Most folks are concerned with killing bugs, not nurturing them. Why do we spend so much time and effort growing these little caterpillars into moths? Several reasons... first and most obvious, is to get perfect specimens for our collections. It is rare indeed to collect a perfect specimen in the wild, one without rubs, tears or missing wing-parts. These moths seem to be more fragile than most butterflies, which are commonly collected in very good condition. It is even more difficult to collect a perfect matched pair of male and female. If you successfully rear your own, you are almost guaranteed to have a nice matched pair for your collection. The second obvious reason is so that we can explore the natural history and lives of these creatures. While it's great fun and always an adventure to go out lighting for moths, if the adults of a species are the only ones ever encountered the collector is missing out on some very striking and wonderful creatures. For example, Sphingicampa hubbardi is a relatively unremarkable moth in it's adult stage. It is pretty enough with red hindwings, but the last instar larvae of this species is something that makes everyone who sees it say "WOW that's cool!" Of course we'll never duplicate the exact "natural history" of anything that should be living on a tree in the woods when we have it in a plastic bucket in our kitchen, but you get the point. Watching a tiny egg hatch into a tiny caterpillar, then grow into a sometimes very large and impressive caterpillar, spin a cocoon and pupate, then finally eclose into a large beautiful moth is very interesting. When we can share this with our family or others who have not been exposed to it, the whole crazy hobby gets a bit more satisfying. Third, and not as important, is the fact that there are many collectors scattered around the country that don't or won't have access to some species you may find common. The internet has enabled collectors to network and contact each other with an ease that was unavailable until recently. Fourth is the fact that collectors (like me, for example...) often do not have the opportunity to spend nearly as much time in the field as we would like. Depending on home base location, family and work obligations, finances, and other stuff, a collector may only be able to go out collecting "seriously" a few nights per year. When a female of a desirable Saturniid species is captured, almost always it will produce fertile ova. Obtaining these to rear through a generation greatly extends the season and our involvement with the bugs. Hey, we can't all drop everything and run off to Mexico for a few nights of collecting everytime we feel the urge! Ha ha!
Keep in mind that it is usually illegal to trade live insects, in any stage of life, across state lines in the US. There are actually "Bug Cops" that work for the USDA. I met one in Arizona. For real. They are mostly concerned with any species that may create an agricultural impact. The only US Saturniids that have ever come close to this are some species of western Hemileuca. BUT they won't care, and you could be breaking the law if you trade or carry live insects across state lines. Kinda stupid, I know, that you could get busted for rearing a handful of big harmless moths, but that's the way it is.
OVA
LARVAE
Because of my home area (desert southwest) I keep the new larvae in the same small plastic containers for the first week to two weeks. Supply the larvae with some clean leaves of a plant they are known to feed on in the wild. You may need to get creative... If any know plants do not occur in your area, try for some closely related plant species. It's good to offer the larvae a few different species if possible. They will select the one they like the best. I've found this true with Automeris iris... they didn't accept Red Oak the first or second day. I offered them a combination of Desert Willow and some kind of Locust the third day, and they all moved over to the locust and began chowing away. The tiny new larvae do not eat much, and it is hard to tell if they're actually eating by looking at the leaves. The best way to tell that they are taking the foodplant is to look for frass (caterpillar poop) on the bottom of the container. From new first instar larvae, it looks like dust on the bottom of the container. You'll know it when you see it.
PUPAE
ADULT MOTHS
NO GUARANTEES
Conceived, created, edited, and published by Hunter and Joel. Kelly is the Creative Consultant.
The ova of most insects including the ones we are concerned with are remarkably durable. They do not need any special care other than keep them from getting cooked. Don't leave them in direct sunlight or in your car in New Mexico in July. Keep them less than 100* F and they should be fine. 80* to 85* is about perfect for most species. I usually keep ova in small, 4 ounce capacity "reusable" plastic containers from the grocery store. Most ova will be either "loose" in the container or glued to a piece of paper by the female that deposited them. Most fertile Saturniid ova will hatch within 14 days of being deposited. There are some exceptions. Sphingicampa ova are known to develop and hatch within as little as five days. I know this is true for S. hubbardi. Some ova that have been produced by fourth and fifth generation captive inbred females may take a very long time, 3 to 4 weeks, to hatch. They may also show decreased vitality... High mortality and small weak size. Sometimes not, too. A warmer temperature may speed up hatching by a day or two. I wouldn't recommend refrigerating any ova unless they are of a species that overwinters in that stage. I have found it POSSIBLY beneficial to put a small piece of paper with one drop of water soaked into it, in the container if the ova have been overheated and possibly dehydrated. I have done this with some Actias and Antheraea ova with success. Care must be taken to not swamp the ova... just a drop of water is enough to raise the humidity in a small container. Don't freeze them, crush them or cook them and they'll be OK. You will encounter ova that are infertile or just don't hatch. Usually all fertile ova in a batch will eclose within 3 days of each other, usually all within a few hours. Those that are infertile will usually collapse. Some will just plain not hatch. Most ova that are going to hatch undergo a noticeable change in appearance shortly before the event... Automeris ova get slightly darker or gray the day before hatching. Citheronia and Eacles ova shells ("chorion") turn transparent. Antheraea, Actias, and Hyalophora just pop open one day.
