Our goal in producing eggs is not to increase the wild population. That's because captive raised animals are often less able to survive in the wild. Rather, our goal is to educate so people will love butterflies and want to help conserve them.
To supply monarchs to schools, you need from a few hundred to a few thousand eggs. We're dealing with wild animals and nature, so the process isn't entirely predictable or the same, year-to-year.
To produce eggs, you need a number of egg-laying females. You can obtain these by...
- Capturing wild females in mid-August. Females--presumably ones that have mated and laying eggs--are hard to find because they are widely dispersed and hard to capture. Here's my solution. I have a number of Liatris plants that bloom in mid-August, located just outside my office at home. Liatris flowers are very attractive to monarchs; they feed so intently that you can sneak up on the monarchs if your move very slowly and capture them by hand. You may need to check the Liatris flowers numerous times during the day. But if monarch numbers are low, you may not be able to capture enough. And now it's too late to raise more females. So, your only backup option is 3 below.
- Raising your own females. If you can find at least 20 eggs in the wild, you can raise females and mate them with wild males. (Males are much easier to find in the wild and capture.) Or, you can mate the females with males you raised from eggs--but then you need to get eggs from two different places to prevent inbreeding. You mate the males from one location with females from the other location at least 10 miles away. This option may be best if you need monarchs for your programs throughout the summer. You can build up your captive breeding population from relatively few wild eggs. If unsuccessful, you can later try options 1 or 3.
- Obtaining chrysalids/newly emerged females from people in your community by posting your needs online.
Whichever method you choose, you probably need at least 10 females because several may...
- Test positive for the OE parasite and have to be discarded.
- Escape from your breeding tent.
- Become injured or fail to feed themselves.
- Begin laying too late (timing is wrong for schools).
- Fail to lay, because they mature into migratory adults, rather than reproductive adults.
These are the main challenges of captive breeding...
- Securing enough potential breeders
- Feeding captive butterflies
- Producing eggs in captivity after they are normally laid in the wild
- Processing eggs for pickup by teachers
- Communicating with teachers
- Promoting the program (to combat teacher turnover)
I'll deal with each of these in more detail below.
- Finding enough butterflies. You need enough adults of each sex to produce about 5 laying females. Given potential losses due to disease, injury, skewed sex ratios, non-reproductive adults, and escapes, you need to start the breeding effort with at least 20 newly-eclosed adults. Forty would be better. --you can always release surplus butterflies if you have enough laying females.
- Finding non-migratory butterflies. You need eggs in late August or early September, after the migration has started in Wisconsin. In other words, you need to produce eggs a bit later than they are normally laid in the wild. In late August, an increasing proportion of eclosing adults are migratory (non-reproductive). These are not distinguishable from reproductives, so some of the butterflies you capture to breed may never lay..
- Processing eggs for classes. Producing a large number of eggs in a short time strains your abilities to prepare eggs for pickup by teachers. If you have enough laying females, five or more, the females will provide, but you may struggle to keep up.
- Bad weather: A stretch of cold, rainy weather could cause a temporary halt in laying, meaning you may not have eggs when the teachers prefer them.
Timing issues
Timing egg production is perhaps the most challenging part of breeding. Nevertheless, by monitoring progress, staying flexible and having backup plans, I have always been able to provide enough eggs when teachers wanted them.
I aim to secure my breeding adults around August 15. They can be newly eclosed adults or adults you capture when they come to feed on Liatris flowers. This gives you about 3 days to get them feeding themselves and tamed. Then they need perhaps 5 more days to begin mating. Then maybe 5 more days to begin laying. Now the first eggs are starting to appear at the end of August. You may get some sooner if you captured a female on August 15 who was already mature, perhaps even mated.
Because laying in the wild tapers off and ends around August 29, you might find yourself in a situation where you got a lot of eggs early, but none in early September when some schools have asked for eggs.
Ways to extend egg availability into September:
- Raise your breeding caterpillars under artificial lights with a timer set to July daylengths. Make sure they get good-quality food. Make sure the temperature doesn't dip low at night, as happens outdoors as fall approaches. These are thought to be the cues that cause developing caterpillars to develop into migratory adults.
- Extend the life of egg-laying females by handling them gently and avoiding injury.
- Stretch out the egg-laying opportunities for some females. You could isolate them in a mesh cube in a dark and/or cool place (but continue to feed them). This would place them on "hold." A more simple, less drastic solution would be to simply withhold milkweed stems for a few days from all your laying females. But some females become so urgent to lay that, without milkweed, they will even lay on the artificial flowers or on the tent wall.
- You can put eggs in the refrigerator for up to 7 days without much decline in viability. This completely stops progress towards hatching. But make sure there are no freezing spots in the fridge, and make sure the humidity of their container is high. There was only one year when this was needed.
Another aspect of timing is finding out when your teachers prefer to pick up their eggs. Some will want them when classes start, others later. Let them know you will try to honor their preferences but cannot guarantee it.
