Moths and Butterflies of New Zealand Trust Pūrerehua Aotearoa

Monarch butterflies all over the world are infected with Ophryocystis elektroscirrha or Oe. It is a protozoan parasite that is a monarch specialist. The hardy parasite forms spores on the exoskeleton (or effectively ‘skin’) of adult monarchs. Spores are clustered among the butterfly scales and concentrated mostly on the abdomen.

When infected female butterflies lay eggs on milkweed such as swan plant, parasite spores are transferred to the eggs and milkweed after which they are consumed by early instar caterpillars.
The spores then open in the gut, and the parasites penetrate the gut wall.

During the late larval and pupal stages the parasite undergoes asexual and sexual replication and when the adult butterflies emerge from their pupal cases they have a new generation of parasite spores on the outsides of their bodies. Oe causes considerable harm to monarchs, reducing pre-adult survival, adult body mass, mating ability, fecundity, flight ability, and adult lifespan.

Caterpillars that are infected with a single parasite spore can metamorphose into adults carrying over one million spores!

Unfortunately, there is nothing that can be done to cure or fix butterflies suffering from this disease. The only way to stop the parasite is to ensure food plants do not become infected with spores, which is almost impossible for plants maintained outside. A healthy-looking, but infected butterfly flying in from your neighbour might introduce the parasite.

If you rear caterpillar in greenhouses or cages you could try to ensure any females that are used to lay eggs have no pathogens. It is possible to decontaminate cages and other equipment by soaking them in a 10% bleach solution.

The healthiest monarch butterflies have been thriving without our help for millions of years. Overcrowded conditions are not seen in nature. Saving unhealthy caterpillars and butterflies is not helping monarch butterflies.

Don’t love your butterflies to death!

Thanks to an excellent study at the School of Biological Sciences, Victoria University of Wellington, we are now better equipped to help monarch butterflies. Early in 2020 Dr Phil Lester and Mariana Bulgarella at the School of Biological Sciences, Victoria University of Wellington investigated how many monarch butterflies in NZ carried the parasite Ophryocystis elektroscirrha, commonly referred to as Oe.

This parasite is part of the monarch’s ecosystem. It’s as much a part of the monarch’s environment as fleas are to a dog. It only infects monarch butterflies and while it can kill or weaken them it harms nothing else. Cells were taken from 408 adult monarchs, from locations between Otago and the Far North. Sampling did not hurt the butterflies.

Surprisingly, almost all butterflies from warmer areas of the country, such as Northland, Auckland, Bay of Plenty and Nelson, carried the parasite Oe.

However, the results from the research raised one very big concern: people trying to ‘save’ sick monarchs, butterflies heavily infested with Oe, or kept in crowded containers or on unhealthy plants.

We urge people who love monarchs to remember they’re wildlife, and not pets. They are cold-blooded and do not ‘suffer’ in the cold. Their wings are waterproof and they can cope with rain. Caterpillars and butterflies know what to do when it’s raining, or windy. They don’t need to be raised indoors or kept warm through the winter. They should be left to do what comes naturally. The fittest will survive and go on to reproduce. It is important that unhealthy butterflies do not reproduce.

Monarchs have been doing just fine without our help for millions of years. While it’s useful to offer some protection against wasps and other predators, the current advice, based on scientific evidence is to raise monarchs in ways that mimic their natural environment. Overcrowded conditions are not seen in nature.

Monarch butterflies, as is everything in Nature, are part of a natural food chain. Not all are destined to become butterflies. Some will feed other species, some will even feed the soil when they die.

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All insects go through a series of changes as they mature (called metamorphosis) unlike mammals, where the young are born as ‘miniature’ adults.

With moths and butterflies, the first stage is the ovum or egg, the second stage the larva (larval stage) or caterpillar, the third stage the pupa (pupal stage) and finally it becomes the imago or adult, usually termed the ‘butterfly’ or ‘moth’.

Moth caterpillars spin a silk cocoon around themselves to enter the pupal stage.

Most butterfly larvae, however, split open and then the inside forms a transparent skin or cuticle. This is called a chrysalis.

Just to complicate things… there is one species of butterfly in Siberia which spins a cocoon. It’s an interesting story, best told by Eric Carle, author of “The Very Hungry Caterpillar”.

Butterflies usually fly during the day and moths generally at night. Butterflies usually put their wings together above their body when at rest, exposing their body, while moths will fold them over each other.

Another difference is that butterflies have clavate or club-like antennae or feelers, but the feelers of moths are feathery (pectinate).

As well, moths tend to have plumper bodies than butterflies, and because moths’ scales tend to be larger they give the appearance of being more dusty.

There are many types of injuries – and sometimes it is time for the butterfly to die. But in bad weather (cold or wet) you can best help a butterfly by putting it on flowers in a sheltered position, or by bringing it indoors.

Pick some flowers with nectar, and put your butterfly on that, and with warmth, shelter and nectar it may recover.