It's always a big day when larvae decide to hatch. Now the work begins! It's not vital to have foodplant on hand when they hatch, just be able to get it that day. Some species (Antheraea species for sure, and Automeris) will make a first meal of their eggshells, and that will hold them over without starving for a day or so. Many species simply will not eat for a day after hatching. I've found this to be pretty normal, so don't panic when it seems as if the new larvae won't eat.
The "tupperware" arrangement is good for the first week or so after hatching, because it keeps leaves from drying out too fast. At least a couple of times per day, the containers must be opened to allow fresh air in. The humidity will be very high inside the containers and enough fresh air must be circulated to eliminate condensation in the container. Frass must also be cleaned out. The foodplant should be replaced at least every 48 hours, preferably every day. The caterpillars are very fragile at this stage, and should not be directly transferred from leaf to leaf. The leaf should be carefully cut around each larva and transferred that way. They will eventually find their way off the small piece of leaf and onto the new food. It is possible to rear lepidoptera all the way to adulthood in closed containers, but it's not the best way. Lack of air flow and high humidity can make the larvae sick, and kill them. I have seen some sort of black infection start growing on the skin of Sphingicampa larvae when they were kept in plastic containers for too long.
Whenever I feel the time is right, I move all the larvae into new homes. I use either 5-gallon plastic buckets or large translucent plastic storage boxes, the kind you can get at the local megalomart. Chuck the lids or put them in a closet. It gets a little easier at this stage, because I use plant cuttings in vases or bottles of water instead of plain old leaves. Using this method, the foodplants will stay fresh for a couple of days up to a week depending on the species of plant. I put a little "miracle-gro" plant food in each bottle too... it seems to help keep the plants fresh. One important thing to remember! The caterpillars are still very small, and extremely dim-witted. If they have the opportunity to crawl down the plant stem into the water, they will do it, and they will drown. I use a strip of paper towel wrapped around the stems of the plants(twigs if they are cuttings from a tree, which they usually are) and jammed into the opening of the bottle. This plugs the opening, eliminating the opportunity for the larvae to go for a swim. Once I get the plants and bottles of water set up, I cut a piece of nylon netting to cover the bucket with. This enables constant air flow. I secure the netting on the top with a piece of cord and a small bungee-cord wrapped around the top.
The larvae are extremely fragile when this small, so it is best not to try to move them bodily from leaf to leaf. I like to hold the leaf they are on with tweezers, and carefully cut the leaf out around the caterpillar, leaving a small bit of leaf with the larva sitting on it. I place this on the new foodplant, and the larva eventually finds it's way onto the fresh food. If the larva is sitting on the side of the container, I just deal with it and move it as carefully as possible, scooping it up on a new leaf. Care must be taken if the larva is getting ready to shed into a new instar. They are especially fragile at that time, when the new cuticle and skin is forming under the old. The larva will sit stationary for one or two days on a sparse pad of silk it has spun under itself. It is not always obvious when this is happening for an early instar larva, but it's usually pretty evident for an older, larger larva.
As the larvae mature, they get somewhat less worrisome to take care of. They are always somewhat fragile creatures, and demand attention to detail when kept inside like I'm describing. Most do best in warm, not-too-humid conditions. Don't keep them outside in the desert sun, and don't keep them in a damp dark basement. Make sure they are exposed to at least some sort of light-dark cycle each day. It has been shown that this can affect the hormonal balance in the pupal stage that enables the adult moth to develop and eclose, at least for some species. It won't hurt anything if you leave the larvae in the kitchen with the light on overnight, but don't make a habit of it. Keep the food fresh. If everything goes right, the larvae will stay happy and healthy, and will be ready to spin cocoons before you know it.