I create a spreadsheet with all relevant information, then rearrange the schools in order of their preferred pickup dates. This allows me to see if any teachers need to take their orders on a day they don't prefer. I suggest you post on this blog or somewhere convenient when their assigned days are, so you can minimize emails to each school.
Minimizing harms from captive breeding
Captive breeding is known to decrease the health (fitness) of wildlife. There has been criticism of captive breeding of monarchs, especially breeding for commercial purposes. To maintain the trust of the scientific and conservation communities, it's very important we do everything possible to minimize the potential harms of captive breeding:
- Inbreeding,
- Spreading of disease,
- Loss of fitness when released back to the wild, including loss of ability to migrate.
Inbreeding (loss of genetic diversity.)
If you capture wild females, you can assume they mated with an unrelated male, so inbreeding won't be a problem. But wild females may be very difficult to capture.
If you raise your laying females from eggs, you can mate them with wild males, which are much easier to capture.
If you mate hand-raised males with hand-raised females, there's potential for inbreeding. You have to assume that all eggs laid in one location are from the same female--hence these eggs are brothers and sisters. So, to prevent incestuous matings, you need to get eggs from two different locations at least 10 miles apart, and raise these eggs separately
When they eclose, make sure your butterflies mate with one from a different location. One tent has all females from Location A along with males from Location B. A second tent contains the opposite. You might need a third tent for females that have mated two times or are laying. (Mating more than two times may be harmful, and amorous males can interfere with laying females.) If you have sourced your eggs from many different locations, keeping separate lines may not be necessary.
Spreading disease
The most important way to avoid spreading disease is to test laying females for the OE parasite. Release any that test positive. Possibly euthanize any that are heavily infected. Test them as soon as you see them begin to lay--this saves you the time of testing all females, because not all are going to lay.
Our caterpillar rearing method minimizes disease. But to demonstrate this, you need to keep records of all instances of possible disease. Some caterpillars just disappear or die of unknown causes (perhaps injury from handling). It's helpful to know your absolute success at each stage: how many eggs, how many hatchlings, how many small caterpillars, how many large, how many "J's", how many chrysalids, and how many healthy adults.
Keeping these detailed records (and calculating % for each transition) is burdensome and you might do it only on certain occasions. For example, it would be a good exercise for students or campers. Or if you have poor overall survival, you will want to know at what stage the problem occurs.
But for clear cases of disease, you should definitely keep records (with a description of the malady) and calculate a rough % (rough because you may not know the denominator--total number of caterpillars--precisely).
Examples to record would be discolored caterpillars (especially black), caterpillars parasitized with tachinid flies (pupae hanging on strings), eclosed adults with OE (suspect this if they are weak or discolored), caterpillars that stop eating or waste away (possible pesticide contamination).
Loss of fitness through selection of traits that adapt to captivity.
This probably isn't a danger when we only raise one or two generations.
Loss of ability to migrate because of rearing indoors.
Loss of ability to migrate because of rearing indoors.
A scientific paper claiming this outcome has been widely reported in the press; people often mention it when you display monarchs.
I have read this report, and do not think its conclusions of migratory loss are supported by their data. In any case, the majority of caterpillars we raise will not be released as adults to migrate. Finally, our goal is not raising butterflies to augment the wild population. Instead, our goal is to advance monarch conservation through education.
How to obtain your breeding adults
- Starting about August 15, pick wild males and females off liatris flowers while they are nectaring. Find a garden you can observe and access often during the day. If you sneak up moving VERY slowly, and if possible keep the flower between you and the butterfly (blocking its vision), you don't even need a net. It's very important is to position your thumb and forefinger with the wing inside the gap of your fingers before you quickly close them. In other words, don't lunge the last few inches then snap your fingers shut, because the butterflies will react to the sudden motion and dash away before you can move those last few inches. A small garden attracts with both flowers and milkweed attracts more females. Large masses of flowers tend to attract mostly males. In 2023, this worked beautifully. But in 2024, there were not enough butterflies passing through. I was only able to catch one female this way.
- Go to a place like a small prairie in town (the Odana Golf course prairie) where you see many monarchs flitting about. The problem is, 80-90 % of them will be males, because places where you notice butterflies are places males go to pick up females. It's difficult to catch monarchs with a net, because they are very fast and alert. With practice, you can get reasonably good at using a net. But it's not efficient, because you can capture maybe one every half hour, and they are mostly males.
- Produce butterflies from eggs you find earlier in the season. It takes about a month to go from egg to eclosed butterfly. Plan so butterflies emerge Aug. 15-20. If you produce butterflies for summer programs, this meshes perfectly with August breeding. If you need to adjust timing, you can slow down development by reducing the temperature where caterpillars or chrysalids are kept.
- If methods 1-3 fail, put out a call on social media for donations of chrysalids or caterpillars from other butterfly enthusiasts in your area.
- You can purchase chrysalids from commercial breeders.
The breeding tent
Place the tent where it's protected from wind. Shade or dappled shade is better than full sun. Best, if possible, would be to place it where it goes into shade during the hottest part of the day. Place it on grass (for your comfort), firmly staked to the ground. Move the tent roughly every 2 days to prevent killing the grass.
