OE in Danainae

ladobeSeptember 25, 2011

Should I, or shouldn't I? With so many folks here that can't seem to handle doing what has to be done, I've always been reluctent to respond to discussions about OE in those species infected by it (plexippus, gilippus, etc). Maybe its time since it is coming up again in multiple threads, and remaining quiet does more harm than good.

At least most of you folks in the east don't have to deal with it as often or as seriously as the rest of us do, thanks in part to your large land mass and shear numbers present in the east. OE is at least three times worse in the west, and maybe 10 times worse in the non migratory colonies, like in HI and along our extreme southern borders (and south of some of them).

It surprises me though how many of you try to allow OE parasitized livestock go through their complete metamorphosis, and set emerged adults free that are infected but survived to that stage. Both practices simply spread the infestation throughout the colony. Much better for the colony would be to destroy any livestock (and any around them) that are even suspected of having OE when the earliest signs of it show up in the lava, pupa or adults. That means the entire brood and anything associated with them. Loosing the few you are rearing and the plants in your gardens they were found on is far better than helping OE spread by not destroying all of them, and sterilizing any equipment used for them. Instead of helping the species as you are trying to do, you are in fact hurting it AND actually killing far more individuals then those you were rearing. Every future generation from infected adults will most likely also be infected. Fortunately OE infected adults are weaker, don't fly as far or live as long, and some may not even mate... its those that do that keeps OE going strong.

While there are other ways to detect OE early even without a lab, some easy clues for the layman might help. OE is not easy to detect in ovum just by inspection, although if laid by an infected female they might contain the protozoa, and will certainly have dormant OE spores present on the egg and the surrounding host plant. A newly emerged larva will assure it's infection when it eats its egg capsule and the surround host plant. And the infected larva will pass the infection to other larva present via its frasse and any reguritated fluids. Larva that are listless, take longer than normal to complete instar stages, are stunted, not robust and plump, discolored in patches or have trouble pupating are all early signs that OE may be present. Discolored, even if only in small spots, lack of plumness and failure to respond to touch are indicators of OE in pupa long before they turn into a black, smelly mess (same as with larva). In adults, many with OE will never escape their pupal case or fully spread, some that do form will have shorter or unproportional forewings than normal, some will be discolored and all will be weak and short lived.

It's a personal thing I guess, but IMO any livestock in question with even the slightest doubt should be destroyed immediately whether its OE, some other parasite or a viral or bacterial infection. And those suspected of having the later two should be treated the same as OE with the entire brood destroyed.

Some will do the right thing, some will not, so all just FWIW. I learned long ago not to take chances with suspect livestock as more could always be obtained later. But only you can decide what course to take with your livestock.


Thank you for reporting this comment. Undo
butterflymomok(7a NE OK)

Thanks! It's hard to destroy larvae, pupae or butterflies, but it's the responsible thing to do.


    Bookmark   September 25, 2011 at 6:47PM
Thank you for reporting this comment. Undo

Thank you for this post. I am in the process of doing exactly this and it sickens me. Your post gives me the encouragement I need to destroy the larvae.


    Bookmark   September 27, 2011 at 10:31AM
Thank you for reporting this comment. Undo

I cut the milkweed down to the ground, will this be sufficient?

Thank you

    Bookmark   September 27, 2011 at 11:08AM
Thank you for reporting this comment. Undo

"I cut the milkweed down to the ground, will this be sufficient?"

Hard to say for sure, but it is a steep in the right direction.

When an OE infected female lays her eggs, the spores on her get on the eggs, the plant and some maybe on the soil. The spores are quite resilient and can lay dormant for a long time waiting for a new host to happen by and make contact, whether it be an adult or larva (or third party for that matter). It's about the same with the larval fluids, although in this stage most of the OE would probably be protozoa (but also some would be spores). In the pupal stage massive quantities of spores are produced, so the eclosion also scatters a lot of spores around. I have no idea how long specifically for OE spores, but I do know some spores/ovum can remain viable for centuries.

How far you go only you can decide, but you will never completly eliminate it in your garden once it's there. Anyplace an infected adult visits will have spore transfered to it, not just the larval and nectar plants. Same with the larvae. Fortunately the number of infected adults that will visit your yard any gioven year will be low normally, and in time the spores will be consumed by something or work their way deep into the soil.

In my case I left nothing to doubt with OE (or other parasitoid, viral and bacterial infections), and discarded or steriziled everything. With that I at least reduced the chance for possible reinfections as much as I could within reason.

    Bookmark   September 27, 2011 at 1:55PM
Thank you for reporting this comment. Undo

"Your post gives me the encouragement I need to destroy the larvae."