Shortly before pupation, the larvae may become "restless." You may see them stop eating, and begin to wander around a lot, leaving the foodplant and doing laps around the bottom of the bucket. This is a sure sign that things have gone OK up until now and the larvae are ready to spin up and go to sleep. Some, especially the larger species, will have a blow-out and "clear their guts" just prior to spinning. Don't be alarmed if you see a puddle of caterpillar diarrhea on the bottom of the bucket at this time. It's normal. This definately happens with Antheraea larvae. I cover the bottom of the bucket with a paper towel when the larvae go into fifth instar. Helps with clean up.
The ideal situation is to be able to "sleeve out" the larvae in their natural habitat on their natural host plant. Sleeving is the process of putting larvae on the branch of a tree outside, and covering the entire branch (or part of it) with a mesh net, called a sleeve. It enables the larvae to live on a live tree, in natural temperatures and conditions, and affords them some protection from predators and parasites. I have no experience with sleeving larvae, so can't make any recommendations. Refer to "Wild Silk Moths of North America" by Tuttle, Tuskes and Collins for info on this method.
A butterfly caterpillar sheds into a chrysalis, most moths spin cocoons and shed inside there, some dig into the ground or under a rock and shed there, but all together this "waiting" stage of life is correctly termed a pupa. The pupal stage is the third of four stages in complete metamorphosis, starting with ova, then larva, then pupa, then imago, or commonly called adult. Fly fishermen are usually very familiar with the term imago, using it to describe adult mayflies. They are one of many kind of insect that undergoes only three stages in life, or incomplete metamorphosis... ova, nymph, and imago. We're not overly worried about that here. Anyhow, the pupal stage is the easiest to deal with when rearing lepidoptera.
There are only a few things to keep in mind with your pupae. Species that spin cocoons are easy. Most will just sit around for a while and then one day the adult will hatch out, or eclose. Some species do require a bit of special treatment. Saturniids that originated in areas where they overwinter as pupae might need to go into the freezer for a while, even up to a few weeks, in order to trigger the hormonal release that initiates adult development(if you want to sound like you know what you are talking about, you would say this freezing is "required to break diapause." Diapause is the period of "inactivity" that occurs in the pupal stage.) I have heard this is true with Hyalophora cecropia. Other species may not need to be frozen. If the species originates from an area that experiences cold weather and they overwinter as pupae, it does not hurt them to be refrigerated for a while. Refrigerators can be very dry places, and they will desicate pupae if just tossed in the frig with your leftovers. I have refrigerated pupae many times for over a week when I knew I was going to be away and didn't want them to eclose while I wasn't there. I put the cocoons in small plastic containers, the same as used for ova and early instar larvae, and stick them in the frig. I haven't worried about lack of air flow, I figure that the pupa's oxygen needs are going to be pretty slight when they're down around 40* or colder. Often times when I bring them back out to room temp they will eclose within a few days.
Another thing pupae need is moisture. If kept in too dry and warm of an environment, they will lose moisture from their bodies and die and dessicate. If I have some that are overwintering, I spray them down good with water every week or so. They don't need to be kept wet to the point they will grow mold. Obviously desert species such as Hemileuca juno, Agapema anona, etc. are more tolerant of dryness than species from the rainforest.
If the pupae naturally occurr where it rains a lot, they've been set up to tolerate some wetness. I routinely hold cocoons under warm running water from the kitchen faucet until the silk is completely soaked and becoming soft. That way I know some of the moisture is going to soak through the cocoon and be available to the pupa. Doesn't seem to hurt them one bit. Next time you have a polyphemus, cecropia, calletta, or some other species that spins a substantial cocoon, after the adult ecloses, cut the cocoon in half and take a look at how it's made... It's surprising to say the least. It took us brilliant humans until a few years ago to make a Gore-Tex jacket that was waterproof and breathable... and insects have been doing it forever.
If the larvae are earth pupators, meaning they dig down underground to pupate instead of spinning a cocoon, they must be supplied with a deep layer of soil, at least 6 to 8 inches, the more the better, to dig into. It's advisable to use damp potting soil. Not mud, and not dust... but moist. DO NOT use soil with "vermiculite" in it... if that is left without being watered for even a short while, it will suck all the moisture out of the pupae and kill them. A friend did this with several species of Sphingiid one year, and had all of the pupae turn into dried out husks. Eacles, Citheronia, Sphingicampa, most Hemileuca, and a few others are earth pupators. Nearly all, if not all, Sphingiids also are diggers instead of spinners.