If you want a place where visitors can walk inside to experience butterflies, then you need something larger, like the kind of mosquito tent that goes over a picnic table.
Marking butterflies
If you mark your butterflies, you can give them individualized care, ensuring that each one feeds daily. It helps you predict which ones will lay eggs and otherwise manage your breeding females.
Use a sharpie permanent black marker. I'm right-handed, so I hold the closed wings with my left thumb and forefinger, then write the number on the underside of the right lower wing. By always marking the same place, I know where to look on the butterfly for the number. If by mistake the number isn't legible, simply write it again nearby.
Training newly emerged adults to feed
The secret to breeding is feeding. Feed butterflies a solution of 20% honey water (1 part honey to 4 parts water). Link to details.
You can't feed butterflies on cut flowers because you don't know how long the nectar will last after cutting. Instead, I use an "artificial flower," consisting of a plastic scrubbie placed in a plastic bowl just large enough to hold it. You dribble honey water over the top of the scrubbie; it does not work by wicking up the solution from below. The solution should be given in the morning and refreshed in the afternoon; if many are feeding, refresh it more often. The scrubbies and bowls should be cleaned every other day.
Use at least 4 artificial flowers per tent, each sitting in a saucer with water to discourage ants. Mix the honey and water in a floral tube, eyeballing a mixture of one part honey to nine parts water. Heating the mixture in a microwave for 5 seconds warms it enough to allow mixing the solution by turning the tube upside down multiple times. Place the floral tube in in a Yoplait yogurt container to hold it upright, along with some Q-Tip's. Let the solution cool (perhaps with an ice cube in the Yoplait container) before feeding.
When an adult ecloses, let it harden its wings for at least 4 hours. You can start training it to feed the day it ecloses, but usually they are not hungry till the following morning. They can be conveniently kept in a mesh cube while wings are drying and until you are ready to begin training to feed.
When feeding, it's important not to excite the butterflies. If they do get too excited (lots of fluttering), let them calm down before proceeding. Placing them in the dark is a quick way to calm them.
Butterflies taste with their front feet. (Actually, these are the middle feet--the front ones are small and folded out of sight up against the body.)
- When you touch the moistened Q-Tip to a front foot, usually they will stick out their proboscis and begin feeding. First, I try to touch the Q-Tip to its foot when the butterfly is inside the cube and the Q-Tip is outside--so it can taste the honey through the mesh. This method disturbs them the least, but often as they move around inside the cube, thier foot never makes contact with the honey.
- If #1 doesn't work, I hold the butterfly with my fingers, wings pinched together and offer honey to the butterfly outside the cube. Since the butterfly wants to find something to stand on, it will grasp the Q-Tip, tasting the honey. If you keep trying, there's a 70% chance it will stick its tongue out and begin to feed. Success! As soon as it starts feeding, it quiets down--place the butterfly clinging to the Q-Tip back in the mesh cube and let it feed to satiation. You have now trained it to recognize a Q-Tip as food. The next time you offer a Q-Tip, there's a 95% chance it will begin to feed.
- About 10-20% will not begin feeding by the foot-touch method. For these, you can hold the butterfly sideways and insert a straight pin at right angles into the loop of the furled proboscis. Then very gently move the pin away from the head. This will extend the proboscis down to the Q-Tip you or someone else is holding just below the butterfly's head. Most of the time, when the proboscis touches the Q-Tip, it will begin feeding. Again, you may need to let it calm down if it becomes too excited.
- If #4 fails, the last resort is to put a fragrant, freshly picked flower very close to the butterfly while you perform steps 2-4. Or you can dribble honey solution onto the flower and place the butterfly on the flower.
Once trained to the Q-Tip, your next step is to train each butterfly to the artificial flower, a much easier job than above. Once butterflies have fed from Q-Tip (as above), place them in the breeding tent.
When working with butterflies in the breeding tent, always move with slow and deliberate motions. This avoids exciting them, which...
- Promotes taming,
- Prevents disruption of feeding, mating, or egg-laying,
- Prevents injury.
The following morning when you enter the tent, offer each butterfly in turn the Q-Tip while they are clinging to the side of the tent. Once they extend their proboscis, try to get them to put all 4 feet on the Q-Tip. If you are careful and persistent, they will gradually let each foot go from the tent and transfer it to the Q-Tip. Gradually move the Q-Tip further from the tent wall as more feet transfer. This is a bit time-consuming but fun for children and volunteers.
Once on the Q-Tip, slowly transfer the butterfly to an artificial flower. Don't make any sudden or jerky moves. Leave the Q-Tip (with butterfly) on the flower. While feeding, butterflies move about--within a few minutes, they will begin feeding on the flower rather than the Q-Tip. Let the butterfly remain undisturbed until he is satiated.
You can fit 3-4 butterflies per flower. If more, they will disturb each other and stop feeding before they learn the flower means food. You need enough artificial flowers to avoid crowding. After 2-3 days (sometimes only 1 day!), many of your butterflies will fly to the artificial flower to feed without your assistance.