Remember that a monarch lives only 6-8 weeks after it has done what it is here to do – continue the species. Every living thing will die – but hopefully before doing so it will have added to the population.

It is possible to replace a broken wing by gluing on a perfect wing from a dead butterfly. This is labour-intensive and requires practice. Full instructions can be found here.

If you don’t have the time or inclination to do the job well, our suggestion is to pop your injured monarch into a container and put it in the deepfreeze. Its system will shut down and within 24 hours it will not be alive.

A pupa that falls or is dented may well be infected with disease. It may be best to euthanise the pupa (by wrapping it in a tissue, and putting it in the deep-freeze). You certainly don’t want to foster disease or a virus.

If you are sure the chrysalis is not diseased (e.g. you knocked it off yourself) it can be rehung by tying cotton around the cremaster (the black stem at the top) using miniature pegs, or it can be glued by using a glue gun. Place a bead of glue on a suitable support and then place the silk mat or the cremaster into the glue.

Pupae do not need to be hanging for the butterfly to emerge safely. You can leave the pupa next to an upright support and the butterlfy will climb upwards so the wings can hang down as they dry. One suggestion is using a food cover (the umbrella type) and putting the pupa onto a paper towel inside and next to the wall of the food cover.

In NZ the natural food species of the monarch (Danaus plexippus) larvae is the Asclepiadiae family – milkweed which includes swan plant (Gomphocarpus fruticosus) and giant swan plant (G. physocarpus) as well as Asclepias species such as tropical milkweed/bloodflower (A. curassavica). The tropical milkweed comes in two colours -scarlet (which has a gold centre) and gold (all yellow).

The term ‘milkweed’ can be confusing – but a Fact Sheet on this is available. The Moths and Butterflies of NZ Trust will be able to help you with seed of the giant swan plant and tropical milkweed, see our shop.

When caterpillars have eaten all the leaves of your milkweed they will then eat the stems and fruit (seed pods). You can crush the ends of the stems to soften them too while you sort out a long-term solution. Don’t let them wander away!

*** If you have “run out of food” place a notice in the forum but make sure to say where you live. Or try the Facebook page, “Monarch Matchmaker“. Someone in your neighbourhood may be able to help!***

Adult butterflies need plants giving nectar. They usually choose flowers with bright colours, purples, pinks and blues in mass plantings. Buddleias and Hebes are very popular. There are more listed in our forum – click on the link on the homepage to go there. There is a poster showing many nectar plants available from the MBNZT. See it here.

The worst pests are undoubtedly social wasps; ones which take the larvae (caterpillars) and eggs until late summer, when the juvenile wasps’ diet changes from protein to nectar. There are other wasps that parasitise pupae too. Some wasps have been deliberately introduced to control the white butterfly.

Most birds will take one taste of a monarch and find it too bitter, so recognise the warning colours and don’t try to eat it again. The monarchs are poisonous from the cardenolides in the leaves of the milkweed. This doesn’t seem to affect the shining cuckoo, however.

Praying mantises will eat caterpillars, as will the Predatory Shield Bug (Cermatulus nasalis). Ants will also take eggs.

Disease can also be transmitted from caterpillars and will badly infect pupae – so if you are breeding monarchs ensure that you keep their food supply in small, separate ‘islands’ in your garden rather than a concentrated area. In this way, any disease cannot spread as rapidly. If you keep caterpillars in containers try not to have them all in one container, and clean each container with a bleach solution before reusing.

Remember too that every species has predators and parasites which contribute to the circle of life. A monarch will lay 300, 500, possibly a thousand eggs… so not all are destined to become beautiful butterflies.

Consider doing a “Create Butterfly Habitat” course (on-line) to learn more about our butterfly species and how to avoid disease and other pests.

If you have too many caterpillars, move some of them to where there is milkweed with no caterpillars; don’t let your plants get inundated with larvae. Post in the forum where you are and how to contact, and you might find others in your neighbourhood have excess swan plants.

Yes, but it is always better to choose a natural diet, the nectar from fresh flowers. In a country like NZ there should be no need for artificial diets. Also in cold dry weather sugar water can form crystals inside the butterfly. Add a drop of soy sauce to give minerals needed for reproduction.

Do not use honey as it could be spreading bee diseases.

Firstly, remember that a female monarch will lay hundreds of eggs – one laid over a thousand! So not every egg is destined to become a butterfly. Every species in Nature has its predators and parasites, which keep the numbers in balance.

However, that being said there is currently an imbalance of wasps vs butterflies and the wasps are winning. So here are some tips.

You can grow your plants in pots, and move them to where the wasps can’t find the plants or grow them under cover, such as a mosquito net.

You could also purchase a ‘caterpillar castle’ from us – see them here.

Even an old net curtain will help. Throw it over the plant and the monarch will lay eggs where the net touches the leaves. Cover a plant when you have seen a female monarch laying eggs. The eggs will hatch, the tiny caterpillars can crawl through the net and live relatively undisturbed from wasps. You can then watch your caterpillars grow. It’s not 100% foolproof, but is better than letting the wasps have them all.