One important thing to remember is that reared leps usually don't stick to the same schedule as their wild counterparts, unless they are reared under identical wild conditions. This is probably due to a number of factors... Temperature, food, moisture, airflow, air quality, leaving the kitchen light on overnight, living in a bucket instead of the woods, whatever. It's not uncommon to have adults eclose within a few weeks of pupation, even for species that overwinter in the wild. I have also had some individuals experience "extended diapause" meaning they had sat in their cocoons for so long I was getting ready to toss them in the dumpster right before they eclosed. I had one female polyphemus that stayed in cocoon for over 13 months. Some species are well known for this. Folks have had calletta stay in cocoon for four years before eclosing. I have several calletta cocoons right now that are over two years old, and still feel and appear viable.
When an adult ecloses and you find it sitting in the cage, it is the moment that makes all the work worth while. I still remember, so many years ago, the first time I saw a plain, not very attractive tiger moth in a jar where I had kept a woolly-bear caterpillar as a child. It was more or less pale dirt colored, with some dark smudges, but it was the most impressive moth in the world to me at that moment. I had successfully (more or less...) reared through a caterpillar to an adult moth and "Knew What I Was Doing!" Too bad I had multi-year gaps in my interest, well, not interest but intensity of interest.
For the large Saturniids, it is imperative they have enough space in whatever cage they are in to climb up and hang, so they can let their wings expand and harden. It's an amazing sight to see a wet, crumbled up moth with tiny wings and a huge body break out of a cocoon. There is a large amount of fluid in their body. They pump this fluid through veins in their wings to expand and stiffen them. Over a few hours, their wings fully expand, harden, and the fluid dries. This process enables them to have wings which can carry the moth in flight. It's counterproductive if cocoons are stored in a small box, and an adult emerges but is unable to expand it's wings.
What to do with the adults can be a difficult decision... Obviously they can be put into a collection as perfect specimens. Some can be papered and frozen to trade with other collectors who do not have access to the same species. If the timing is right and there is opportunity, a male and female can be paired and a new generation started. One of the best, most interesting things that can be done is to use a new female moth to "call" wild males. Of course the timing and location must be correct! If you have a female Atlas eclose in Illinois in January, you won't call many wild males. It is usually good and perfectly OK to place a few adults or pairs of adults in each collection. Even among siblings there will be slight differences in markings and colorations among individuals.
The best way we've ever found to kill the adults and make them ready to prepare for the collection is to "ZAP" them with ammonia in a syringe. With a quick decisive hand, grab the moth by the thorax when it has it's wings folded. Have a hypodermic needle charged with household ammonia in the other hand, and stick it into the underside of the moth's thorax, and inject a few millileters or so of the ammonia. It instantly, painlessly kills the moth. It also keeps it in a very relaxed state for several hours if you cannot get it on a spreading board right away. This holds true also if the moth is stuck in a glassine envelope and frozen... when thawed they are usually very relaxed and easy to work with. Some collectors I've met use Ethyl Acetate in their syringes, the same stuff used for charging plaster-bottomed kiling jars. It kills the moths as dead as they will ever get, but I've found that it induces a rigor mortis almost instantly. Moths zapped with E.A. are stiffer and more difficult to work with on the pinning board. These are usually pretty large moths, so if they are put into a normal insect killing bottle, they will flop around for at least a short while and they will rub scales off their wings. The injection method is best. See our "curation" page for pinning examples.
Significant casualties can be experienced at any time during rearing, usually with no warning. Caterpillars can get sick and just quit eating and die. Sometimes an apparently healthy caterpillar will puke up a bunch of black gunk and keel over. Quite often pupae will just not develop into adults, but just die. It is very very rare to start out with ten ova and end up with ten adults. Usually several larvae out of any bunch will not make it out of first or second instar. A few more will kick off in later instars for no apparent reason. I personally have not experienced heavy losses in the pupal stage, but others I know have.
If you take as good care of them as you possibly can, keeping them clean, with lots of fresh air, most of them will make it through. My larvae have just suffered heavy losses... I had to leave for an entire week and had over a hundred larvae of six species, mostly in second instar. I gave my wife a crash course in caterpillar care, but over the week most of the foodplant dried out to the consistency of fresh Doritos, and lots of the larvae did too. All of my Hyalophora columbia gloveri perished, most of my luna, a lot of my Actias selene, a few of my oculea, all of my Sphingicampa hubbardi, one of my Eacles oslari(they were in "rest" between fourth and fifth instar, so they were more durable), and thankfully none of the Automeris iris appear to be too bad off. It's a discouraging loss, but it must be kept in mind that they're bugs in the end.... and how many millions of them are splattered on windshields right now? It's still a lot of work down the drain... literally.
© September 2003. All content © Hunter and Joel.