The butterflies also become tamed--scientists say "habituated" to of humans--even if you captured them in the wild. You'll notice that some have distinct personalities. Some are not as tame as others and continue to become excited when you enter the tent.
You will often see the butterflies flying against the tent walls. But this is not necessarily fear. Instead, it's an expression of their need to move about and explore their environment. For all we know, when they are flapping against the tent, they imagine they are up in the sky flying to the next patch of flowers.
Daily care of the breeders
The butterflies should be fed twice a day, in the morning and afternoon (precise time isn't important). On each visit, you note if any are feeding by themselves on the artificial flower. For those not self-feeding that day, you offer each one a Q-Tip and transfer it while feeding to the artificial flower. Make a note (GF for "good feed" if they feed for a minute or more.) You don't leave until all butterflies have a GF notation. The more trained they become, the faster you can get them on the Q-Tip and transfer them. The point of the daily Q-Tip routine is to assure that all are being fed. You might omit this routine to save time--but that runs a small risk that you will end up with a neglected and starved butterfly.
Make a note of any that fly on their own initiative to the flower, or if you see it resting on the flower when you first enter the tent (FF=flies to flower). If you've seen one do this several times, it's likely the butterfly is capable of self-feeding and perhaps you can omit the Q-Tip routine for that individual. Another sign a butterfly may be self feeding is if it "pees" (sheds a drop of liquid from the tip of it's abdomen) after you enter the tent, but before you feed it. Butterflies usually pee about half an hour after feeding.
Every year, I find a few dead butterflies in the tent. Some have no signs of previous weakness--but many do show weakness before. I assume that some of those deaths are due to starvation of butterflies that somehow don't self-feed or somehow got overlooked during the routine visits.
The two daily visits provide an opportunity to take useful notes on each butterfly:
- Is it feeding?
- What condition? (noting weakness, broken wings, or injured legs/claws).
- Matings (record the numbers of the male and female).
- Developing sexual behavior in males. This includes showing aggressive behavior or interest in the females, or aggression towards other males.
- Developing sexual behavior in females. Before laying, a female tests whether the plant is a milkweed. She does this by striking the plant rapidly with her normally hidden two front feet. This drives sensors on her front feet into the plant, tasting it to see whether it's milkweed. Begun as soon as she lands on the milkweed, it's a very rapid, fanning motion that might otherwise go unnoticed if you don't look for it. I call this behavior "karate chop," or KC.
These records allow you to make sure all are feeding and assess progress towards egg-laying. Before females can lay, they first must mate and show KC a few days before the onset of laying. For a complete list of the observations needed and symbols, go to the Records page.
Weather and other hazards
With temperatures under 70 F, the butterflies are less active and have less need for feeding. If it's rainy, or very cool, the butterflies will be entirely inactive. You can omit one feeding, but it's good to renew the artificial flowers at least once a day during bad weather. Very hot, sunny weather can cause hyperactivity, leading to death by dehydration. If sunny and over 90 F, consider a third feeding and/or misting the tent on the inside, so butterflies can drink. Spraying the outside will cool the tent.
If rain is expected, consider putting the rain fly on the tent. After rain, use a sponge or towel to remove water that has pooled. If you don't remove water promptly, some butterflies might drown--usually these are ones that you recorded as weak previously. If severe storms are forecast, move the whole tent indoors, even if you have to partially compress it to move through doors. I have had tents blow away with butterflies, tumbling over and over. Luckily, none died.
I had one tent ripped open by a raccoon that ate every butterfly inside. Luckily, it was the tent with males. If you have a raccoon problem (raiding trash cans?), beware. Chipmunks may also eat butterflies.
Mating
Your butterflies have been feeding and getting tame for a week or so--now you are beginning to lose heart that they are really going to breed. But when you enter the tent one day, you are surprised to see two mating. They will remain together for up to 18 hours, perhaps into the night. Be sure to record their numbers. Try not to disturb them.
If other butterflies that are milling about, disturbing them, move the pair to the top of the tent where there's less commotion. Disturbance might lead to their separation, though this is uncommon. It's a judgement call: is the disturbance you cause by moving them worse that the disturbance from other butterflies?
To move the pair, you can offer a Q-Tip to the male to cling to, then transfer both together to a place where he can get a good grip away from the others--for example, to mosquito netting at the top of the tent.
Once they are situated in an undisturbed place, you can touch a Q-Tip to the female's foot. She will extend her proboscis and begin feeding. Usually, you can get her to grab the Q-Tip with a leg so it dangles from her claw, while she continues to sip. You can also try to feed the male the same way, though it's less necessary. Sometimes he can be fed by placing a Q-Tip on the outside of the mosquito netting and holding it there with a pin.
In nature they do not feed while mating (to my knowledge). But we can feed them to be sure they remain healthy--especially the female.
Once butterflies have mated, we know they are reproductives--and not migratory butterflies.
Once there has been a mating, I place a milkweed stem in the tent, held upright in a jar with water and a lid. I place the jar on a small board, so it won't tip over. This allows you to watch for "karate chops" and egg-laying.
