Here on Prince Edward Island where I rear most of my luna larvae outdoors on live trees covered with rearing sleeves, the larvae require approximately five or six weeks (35-42 days) to grow from hatchlings to cocoon spinners. It is rare that we get temperatures above 90 F in summer time. Some years it seems it is even rare if we get temperatures into the 80's. Most summer days are in the 70's and we usually get cooler, darker, rainy days once or twice a week. Night time temps often dip into the 60's.

If you rear these same larvae outdoors in a warmer, sunnier climate, development will be much more rapid. If you rear then indoors were temperatures are more even and do not drop below 70, development will be more rapid than outdoor rearing on P.E.I..

I have reliable reports of these insects spending as few as 19 days in the larval stage when reared at warm temps, with either high humidity or lots of sunshine (California, Louisiana, Florida).

Although the caterpillar skins are somewhat elastic, they are not stretchy enough to provide for the relatively enormous change in size that accompanies each caterpillar's development. After three to seven days of feeding, the larvae will become still, often anchoring themselves with a bit of silk. They are going through a molting process where the head capsule will be discarded, and muscular contractions of the caterpillar's thorax and abdomen will result in "sloughing" off the old skin. The contractions occur in such a fashion that the old skin is forced, often in a single, contracted piece, toward the posterior end of the caterpillar.

Often the caterpillar will turn around and eat the discarded skin. Sometimes it will just crawl away and begin feeding on fresh foliage.

Almost every year I will get a report from someone who has found an Arctiidae caterpillar (usually quite furry), where the finder indicates he/she has witnessed a miracle of spontaneous generation. "Where there had been a single one-and-a-half inch caterpillar on a single leaf in a small jar, there are now two caterpillars, one just a bit smaller than the other." I reply that the single caterpillar has shed its skin.

Luna caterpillars are said to be in their first instar stage when they hatch from the eggs. Each time they shed their skins, they move into a new instar, i.e., second instar, third instar, fourth instar and the fifth instar. The time spent in each instar will vary with local conditions, usually anywhere from 3-7 days in each of the first four instars, and 6-14 days in the fifth (final instar).

Larvae are very tender 1) each time they are preparing to shed their skins, 2) during the shedding/molting process and 3) for an hour or so after the old skin has been discarded. They should not be removed from their moorings during the molting process. If you have to move them for a food change, leave them affixed to leaf or stem and gently place them on top of fresh food offerings so the actual caterpillar is not in direct contact with any new food. You don't want the old skin to get hung up in any way as it progresses in its rearward journey.

Quart or liter-sized jars make good viewing containers for the larvae when they are small. If you have started with a dozen eggs, three such jars would provide ample room for four caterpillars each during the first three instars.

I recommend something larger for the fourth and fifth instars. Fifth instar larvae can exceed three inches and be as thick as an average finger. Gallon glass jars, still with lids on tight and no airholes, make nice indoor rearing containers for fourth or fifth instar larvae, now only three or four to each jar, fewer if you have access to lots of jars.

Just before the caterpillars are ready to begin spinning their cocoons, they will clear their guts with a loose, runny, messy stool. I wouldn't want to crawl around in someone else's poop. Health wise it is a good idea that the caterpillars not come in contact with such leavings. You don't want to overcrowd the larvae whether outdoors in a sleeve or indoors in a jar.

Observation of the spinning process can be interesting. The caterpillars work tirelessly to pull some leaves together, anchoring them with a continuous strand of silk. The cocoon is often complete within a few hours. Generally (not always) luna caterpillars that are going to overwinter in their cocoons will take on an amber to burgundy colouration just prior to spinning. They tend to spin a darker, coarser, thicker silk cocoon than the larvae (successive brood) which are not going to overwinter.

Actias luna "amber" fifth instar, Waynesboro, Pennsylvania,
August 7, 2009, courtesy of Kristina Kollman.

Successive brood larvae tend to spin lighter beige cocoons with finer silk as compared to the overwintering brood. In either case, caterpillars will shed their skins one more time inside the cocoon, usually 2-5 days after spinning, depending upon temperature, and enter the pupal stage. If you hold a five day old cocoon up to a light, you can usually see the outline of the pupa and the discarded skin through the walls of the cocoon. Luna pupae tend to be quite active.

I once sent a first time customer five luna cocoons. Upon receipt she "freaked out" and in a bit of a rage phoned me to complain that my cocoons were full of wasps and bees. She could hear them buzzing around in the cocoons. I explained that the sound was the sound of the pupae wiggling against the sides of their cocoons. I am not sure that she believed me until the beautiful moths emerged in the spring.