You can plant swan plants close to other bushes, the branches of which will offer protection to the young caterpillars as the wasps can’t reach the swan plant growing intertwined with branches of the other bush or shrub. Don’t have a swan plant as a “specimen” plant (solitary) as it will not affect much protection for the caterpillars against wasps. Prune your plant so that there are many branches, providing many leaves.

There is more information about wasps and other pests under Species / Pests on our website

and also tons of discussion in the forum, http://www.nzbutterflies.org.nz/forum/tags/wasps

The process from egg to butterfly is weather dependent and also depends on the regional climate. It can take about four weeks in the peak of the summer in warmer climates. The egg takes 5-10 days, the larva/caterpillar and pupa/chrysalis each take about 10-14 days.

In winter, autumn and spring it takes a lot longer (if it happens at all – they can continue to breed throughout the year in Auckland, Bay of Plenty, Nelson-Marlborough and Northland).

The process slows down in cool weather; in this way we can ‘use’ the climatic conditions to speed up or slow down the creation of a butterfly.

When the pupa is ready to hatch, the shell will be transparent and you can see the dark colours of the butterfly’s wings folded up inside. The transformation happens suddenly and if you turn away for a few minutes you will usually come back to find a butterfly.

Males have a black spot on each of their hindwings. These are scent glands. They also have thinner veins (lines) than female monarchs.

Thanks to Dean & Lois Farrow, Christchurch, for permission to use their photograph.

After mating the butterfly has done what it was created for – to continue the species. Males will die 6-8 weeks after using up all their sperm mating with a succession of females. Similarly the female will die after she has laid all her eggs – usually between 300 and 400 although one monarch laid over 1,000 eggs! Only a few of these eggs will mature to become butterflies – some will become food for predators or succumb to parasites etc.

Milkweed (such as swan plant) is easy to grow. Just make sure that your soil is not too fertile or rich. You will see that the strongest plants grow in ‘wild’ gardens.

Most garden centres sell swan plants (a type of milkweed) in the season – but ask at the counter if the plants have been sprayed. Some growers/garden centres spray their plants with insecticides to keep them looking good, and of course this could kill your caterpillars. These plants will be suitable for the next season.

You can also buy seeds from the Trust. Plant them NOW (whatever the time of year) and grow them so you have lots of food for your monarchs in the spring or look for Yates seeds at your nearest retailer.

Seeds are $5 a packet. https://www.monarch.org.nz/items-for-sale/seeds/

Once your plant is well established you can save your own seeds and have plants growing forever. In the meantime, consider doing a “Create Butterfly Habitat” course (on-line) to learn more about our butterfly species and getting the best from your plant.

The process is very simple – grow some milkweed in your garden, and you will soon embark on a wonderful adventure. The female butterfly will donate a few eggs to your cause as it flies around looking for milkweed. The eggs will hatch, and out will come caterpillars – and you’re in business.

When purchasing a swan plant (milkweed), ask the retailer ‘is this plant safe for caterpillars?’. If not, i.e. if it has been sprayed to keep it in pristine condition  leave to grow in a corner of the garden and protect it from the female monarchs so it will be of a good size for the next season. In the meantime, consider doing a “Create Butterfly Habitat” course (on-line) to learn more about our butterfly species and getting the best from your plant.

As issues arise, we will gladly help you with information to help you – post queries in the forum (or search there for answers). Soon you’ll be hooked, as we all are!

Many people are concerned for their monarchs (caterpillars, pupae and adults) when there is a sudden change in the weather or when winter arrives unexpectedly.

The first thing to remember is that monarch butterflies are wild creatures and have been surviving for many years without human intervention. For all sorts of reasons not every one survives – but as each and every female monarch can lay something like 300 or 500 or more eggs not every monarch is meant to survive. Imagine how many monarch butterflies there would be if we helped every one! Some are destined to be food for other animals, or even detritus to add another element to the soil.

The other thing to remember is that monarchs are not built like humans and do not experience the same sensations. Just like other wild animals they adapt to whatever conditions Nature throws at them. They don’t think weather is ‘bad’, ‘stormy’, ‘miserable’ like we do. They can probably sense bad weather coming better than we can. Whereas we shut the windows, turn up the heat or add another layer of clothing wild animals, just as their forebears have done for thousands of years, will more than likely find shelter and wait the weather out.

Butterflies will hold on to their perch and try not to get too wet. They may even move somewhere offering more shelter. Their wings are naturally shower-proof; the rain runs down and off them like it does off roof tiles. When it’s warm and sunny and the last drops of water have evaporated off their body, a monarch will fly about, bask in the sun and look for food (nectar). If it’s winter they won’t breed until the spring.

If you have raised monarchs indoors and the weather is not favourable to put the butterflies outside we suggest you put them somewhere cool and dark so that they are experiencing similar conditions to outside without the wet and wind. That way they will acclimatise more easily. They will not need to feed until the weather changes.