What to do with mated females
Females often mate more than once in the wild. In the tent, they may mate up to four times. Multiple matings are probably beneficial to females, because the male passes a packet of food along with the sperm. But too many matings--which are possible in captivity--could be harmful. I've observed females that mate multiple times seem to get enlarged abdomens--perhaps they become engorged by too many packets of food. Some of these engorged females are unable to lay, though they repeatedly try to.
Too many matings also remove a female from egg-laying duty, since mating takes up too 18 hours. Sexually aggressive males can distract laying females from feeding or egg-laying.
To prevent these problems, move females that have mated twice to a separate "maternity tent," This segregation may also prolong the life of the female by lessening buffeting from other butterflies. Keep the mated males with the unmated females.
Mated males can be kept with the unmated females. You know they are reproductives. Some of your other males may be migratory butterflies, useless for breeding.
Males that are too aggressive, or who have mated several times (and are bothering the laying females), can be released if you have enough males.
Preventing escape
Once mated, a female becomes very valuable. Even more so when she begins to lay. Take precautions to ensure she remains safe and especially that she does not escape.
Butterflies are attracted strongly to light. They will fly towards light or will cling to the sunniest side of the tent. Correctly orienting the door helps to avoid escapes, because they will tend to stay on the side away from the door. So it's very important to face the tent's door away from bright things. This means, in most situations, face it to the north. But there are other things that determine brightness besides sun direction--such as an opening in the canopy for a shady tent location, or presence of a nearby bright object.
With your door correctly positioned, you still have to be very careful that no butterflies are clinging to your hat or back when you leave the tent. This is how I have lost the most--even laying females! To combat this, have a partner who inspects your head & back and helps you exit. A partner can help you balance when you exit through a door that's mostly zipped shut, and to zip it behind you as you pass out. You might text or radio your partner when you are ready to exit.
Finally, there's the occasional sly butterfly that makes a fast dash for the door. As you try to enter or exit. They are smarter than they look. The partner can try to deflect them as they make their dash.
Keep a net nearby in case one does escape. Try to recapture it before it goes too far or watch to see if it lands somewhere within reach.
Tents are more or less valuable depending on how their doors work. One that zips from the bottom is better, because you can crawl out at a low level--butterflies are more likely to escape at a higher level.
A tent with a door that hangs naturally in a closed position when unzipped is better than one that hangs fully open when unzipped.
Egg production
Females do not begin to lay until about 5 days after the first mating. Once females begin to lay, I place a fresh milkweed stem in the tent each day. I remove the stem from the previous day and immediately label it with the date eggs were laid. Don't get milkweed sap in your eyes.
Females usually start laying a few days after they show the "karate chop" behavior (KC). The number of eggs laid ramps up for a few days and reaches a maximum. Now you need to assess if you will have enough eggs on the dates needed. Because of possible injury or escape, always have a few more laying females than you need.
Adult, reproductive monarch females live from two to eight weeks. According to Karen Oberhauser, the largest number of eggs she saw laid by a captive female was 1179. Captive females lay about 700 eggs on average, up to 205 in one day.
You can manage egg production by matching supply and demand. Slow egg production by...
- Removing the milkweed stem (see below).
- Removing one or more laying females to a dark place (by placing them in a mesh cube in a closet).
Options if you have more than enough laying females...
- Release the oldest or most infirm so they can lay in the wild.
- Give a laying female to a school with experienced teachers and many classes (saves you work.)
- Set up a display of laying for the public.
Check the milkweed several times a day. When you think you have enough eggs, simply remove the milkweed stem from the tent. Label it with the laying date, then hand it over to team members who will count eggs and label the stem (or individual leaves) for delivery.
Watch for eggs laid on the scrubbies or walls of the tent, or for eggs fallen to the floor. Pick them up with a tiny brush, and move them to hatch in an ice cube tray.. Many of these are viable. If you check for these eggs and collect them daily, you know when they are laid.
The biggest problem causing cessation of laying is that laying females get worn out, especially their wings, legs and claws. Injury to legs and claws can occur when you pull them off the mosquito netting of the tent, so always do this very gently. A tent with less area of mosquito netting is a better choice.
Females with damaged legs or claws are unable to perform the acrobatics necessary for laying under a leaf. But you can still get eggs from them. Use your finger to help them get into the proper position for laying. If more severely disabled, or if they can't fly, you can place a milkweed leaf on the floor of the ten, then place the female on the leaf.
Factors influencing egg production
In previous years, once I had females producing eggs, they produced steadily.
But in 2025 when schools started, we had a stretch of cool and cloudy weather lasting about a week. Daytime temperatures were around 60-65 F. Laying completely stopped, both for myself and for the Aldo Leopold Nature Center. Below is a summary of information from CoPilot AI (blue text) and my own experience. You may be able to use this information to enhance egg production. At first, I wondered if the females were just taking a rest after laying a substantial number of eggs. So, I asked AI...
What influences egg-laying intervals?