Just focus on the fact that they will soon die anyway, and by destroying them you are doing the responsible thing for the species as a whole by helping limit the spread of OE to your colony.

Even here in the west where up to one third of the colony can have OE some years, I didn't see it present at all for years and years on end. Even without a lab there are telltale signs that indicate the presence of OE in all but the ovum stage, so any livestock I even suspected to have OE got destroyed. And that included those I netted out in the wilds. As a lep enthusiast you can either be part of the solution by taking responsibility, or the problem by not doing so.

    Bookmark   September 27, 2011 at 2:18PM
Thank you for reporting this comment. Undo
terrene(5b MA)

Great info, thank you, Ladobe!

From what I've read and your comments confirm this, the eastern migratory population has the lowest infection rate of OE. Nevertheless, I worried about whether any of the Monarchs I've reared have OE, so this year I took samples from the abdomens of 6 butterflies over several weeks. The video at the link below has good instructions on taking samples and I roughly tried to follow this.

I used clear tape and taped it to index cards with info. I don't have a microscope (yet) but my son can take them to his lab at school and take a look (he is a biotech student). The last 3 samples were from butterflies with chrysalises that had black markings that appeared 2-3 days before eclosing. Despite the marks they emerged and flew strongly and appeared to have clean abdomens. If any of them do turn out to have OE, I will take more care next year and don't have too much problem euthanizing when necessary.

Here is a link that might be useful: Video - LiveMonarch - OE identification and Microscope

    Bookmark   September 29, 2011 at 10:46AM
Thank you for reporting this comment. Undo

THANK GOODNESS! ladobe, I am so thankful you have spoken! Seriously, there are SO many idiots out there who are releasing infected butterflies. Yes, I say idiots because, frankly, I am sick and tired of people who will say/write, "I don't want to kill a Monarch just because it isn't perfect" or "I think it is better to let nature run its course" or even better, "I just let the butterfly go and let something eat it." Let me tell you, despite the multitude of emails I receive from folks asking me repeatedly what to do when they find that their Monarch butterfly can't properly eclose from its chrysalis or has bent wings or the other endless signs of Oe parasitization. Seriously. There is also a moron who is posting on several groups spouting that it is perfectly acceptable for butterflies that exhibit the 'symptoms' of Oe parasitization to be released into the environment with no repercussions. Really? ARGH! I am appalled, to say the very least. I cannot believe that scientists can explain the REASONS why it is NOT acceptable to release specimens that are unhealthy into the environment yet people feel that it is okay to do so.

Sorry to go on and on but obviously this hits a nerve with me. As a teacher, I have tried to work with my own students on the importance of being responsible in all manners and in particular, when it comes to our environment. We are ruining the habitat of these beautiful creatures and we need to have pollinators in our world. Allowing sickness to permeate doesn't help, especially if it can be prevented.

Whew! Got THAT off my chest!

As I have included on EVERY one of my Monarch sites, you can easily view Oe-related problems in caterpillars AND pupae with the naked eye. I sent my information on to the scientists at the University of Georgia as well as the University of Minnesota once I began to recognize it myself. A picture tells it all and ladobe is right. It isn't that difficult at all; I've taught Kindergartners to do it! So, be responsible hobbyists and euthanize your sick Monarchs, please.

    Bookmark   September 29, 2011 at 11:31PM
Thank you for reporting this comment. Undo

Good to hear from you CalaSherry, its been quite a while since we met up on the forum. My favorite idiot (to use your terminology) is the folks who will readily and inhumanely kill a garden pest, but can't bring themselves to humanely destroy an infected, parasitized or misformed lep.

Attitudes about lepidoptera certainly do vary widely. It's often those who "think" they care about them the most here, or the uninformed that are usually the most unwilling to do what has to be done for the good of the species. Far too many folks here consider them as pets instead of what they actually are. Cute, cuddly caterpillars and butterflies might slide by OK at an afternoon tea or bridge party, but they don't belong in a naturalists vocabulary. Most here seem to garden for lepidoptera because they want to help the species as well as enjoy their presence, which makes them a budding naturalists of sorts. But a naturalists takes the responsibility right from the start AND gives them priority to do what has to be done for the good of a species, period.

Unfortunately people in general are pretty lazy these days and only do what they have to in order to get by in almost everything. But that's not making the commitment or taking responsibility, and in the case of lepidoptera can certainly invite disease or infection. Raising lepidoptera "the right way" requires giving them priority, and can be very time and labor intensive. So if you are not willing to do both to do it right to help a species, then please don't do the crime by raising lepidoptera at all. Raising substandard lepidoptera WILL effect their species as a whole. They would be much better off fending for themselves than being reared by a person who only does them when it fits in their schedule and part way.

