I started raising butterflies in 2018 and that year I had great success, but in the spring of 2019 and 2020 I had terrible success raising the Monarchs.
I had a better place to raise them, I cleaned their cages every day, rinsed off the milkweed before replacing the old milkweed every day, but most of them failed forming a chrysalis.
They all died while forming a chrysalis and green liquid oozed out when I put them on a piece of paper.
Does anyone know what could’ve caused this?
I’m thinking that maybe they were sensitive to the tap water, or tried forming a chrysalis too early?
Any help would be appreciated!
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What is the source of the caterpillars you’re raising? Are you collecting them outside? And are you keeping them in a cage that keeps other insects out, even tiny ones? My first suspicion here would be some sort of parasite. I have seen chrysalises die or caterpillars fail to form a chrysalis when they were infected with tachinid fly larvae. If the chrysalises are oozing liquid from tiny holes, it might also be a braconid wasp problem. I haven’t observed those yet but based on the pictures I can find they are tiny. It looks like you’re using one of those “Kritter Keepers” or whatever they call them, which have lids that would allow those insects to get in. You might want to try pulling pantyhose over the lids to keep them out if that’s the case. If you can rule out parasitoids, the next possible explanation may be some kind of pathogen such as a bacterial or viral infection.
I found all of them outside, some were eggs and others larva, and I put them in different kinds of cages. The one in the picture probably wouldn’t keep out parasites, but the other containers would. I examined them and found no signs of parasites.
I noticed that when the monarchs were forming a chrysalis, they started sliding out of their skins instead of shedding them.
could it be due to a lack of humidity?
btw, that’s a beautiful rescue dog.
Ooooooooh! That might be it! In 2018 I had them in a bathroom that was very humid but I moved them to the living room/mudroom last year and the year before.
And thank you very much! I think she’s a Tamaskan, because her appearance and behavior are very similar to one. She is very very sweet!
Some good suggestions. I think virus can be ruled out if the second picture shows the ooze. Viruses usually turn the larvae into floppy bags of black goo. It may also be a hormonal problem - in the last photo it looks like the lava failed to form a pupa. It looks like it went straight to an adult form (head, possibly thorax). I don’t know where you are, but perhaps the milkweed was sprayed with something that affected the hormonal balance of the insects. My advice would be to follow the simple steps (parasite barriers, moisture) first. Oh, and wash the containers with bleach before starting the next round, just in case it is a disease. Rinse well!
Hopefully a move back to the bathroom will solve things.
I had not hear of a Tamaskan so read a bit about them, beautiful dogs and apparently well-tempered as you indicated yours is.
We live on a 15 acre property, but our neighbors do spray occasionally. It could be possible that the milkweed was poisoned by our neighbor’s spraying, but I think it’s more possible to be from the tap water. I watered my Orchids once with tap water and almost killed them.
I don’t think it’s NVP, because the caterpillars never turned black…
Yea, most of those were me just thinking out loud. Thoroughly cleaning the containers, a move back to the bathroom and ‘parasite proofing’ are easy ways to start.
Is your tap water safe for you? Do you filter before use?
Yes ma’am, we filter our drinking water. I know there’s no lead or anything like that in it, but I do know there are things like chloride in the tap water.
I used tap water to rinse the milkweed, and to water my Orchids once.
As someone who’s done a lot of lepidopteran rearing for research over the years- this looks like a pathogen of some sort, likely viral.
Wash/soak all your cages/nets/anythings these bugs have touched in Bleach before rearing another generation.
The hormone observation is interesting. Are you using news paper or papertowels in the enclosures? could be JH.
JH was discovered by examining differences in rearing/survivability when they changed brands of paper during a rearing project.
I’ve never heard of JH before, but that’s interesting how it was discovered!
In some of the enclosures I used paper towels and in others I used nothing. (The bottom of the cages were plastic.)
Very interesting. I had not heard about that. Thanks for the info!
I really wanted to try raising butterflies again, so I went and found two monarchs. One of them is (i think?) only 4th instar and it’s trying to form a chrysalis! (Photo from observation.)
Lol, nevermind. It was succesful! This time I didn’t rinse off the milkweed and I put it in the bathroom. Sorry for the blurry picture.