- Egg maturation: Females don't lay all their eggs at once. Eggs mature gradually inside the ovaries so females will have natural spacing between bouts of laying. But there is no definite rest period after laying a hundred eggs.
- Milkweed availability: Females are highly selective and will delay laying if suitable milkweed isn't available. They use chemoreceptors on their feet to test plant quality. If they don't find good quality milkweed, they may hold onto mature eggs for hours or even days.
- Environmental conditions: Temperature, humidity, and photoperiod affect both egg development and female activity. Hot, dry conditions can slow down laying rates.
- Energetic demands: While monarchs don't "rest" in the same way we do, they do need to feed regularly on nectar to maintain energy levels. If nectar sources are scarce, or they skip a feeding, egg laying may slow down.
- Age and senescence: As females age, their egg production may taper off. Some die with unlaid eggs in their bodies.
Summarizing, if females are healthy and well-fed, not injured or old, and if they are presented with good quality milkweed to lay on, then environmental conditions (including conditions of captivity) can influence egg-laying. Let's explore some of these conditions...
Temperature: Monarchs are strongly influenced by temperature in all their activities. At first, I positioned a heat lamp (250 W, yellow tint) close to the tent while outdoors. Some butterflies were attracted to the lamp, and a few apparently basked in the heat, but there was little increase in activity and no laying. For the night, the majority of butterflies roosted on the side of the tent away from the heat lamp.
I decided to move the tent indoors where I could increase the thermostat. With a setting of 75 F and a heat lamp, the temperature in the tent was about 77 F. Now the butterflies were much more active: more fluttering and a few flying very fast around the tent. On the first day indoors, I got only 5 eggs.
Part of the problem seemed to be females not finding the milkweed plant. The fast flying, along with resulting collisions, suggested the butterflies could not see well in the stark light of the heat lamp.
So, I moved all the females to two tabletop tents where they remained within a foot of the milkweed stem at all times. I think being close to a window with natural light also helped (though now there was no heat lamp). Immediately, egg production increased to 39 and 15 from two females in one day, and continued on the following days.
The social environment can also affect egg-laying. When several females are housed in the same small container, bouts of fluttering might "wake up" inactive females and stimulate laying. Several females laying at the same time don't seem to interfere with one another. Mating, however, can prevent a female from laying for 18 hours, so moving males to another tent is recommended.
In summary, during cold weather, these actions returned egg production to normal levels...
- Bringing butterflies indoors and setting the thermostat to 75 F.
- Confining them in a small tent close to milkweed.
- Placing the tent close to a window.
Counting eggs
We count eggs to...
If your milkweed leaves threaten to dry and curl up before hatching, you should cut the eggs off the leaf, creating tiny squares of leaf with an egg on each square (photo). Put one egg in each compartment of a white ice cube tray, then balance the tray on a wine glass. Place the wine glass base on a saucer of water, creating a moat to keep spiders out. You can balance (crisscrossed) multiple ice cube trays on one wine glass. Check the ice cube trays every few hours--hatched caterpillars are easy to see walking around the white trays. Transfer caterpillars to a fresh milkweed stem with tender leaves. As you transfer each one, make a tick mark on a data sheet--to count the total hatched.
- Keep track of overall breeding success.
- Measure the laying progress of individual females.
- Determine if we have enough eggs for upcoming demand.
- Facilitate distribution to schools and subdivision of eggs among teachers at a school.
The "leaf diagram" helps you accurately count eggs, leaf by leaf. It's time-consuming, but you can use young volunteers to do the counting.
It's essential to have a small but bright flashlight, holding it so the eggs cast long shadows. Aphids or sap balls often look like eggs. When in doubt, use a hand magnifier. Illuminating the egg from several different angles as you move the flashlight helps.
- Make a blank diagram on a small piece of paper.
- Use a sharpie to number the top surface of each leaf: 1R for bottom tier of leaves, right side; 1L for bottom tier, left side.
- Count the eggs on the top of leaf 1L.
- Count the eggs on the bottom of leaf 1L.
- Continue with leaf 1R, and then one by one all the leaves above it.
- Add all the eggs on each tier and write the number on the far right. For tier 6, the total is 14.
- Add the totals of all tiers and write the total at the bottom right, 18.
- Count any eggs on the stem and add it to the total.
- Add the date the eggs were laid and the expected hatching date, 4 days later.
The diagram helps with distribution
Now that you know exactly where the eggs are, you can give each school a portion of the milkweed stem that most closely matches the number of eggs they want. If they ordered 10 eggs and there are 14 eggs on the top tier, just cut off the top tier (by cutting the stem just above where the leaves for the tier below attach to the stem). Place the stem with tier 6 in a new jar with water. Then cut the leaf diagram on the line between tiers 5 and 6 and tape this fragment to the new jar. Add a second label to the jar with any missing information, such as the date of laying, and the name of the school the eggs are for.
The remaining original stem now has only 5 tiers with a total of 4 eggs. You can designate that stem for another school, adding a second stem to bring the number of eggs up to what they want. To save jars, put a second hole in the lid so the jar can hold two milkweed stems. If you can't easily give the exact number of eggs a school wants, then give a few more. A few eggs are inevitably lost by bumping the jars during transport.