As CalSherry said (and I said before), some OE "indicators" are visable to the naked eye in all stages but ovum. but they are not 100% proof positive of OE. IOW they could be from other parasites, viral or bacterial infections as well. Takes a 60X microscope or loupe, usually dissection, and knowing where to look to be absolutely sure with OE.


    Bookmark   October 2, 2011 at 7:52PM
Thank you for reporting this comment. Undo
Ament(5a SD)

I am glad you posted this information. It's information I did not know and am very grateful to learn! As I am really looking forward to my garden providing for many butterflies next season and future seasons to come! I surely will be keeping my eyes open for this issue and WILL take care of them properly as to prevent any I catch from being released into the population with this problem. :( I have lots of milkweed planted for next year and years to come.

Thank you for the knowledge!


    Bookmark   October 3, 2011 at 1:39PM
Thank you for reporting this comment. Undo

I'm going to add some comments here that I made on another thread to maybe clarify some of my opinions on OE.

As always my thoughts are my opinions based on many years of actually doing, not just accepting what others say. So they are only FWIW to be taken as a person chooses to take them.

IMO common logic dictates that like with most infestation, disease or infection, the level they intrude an individual at can vary widely from minor to massive. That is commonly proved out with OE in Danaidae. If a larvae makes it through complete metamorphosis to an imago that can eclose and form OK, even if OE is present it was a relatively minor infestation in that individual. The opposite being if a larva at any instar, pupa or adult that has OE dies without getting through complete metamorphosis, that individual was obviously infested at a much higher level. Unfortuanately no matter at what level (with OE especially), failure to destroy any sick livestock whether it be OE, another parasatoid, viral or bacterial infection in most cases will promote the spread of any of any of them to other individuals. OE is the prominent one that will carry on to generation after generation beyond a given brood, and nothing but complete elimination of any brood within your control that might be infected with it will help slow it down in a colony. Why in my opinion when it comes to livestock even suspected of possibly having OE it's not worth taking any chances with them "for the good of the species as a whole". For those of use who did/do field work with Lepidoptera, that includes wild Danaidae livestock found or adults netted that show any possibilty of hosting OE.

NOTE: Even if you have a very strictly controlled gardening and rearing rigime (which I doubt any of you have), you won't eliminate all of any OE present. So don't go slap happy destroying everything in sight. Instead be analytical and logical, and then decide what is reasonable for your own circumstances.

Yes, livestock can have OE and not show any of the so called "visible" signs of it, which IMO are not proof positive of OE anyway and can be from other causes. In part why on my OE thread I offered some habit and condition factors that could also suggest OE is present as well even though they also do not prove OE and can also be from other causes. Bottom line, to prove OE is NOT present in an individual for certain takes a microscope or loupe. And in almost all cases if a larvae it will have to be euthanized to test with any certainty. A possibility to check for OE in pupa is to test the purge of the last instar larva for OE, but unforunately that is not 100%.

I'm a lot more scientific in my appraoch to Lepidoptera than all of the folks here, so I don't accept things at face value. I am also skeptical of data from other sources that are not proven to me. The Internet and publications commonly breed misinformation about everything, including Lepidoptera, that is passed on by ACE's who probably got it from another one. So it's prudent not to trust every thing you read on the Internet or in books if it's not from a source you trust.


    Bookmark   October 5, 2011 at 5:17PM
Thank you for reporting this comment. Undo
KC Clark - Zone 2012-6a OH

Since OE is a current topic ... bump.

    Bookmark   June 23, 2012 at 1:44PM
Thank you for reporting this comment. Undo
napapen(ca 15)

do you think it is the same condition in PVS? About 1/3 of my first group have had the failure to slip off the skin at all stages.

I have collected several sets of eggs and babies in the last few days and put them in separate containers rather than as one big family. The containers I use have been cleaned in bleach and washed well.

I did the deed this am to a PVS which came out with twisted wings. I understand why people have problems doing them in. I have 5 weeks into rearing them and feel badly for their problem.

No monarchs yet but the milkweed is beautiful this year.


    Bookmark   June 23, 2012 at 3:08PM
Sign Up to comment
More Discussions
"showy milkweed" asclepias-speciosa plants available
For your information: Milkweed plants currently available...
Ordered seeds.
I ordered some seeds today and was wondering how I...
Jacob BergZone4b-5aMN
Lemon Mint Monarda - Annual, Perennial? Reseeds?
I feel like this question could be posted in 5 different...
Michaela .:. thegarden@902 .:. (Zone 5b - Iowa)
Protecting cats outside
I'm not really into bringing the cats inside, so I'm...
In another thread ladobe wrote: >Sleeving in the...
People viewed this after searching for:
© 2015 Houzz Inc. Houzz® The new way to design your home™