I usually place my fall harvested cocoons in a large open box on a shelf or even on the large hearth under and beside the inactive wood burning stove. Each box of a couple of hundred cocoons sits there quietly until I reach in to pick out some cocoons to fill an order. The slightest disturbance will often set the entire box of cocoons into a frenzied racket. Complete quiet usually follows within ten to fifteen seconds of the disturbance.

Cocoon Care: My late summer, fall (August, September) harvested cocoons sit in the boxes described above, at room temperature, usually until late October, sometimes even into late November. By this time I have usually sold and shipped most of them. I have already picked out about twenty of the very biggest cocoons to retain for breeding stock. These are placed in a sandwich sized ziploc plastic container (lid on tight, no air holes) in the crisper compartment in the refrigerator. They remain there from October-November until May. I do not mist the cocoons.

There is a page I have already put together about how to handle/overwinter the cocoons at Overwintering pupae, and there is another page for setting up the emergence (eclosion) cage at Emergence Set-up.

Many of you will have cocoons that are not going to overwinter. In the spring of March 2008 a shipping partner in southern Alabama obtained a luna pairing (wild males flying) on March 9. He reared the larvae outdoors in sleeves and the caterpillars started spinning cocoons on April 27. I suspect moths from these cocoons will begin hatching the second or third week in May after spending only two to three weeks in cocoons. In contrast, on March 9 on P.E.I. in eastern Canada, where I live, we were having a blizzard. There are still no leaves on the trees and there are patches of snow on the ground in shaded ditches as of May 3.

In Alabama, the moths that emerge in early to middle May will go through another cycle that will likely result in another flight in late June to early July. As the temperatures get even warmer in the deep south, larvae and pupae develop more and more rapidly. The late June flight will probably result in adult moths flying again before the end of August, and that flight will probably result in another flight in October. Most of the cocoons from larvae from that flight will overwinter, but there will be some that hatch during warm spells in December, January and February, especially if they are resting on the ground in a sheltered spot in a natural heat trap.

What can you expect? The best science seems to indicate that larvae take their cues from the photo period (hours of light) that they experience during the time that they are in fourth instar. If larvae are still experiencing as many as sixteen hours of daylight when they are in their fourth instar, they will likely not produce the diapausing/hibernating enzyme that will allow them to remain dormant through the "leafless" winter months that we experience in the northern states and Canada. If they are experiencing only twelve hours of light while in fourth instar, they will prepare to diapause.

There is considerable range between twelve and sixteen hours of daily light, and larvae experiencing those intervals will be mixed in diapausing and non-diapausing cocoons/pupae with higher percentages in one condition or the other based on proximity to the determining photo periods.

If you take eggs deposited in June from a single-brooded region of northern U.S. or Canada and rear them in the southern states, they will produce another brood. If you rear those same eggs indoors in the north where they would normally single brood, and you have the rearing jars sitting on a desk top or living room shelf where house lights are on until 11:00 pm, the extra light will "trick" the caterpillars into "thinking" (biochemical response) there is enough light and warmth to keep leaves on the trees for another brood, and they will likely emerge in as few as twelve days after spinning cocoons.

If you take eggs from a June flight in the deep south where there would normally be at least another two broods, and you rear those eggs in a single-brooded region, under close to natural conditions, the fourth instar larvae will register that hours of daylight are diminishing to the point that there would not be time for another brood. Larvae will then develop the enzyme which causes them to turn the amber to burgundy colour, and they will produce a thicker, darker silk that will allow them to withstand the rigors of a northern winter.

I do not know how much cold (minimum temperature and number of days) non-diapausing cocoons can withstand and still be viable. It is generally thought that non-diapausing cocoons cannot withstand a prolonged deep freeze. Experiments in Alabama with overwintered stock (2007-2008), should shed some light on that question.

My best suggestion is that if you wish to rear larvae and have luna cocoons that overwinter, then you need to rear in such a way (at such a time) that larvae pass through their fourth instar with hours of light under 14 hours per day and be on a diminishing photo period cycle. If you ask me questions accompanied with specific information supplied, I can only offer a best guess. Other obervations would be appreciated. Please provide data: date, location, rearing conditions if you are going to submit observations. Please provide same if you are going to ask questions. Email: Bill Oehlke.

General notes and cautions/suggestions:

There are may ways to rear luna moths. Airtight jars/containers is recommended for indoor rearing, at least for the first three instars to prevent desiccation/dehydration of larvae. Once the larval bulk increases, the airtight conditions to conserve the moisture in the foliage is probably not quite as critical, but I would recommend putting the cut ends of foodplant stems in water that the caterpillars cannot crawl into if you are going to rear outdoors on cut food in screened cages or if you are going to rear indoors (after third instar only) on cut food in an airy container (screened cage).