When teachers at one school subdivide eggs for each class, they can use the diagram to decide what part of a stem, or which leaf, to give to each teacher. Each teacher's container should have a label indicating how many eggs were provided and when they are expected to hatch.
The diagram helps determine hatching success
If you allow eggs to hatch on the stem, you can measure the % of eggs that hatch simply by making a new diagram of the stem, this time showing caterpillars on each leaf (top and bottom). Dividing the number of caterpillars found by the number of eggs provided gives % hatching success.
Actual example: Female #3 laid 37 eggs. Four days later they hatched. When I made a diagram of tiny caterpillars after all hatched, I found only 30 caterpillars. This gives a yield or hatching success of 81%, or a loss of 19%. Two eggs apparently didn't hatch, 5%, and I saw two caterpillars that were larger than the rest; these may have cannibalized some of their siblings. When I misted the stem, I saw two caterpillars rappel an inch down from a leaf, but then they climbed back up the silk again. I checked the countertop for any wandering caterpillars, but they are so tiny they would be hard to see. So with this setup, it's hard to estimate the rate of escape. For a more accurate measure of escape, you'd need to put the jar in a large white bin, where it would be easy to see any caterpillars not on the stem.
Alternate method of hatching and counting eggs
This method reduces cannibalism, because each egg is in its own compartment and you transfer them soon after they hatch. It's still possible for caterpillars to rappel on silk down to the tabletop and get lost if you leave them on the tray more than a few hours. I wouldn't expect to lose more than a few this way.
Pickup of eggs by teachers
Once laid, you have 4-5 days to get the eggs to teachers before they hatch. A little wiggle room.
How-to instructions we provide, or blog articles, explain to teachers what they need to do when they receive eggs. When they pick up, make sure they know what to do next. This is a critical time for them.
Depending on the number of eggs received, there can be hours of work for the teachers to divide the eggs among the various classes and transfer eggs to ice cube trays or freshly hatched caterpillars to fresh, tender stems.
It would be helpful to teachers, if you have time, to email then with news of when hatching is expected, and whether they need to transfer caterpillars immediately. If the stem with eggs on it is already drying out, then caterpillars need to be transferred as soon as they hatch. It's essential that the leaves on the plant to not curl up before they caterpillars can be transferred. If the leave may curl up before hatching and/or transfer, then the solution is to cut the eggs off the leaves and put them into ice cube trans. Help the teachers decide how to handle this.
When to release breeders
If a male or female show no signs of reproductive behavior (matings, aggression in males, KCs in females), and you have sufficient butterflies more inclined towards reproduction, they should be released. After all, it's possible they are migratory butterflies. Likewise, a male that has mated several times can be released, if you have enough other males that have mated fewer times. Early release helps to reduce our impact on wild populations. Another cause for release is weakness--thank them for their service, place them on a flower, and saygood bye.
Communicating with teachers
This is an important and distinct job for one member of the Monarch Team.
Since there's a high turnover of teachers at each school, you need to have a way to recruit new teachers, otherwise the number of classrooms you serve will wither and die. Important forms of communication...
- For Madison's school district, there are newsletters sent to each teacher, and another newsletter to principals. You need to get these announcements to the newsletter editors (in their hands at least 5 days?) prior to the teachers first day at school in August. I'm not sure how other school districts communicate. Write the brief press release for the newsletter and find the email addresses where to send the announcement 10 days before teacher's first day in school.
- Your organization should be able to reach many new teachers. Have posters that teachers will see when they come with their family. Post notices on your website and other communications.
- Advertising a workshop would be an ideal way to recruit new teachers and add new schools.
- Poster at library.
- Be creative... notices on Nextdoor.com. Contact PTAs. Reach teachers through letting parents who come to the Nature Center know about the opportunity.
Most of the teachers at our regular schools are already trained, or if they are new, they are trained by experienced teachers. For new schools or school districts, we probably need to provide workshops for teachers. David can conduct workshops (if he's available, and if ALNC schedules them. A workshop might last 1 or 2 hours.
Many of the regular schools know the drill. It's important that we deal with only one teacher per school; that teacher will place the order, schedule the pickup, and make (or delegate) the pickup. But often teachers at a new (or "marginal" school) will contact me individually. This can cause a lot of confusion and wasted emails. I respond to them that our policy is that one teacher must do the coordinating. Sometimes, a teacher steps up. Other times, they don't want to take responsibility, and that school drops out.
By nature, teachers are busy and sometimes a bit "scattered." They send very short emails with incomplete information. This forces you to respond with questions. It may take many emails and wasted time before you can even select a definite pickup time. Typical exchange: Me: "When will you be picking up?" (They should have stated this on the order form.) Teacher: "September 5." Me: What time?" Teacher: "After school." Me: "Exactly what time, plus/minus 15 minutes?" You get the drift. I have tried to combat this with polite reminders on the blog, or in email responses.
