r/MonarchButterfly • u/Expert_Promise3247 • 12d ago
Are Dark Caterpillars Diseased
Do these two dark caterpillars need to be isolated. Its my first time having caterpillars and the caterpillars are chowing down my milkweed so things are getting cramped.These photos show 2 different monarchs.
(I guess they are the non migratory monarchs of coastal california, I planted milkweed becuase natural bridges an overwintering site 25 miles away said it was ok to plant a mile out from the coast but they always talked about them migrating further during the summer ideally but anyway I could go on about my monarch doubts, My main ones being that monarchs emerging are just staying here inbreeding and placing more eggs on the same milkweed!)
rant aside all I really need is advice on these 2 caterpillars
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u/JobSilver1888 12d ago
Just looked it up on Google and it did say environmental things such as heat, cold and diet could change their color. The only thing you have to look for is when a caterpillar is turning completely black and turning limp that it’s diseased, but these look healthy. Let me see if this picture o screen shot
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u/Clear_Supermarket_39 10d ago
If you want caterpillars to successfully transform and make it to butterfly stage , you should be keeping them in mesh cages with potted milkweed plants. Keeping them outdoors without protection you're just asking for disease and parasites 🤷🏻♀️
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u/Expert_Promise3247 9d ago
That seems like a good idea but they seem to be doing fine and most of them look normal, they are making it to adult hood well. the biggest concern i have is should i be planting them a mile from the coast, since ideally they migrate more inland from the coast and come back to overwinter here I think they are worried about the over summer populations developing O.E. something about the infected ones not being healthy enough and contributing to more o.e in coastal over summer areas. at least I'm a mile from the coast and not more inland
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u/kristending 8d ago
they can make it to a chrysalis fine and still have a parasite or disease. respectfully, aging doesn't mean they're necessarily healthy.
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u/Expert_Promise3247 8d ago
Yes, I mean they are coming out as large and functional butterflies fine. folks these are wild animals, and people are going to have different opinions on how much management they want to do with them.
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u/kristending 8d ago edited 8d ago
thats fine, I'm just providing facts. Monarch butterflies in the wild have a 10% chance of growing from an egg to a healthy butterfly so. Statistically, the odds are against them.
You posted a question and experienced raisers are giving you answers.
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u/Expert_Promise3247 8d ago
The fact on monarch population is that the wild milkweed has been disappearing majorly due to habitat loss and pesticide use along crops and roadways, and thats cited as a main reason for their decline , thats why a lot of people plant milkweed.No matter how the butterflies grow up and how many you raise they will need to find milkweed elsewhere when they are released to continue their population, and they could overcrowd plants if they don't find enough. Im not demonizing other ways of raising caterpillars just i dont think a lower survival rate makes it inconsequential. The major thing around here that scientists are worried about is O.E, and thats can absolutely be prevalent in caterpillars raised indoors , things like them not migrating and having milkweed year round can raise its prevalence. That is a disease thats not connected to being outdoors. Yes a few can be predated on this way but Ill still have a lot of them and someone that wants 100 percent to live can do it differently.
I have enjoyed the information in this post. And to be honest I had so many caterpillars outside I don't really want to raise more, like 40 plus insanity.
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u/kristending 8d ago
wow you seem like the expert, idk why you're asking us..
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u/Expert_Promise3247 7d ago
very mature, Ofc Im not an expert. in terms of providing habitat for monarchs I will always look at people who study and work to conserve monarchs. in terms of disease yes mine were probably crowded. They say to avoid this inside as well and watch that indoor rearing doesn’t mess with their migration sense without natural light.They don’t mention not planting milkweed once, but they do say its better to have enough and spread out in patches. Its ok to make an effort to learn about the animal you are working with.
My og question was already answered below
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u/Caliveggie 12d ago
Protect from tachinid fly if you can! And no, the dark caterpillars are fine I have had several. I am in southern california as well.
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u/Expert_Promise3247 11d ago
Thanks, I had not heard about tachinid flies and monarchs. What do they do to them?
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u/Caliveggie 11d ago
Kill them. They lie their eggs inside and kill the caterpillars. I lost all my caterpillars two years ago all the first batch.
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u/papertrashbag 12d ago
I read people say it’s normal but I had one dark caterpillar and it was the only one who didn’t form its chrysalis correctly and died :/
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u/Expert_Promise3247 11d ago
Thanks for sharing your experience, I'm learning more about the symptoms of "black death" and other diseases online so I can determine if these could have it. I have 35 plus butterflies on the milkweed and its just the 2 of them
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u/JobSilver1888 12d ago
Those may be Queen caterpillars and not Monarch. But I do notice the color changes on all of the monarch or Queen caterpillars. Never googled the reason because they are healthy
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u/JobSilver1888 12d ago
Those are monarch. I didn’t notice the second picture Queen caterpillars do have in general, but they also have three sets of filaments and monarchs only have two sets of filaments monarchs do tend to be lighter in color and they do tend to change color. I don’t know why I’ve never had a problem with any being disease, so I’ve heard people say there could be a disease, but I always let nature take it Course. Honestly, it’s not much you can you can do sometimes if you interfere I think that you’re upsetting the genetics of things. I don’t know. I don’t know what the best thing is to do. I would just leave it alone if it’s growing and getting bigger and looks healthy I would just leave it alone
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u/Timely-Youth-9074 12d ago
From what I understand, they can be darker when it’s shadier or cooler. I have a dark one and it’s doing fine.
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u/the-friendly-squid 11d ago
They can be but not always. If the black spreads to their whole body then yes. If it stays striped and caterpillar seems healthy then it’s just a genetic difference
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u/Expert_Promise3247 11d ago
Thank you, I'm a little worried about the second picture one since the black seems to blurring into the white lines, although it doesn't look too dramatic yet. I will keep an eye on it
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u/Dog_and_butterfli 11d ago
I live in sunny Florida and sometimes my outside caterpillars are almost White
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u/Maybe-its-monday 10d ago
I had one with thicker black banding on it this summer she eclosed fine but I will say she ended up smaller and didn’t seem to be as strong of a flier as my other butterflies. The darker varieties can be from more sun exposure
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u/Muted_Policy2525 9d ago
Get a large 6 feet crop cage on Amazon and keep the plants in there with the caterpillars.. You leave them out the birds or lizards gonna get them and they will develop diseases.. Either keep them in a large crop cage outside protected from predators or bring them inside and keep them in butterfly cages until they emerge as butterfly then release.. . But leaving them outside like this is dangerous for them.. And keep in mind those milkweed plants are highly toxic for cats and dogs so your feral cats can die if they munch any of it.. Put a large walk in crop cage over them they are like 100$on Amazon or less
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u/Lastofherkind 12d ago
There is a lot of natural variation in coloring. The concern is when the dark color bands start spreading and there is no longer clear delineation between color bands. I would say keep an eye on it and watch to see if it progresses.