You can also wrap the cut ends of foodplant stems in a very wet paper towel (around the sides of the stem and across the bottom of the stem) and then wrap the stem-end and paper towel in an home made aluminum-foil cup. Take a six inch long strip of aluminum foil, probably twelve inches wide. Fold it so you have a double sheet that now measures six inches by six inches (four by four inches would probably do). Fold this upward around the paper towel so that the paper towel and stem are in the center of the fold and bring up the foil to tightly wrap around the stem and paper towel. Secure so moisture won't leak out, so moisture is reduced in its ability to evaporate into a closed container and so that caterpillars can't get into the wet/water.

Many people have had success using fresh cut food with no water outdoors as long as food is kept very fresh and does not wilt in direct sunlight.

Many people have had great success using cut food with stem ends in a bottle or jar of water outdoors. Just make sure caterpillars can't get into the water. They will crawl in and drown.

Few, if any, people have success rearing young, tiny larvae indoors in airy containers without providing the extra moisture. The larvae desiccate. The desiccation is perhaps not so severe a hazard for larger, more mature found-larvae.

Larvae tend to have prefered hosts. Some species have larvae that seem very limited in what they will accept as foodplants. Lunas, fortunately will generally accept a variety of hosts. White paper birch is a good choice in northern locations. I have also utilized beech and staghorn sumac on Prince Edward Island.

Sweetgum and other gum trees (eucalyptus in California, black gum, blue gum) and most of the nut trees (hickory, walnut, butternut) are usually great hosts. Pecan often works well in the southern states.

Most willow species are accepted and often (not always) oak species are accepted. There are additional foodplants mentioned on my public website and also on the WLSS but I think they would be less commonly accepted.

If you are in an area where you do not have one of the prefered hosts, offering the hatchling larvae two or three different types of leaves might help you determine, which they prefer. Sometimes you can stimulate feeding by tearing a bit of leaf so leaf juice odors can "rouse" the larvae.

Avoid direct sun in any containment that can overheat. If you are using a sealed container and you notice condensation forming on the sides, you have too much humidity. Wipe condensation off as soon as you see it with a dry cleanex or paper towel. Too much foliage at one time might be the culprit. If jar glass gets cool at night and sunlight warms foliage and air inside container in early morning, causing rapid evaporation, the moisture in the air will condense on the glass. Wandering larvae will crawl into the moisture and drown. It doesn't take much moisture to drown a tiny caterpillar. If you catch a "drowned" caterpillar soon enough and place its seemingly lifeless, limp body on a dry paper towel, it will sometimes revive.

If this is a first time rearing experience, check first to see if you have available foodplant that you can pick and/or sleeve. If sleeving is a possibility, make your own or purchase one. Buy a dozen eggs as starters, rear nine indoors to watch and three in the sleeves where you will likely have a better result.

Visit Supplies for sleeve prices.

I suggested you pour off unhatched eggs and only place foodplant in with larvae that have already hatched so they can crawl to the food. I often use a thin metal spoon or plastic spoon and very gently slide it under the feet of the tiny larvae from the side or head area or let them crawl aboard. Some people recommend a soft small paint brush, the kind a child would use to paint by numbers. You need a steady hand and some patience and practice. You might squish a few caterpillars initially, but, if you are careful, you can usually lift them with the spoon and can gently brush them off the spoon onto the foliage without harm with your finger tip.

Adut moths that emerge in the spring from overwintered cocoons have reddish-burgundy outer wing margins. There are also thin red stripes on the bodies of the males. This red-burgundy colouration and the body stripes are only present on the spring broods.

Good luck. I have reared thousands of luna caterpillars over the years, and there is still something very magical in the appearance of a mature larva, especially if it has turned a bright burgundy just before spinning. Large translucent green larvae are also a wonderment.

Sometimes people who have ordered cocoons in the fall, will send in another order in the very early spring. They are worried that the cocoons they have overwintered, either set outside in a cage through snowstorms and bitterly cold temperatures or set in a tub for many months in the refrigerator crisper will not emerge. It is amazing to us all how this cycle of nature repeats itself year after year. Almost every year I have 100% eclosions from the cocoons that have set in my refrigerator from November til May.

If you are going to overwinter the cocoons outdoors, make sure they are in a rodent proof cage, and one that will not overheat. It is also recommended that the cage sit on the ground and there not be airflow under the cocoons. Windchills could take a toll. In their natural environment luna pupae spend their winters in cocoons that have fallen from the trees during leaf drop, or the larvae have crawled or dropped from the tree and spin cocoons among leaf litter.

The adult moths are beautiful!

Actias luna male, on hydrangaea foliage, reared on Carya glabra,
courtesy of Alex Baranowski.

Use your browser "Back" button to return to the previous page if you are accessing this article from a link on another webpage, such as the Bill's Articles section of the WLSS. Best of luck!