Many teachers need support... for example, a volunteer who will bring in milkweed, wash it, and feed the caterpillars. Several schools in Madison have parents who do the recruiting of new teachers, pickup of eggs, and delivery of milkweed, etc. I'm grateful to Mischa Wagner at Thoreau ES, Melissa LeBlanc at Lowell ES, and Amy Callies for Middleton-Cross Plains. Many teachers want to have monarchs but feel overwhelmed by their situation.
There is a huge variation in the abilities and knowledge of teachers. Some regulars get 100% survival from egg through eclosure. Others lose all their eggs through negligence, such as leaving eggs to hatch over the weekend with no supervision. I overheard one teacher, when kids came out to release butterflies, say: "Don't touch those butterflies. If you do, they'll die."
Many teachers like having monarchs because it rivets the attention of squirrely students just returned from summer vacation. But I suspect many have little interest in monarch conservation--either educating about it or taking action. We need to develop a plan to combat omission. I could fund a contest for the best conservation project by a teacher, with several second prizes.
When a teacher has high mortality, to help them it's important to learn all the facts while they are fresh. Often, it's possible to figure out the cause. Frequent causes of mortality are food contaminated with pesticides, failure to mist frequently, OE or tachinid parasites, dropping caterpillars while transferring them (you must wrap their silk line around the back of the leaf you are transferring them to), throwing out small caterpillars with the old food stem (which happens when you allow the old food to get too dry and curl up), and allowing eclosing adults to fall to the bottom of their cage (without providing paper to climb back up).
Sterilizing equipment to prevent disease
Use household bleach (usually 5.25 %), which is sodium hypochlorite. Do not use the bleach safe for colored items.
For hospital grade disinfection, use a 1:10 dilution, which is 1.5 cups bleach per gallon of water. Allow at least 1 minute of contact time. Rinse thoroughly, since bleach residue produces fumes which could irritate or harm caterpillars.
For safety, use with ventilation, and never mix bleach with ammonia or vinegar, which produces toxic fumes. Avoid using bleach on porous surfaces, natural stone, or metals which can corrode.
Sterilize any container that contacts butterflies before allowing caterpillars to contact it. Sterilize containers used for raising caterpillars periodically, and especially after you observe signs of disease.
Equipment needed for breeding
The numbers of items are the quantity I use. You may need multiples of some items like nets, flashlights, scissors, and brushes if you are involving volunteers or campers.
- Two-person tent (from 1-3 are needed, depending on your method). We have a used one available for $20.
- 8 plastic scrubbies, per tent, used to make "artificial flowers."
- 4 small plastic dishes, per tent, same diameter as scrubbies, used to make artificial flowers. Both the dishes and scrubbies are available from Dollar Tree.
- 1 saucer for each "artificial flower" (filled with water to deter ants).
- Q-Tips. Used for feeding butterflies prior to release (and at least 4 hours after they emerge).
- 1 pint honey in squeeze bottle.
- 1 cup to hold Q-Tip's and floral tubes holding honey.
- 2 boards ~5 x 18 in. on which to place the flowers and jar holding milkweed stem (otherwise they may be tipsy on uneven ground).
- Paper towels to mop up any spilled honeywater, preventing ants.
- Small towels to mop water after storms.
- 1 butterfly net.
- Plant mister, used to help clean up spilled honey or mist inside of tent on hot days.
- Fine scissors for cutting eggs from milkweed leaves.
- White ice cube trays (from Dollar Tree or Target), possibly 12.
- Wine glasses, several You can balance numerous ice cube trays on one wine glass.
- Saucers for wine glasses and for bottles holding milkweed stalks with eggs waiting for pickup.
- Small, bright flashlight for counting eggs.
- Tape, clear, for attaching labels to jars.
- Glass jars with metal lids for holding milkweed stalks. You need 1-2 jars for every school. served. Can be a variety of sizes but the squat, wide size typically used for salsa is best, 3.3" diameter, 4" high. Up to 8 roundish stones added can help center the stem and avid tip over.
- Brushes, tiny, watercolor. As many as you may have volunteers transferring tiny caterpillars.
- 1 dull, short knife for stabbing an X in the metal lid of jars.
- 1 file, circular, for metal, with tapered tip, about 1/2" in diameter, for finishing the hole in metal lids.
- Cubes of mesh, 1 foot square, one face with transparent vinyl, another face with zipper opening. Used to show, retrain, or transport butterflies or chrysalids.
- Sharpie black marker with pointed tip for writing numbers on wings and on milkweed leaves.
- Clipboard for recording data in the breeding tent.
- Floral tubes, 3.5" x 3/4" diameter. At least 1 for each tent.
- Bleach, sodium hypochlorite, 5.25 %, diluted 1:10 or 1.25 cups per gallon of water.
- Straight pins for extending butterfly proboscis or for pinning a date label next to a chrysalid.
Equipment for display of monarchs
- LED lights you can flexibly direct, with a stand or clamp.
- Aligator clips, coat hanger wire, and 2x4 board for making display of chrysalids.