No stereoscope or microscope needed!

healthy, normal abdomen

unhealthy, Oe-infected abdomen

Note the second butterfly; it has a 'normal' abdomen and showed no evidence of Oe. If you compare the two abdomens, you can visually note the difference. It isn't necessary to have any special equipment!

Look at this newly-eclosed male. Note the solid black and misshapen body, the asymmetrical wings, and upon looking at a close-up of the abdomen, the mottled, indistinct white stripes against the black.

mottled abdomen
oe monarch male full shot
oe monarch male

Wrinkled hindwing, white stripes are not clear…this male Monarch is obvious not perfect!

What to do if you suspect Oe

If you do find that you have a caterpillar or pupa or adult Monarch with Oe, the best and only thing you should do is to euthanize. Keep in mind that by permitting the butterfly to live will only perpetuate the disease and allow it to spread to other butterflies. It is a selfish act to release diseased butterflies as it hurts the environment and will only eventually weaken and kill off the Monarch.

Euthanize by your favoured method. Two possible methods: freezing (placing the specimen in a baggy and then placing in the freezer) or using a 'killing jar' (take a jar with a good-sealing lid, placing the specimen inside, and soak a cotton ball with nail polish remover containing acetone and placing it inside the jar).

Be sure to SANITIZE everything that has had any contact with the butterfly. The Oe spores can easily spread and you do not want to chance spreading them around, especially since they are so tiny and are hard to see with the naked eye. Clean everything carefully, wash your hands and use a paper towel so you can throw the paper towel away.

Please be responsible. Think of the environment AND the butterflies!

OE and the Monarch

If you raise Monarchs then you need to become familiar with something called 'Oe.' Oe is the shortened version of Ophryocystis elektroscirrha, a protozoan parasite that infects the Monarch (and Queen butterfly) world-wide. This parasite is a spore that can be found in the cuticles between the scales on the wings and abdomen of an adult butterfly. Using a microscope or stereoscope, some tape, and white paper, it is easily detected, and with care, can be somewhat controlled in your own gardens. *I say somewhat controlled because you can only control what you raise and release! You are not truly able to control the 'wild' butterflies that come into your garden unless you capture and test each one.

Things to look for if

There are certain things you can look for, visually, if you suspect Oe parasitization in your Monarch. Some are easy to SEE with your eyes and others require a microscope or stereoscope.

Larva (caterpillar)

In larvae, check to see if your caterpillars have cleanly marked stripes. If the stripes are mottled or dirty looking, your caterpillar may have been parasitized by Oe. Also check to see if the fleshy filaments are symmetrical; are they the same length? If one is shorter than the other or misshapen, you do not have a healthy caterpillar.

Possible symptoms of Oe parasitization in a Monarch caterpillar:


Pupa (chrysalis)

If you don't notice anything unusual during the larval (caterpillar) stage, then pay close attention during the pupal stage. Normal Monarch pupae are evenly coloured and as they change, you can see the wings developing. Pupae should be a green colour and should show NOT freckles or spots in the green. The gold dots are normal. What you want to watch for are strange brownish-coloured freckles or spots that will appear. These spots will begin appearing within a few days but may take longer. Any odd colours that show up indicate an unhealthy pupa. Period. (Note: Oe parasitization looks different from Tachinid Fly parasitization although spots DO indicate an unhealthy butterfly!)

Possible symptoms of Oe parasitization in a Monarch pupa:


Imago (butterfly)

You don't have to hav a microscope/stereoscope to get a visual on Oe. Athough this visual method is not exact, oftentimes, you can spot Oe-parasitized butterflies. In the first picture note the odd shape of the abdomen and how the spots and stripes are somewhat unclear and not very pronounced. This butterfly showed many Oe spores under a stereoscope.

Possible symptoms of Oe parasitization in a Monarch butterfly:

Remember: Whatever happens during the

2010–2013 Sherry Skipper Spurgeon All Rights Reserved.


Dr. Sonia Altizer and her staff at the University of Georgia have been studying Monarch health and research the effects of Oe. She has launched a Citizen's Science program that is outstanding and can include data from the Monarchs you rear if you sign up! She is one of the leading experts in the field.

Go to Monarch Health for more information.

Oe is a type of parasite that has to live within its host to grow and multiply. When it isn't in the host, it survives as spores that are resistant to environmental conditions and can lay dormant on plants. Dormant spores are also found on the outside of butterfly wings and bodies and are scattered when the butterfly flutters about onto plants. A caterpillar will eat Oe spores that have fallen onto its eggshell or onto a Milkweed leaf and thus, the life of the Oe begins in its host, the unknowing Monarch caterpillar. The caterpillar's digestive enzymes releases the Oe from the spore, thus beginning Oe's reproductive phase, with the majority of damage to the actual butterfly during the pupal stage. Once a butterfly has been infected with Oe, it will not recover. Ever. Note that on this pupa you can see the beginning of the spore begin to show. Yes, those little polka dots are the spores!

Why should you be concerned about this Oe spore? Think of it like this: as humans we are concerned about the spread of disease so we use anti-bacterial wipes and gels to keep our environment as germ-free as possible, sneezing into our elbows and using tissues whenever possible. Our bodies produce antibodies to help ward off the ill effects of the germs. We don't become deformed if we do get ill but if we do get sick, lethargy is usually the case.

With a Monarch, a case of being parasitized by the Oe spore can cause a number of ill effects ranging from low body weight to an inability to eclose (come out of the chrysalis) to improperly formed wings to lack of ability to fly as an adult. The spores can be transmitted genetically so to raise and release butterflies that have been parasitized is not only unwise but also shows an irresponsibility to the environment as it promotes the spread of disease. So, learning about Oe and learning how to detect it and squelching it is important. Period.