ButterflyLady29 wrote:I haven't raised my own the past few years because work interfered and I've seen my visitor numbers dwindle down to near zero this year. Is it the weather? Is it the number of predators? Is it overwintering habitat loss? I wish I had the answers.
I intend to raise more if I find the eggs or larvae. Last year I bought one of those mesh tube butterfly habitat houses. I just haven't had the time to check my milkweed plants.
When we started several years ago, every year, the number of Monarchs returning to our garden and eggs and caterpillars we found increased exponentially. I don't know what makes them come back here -- I don't know if the answers have been discovered. But, each year, we released roughly double the numbers from previous year. ... until the disaster at the wintering grounds in Mexico.
"MY group" probably divides into two groups -- ones that head west and follow the inland corridor to the Texas funnel, and ones that fly the coastal route, flying down to Cape May and over the Delaware Bay, on down to Florida, then split again into subgroups that fly along the Gulf coast to Texas and some that winter in Florida (and maybe some that actually fly across the Gulf Of Mexico).
My layperson thinking is that the population that instinctively returned to our garden was one of the severely affected casualties -- It would make sense that they wintered in close approximation to each other. And it has taken this long for the survivors to increase in numbers again.
SO, I think you will have more visitors returning if you resume raising and releasing them again.
And meanwhile I keep looking at the research. This article from Discover brings up some of the concerns about even small numbers of caterpillars reared in captivity.
https://blogs.discovermagazine.com/crux/ ... -to-death/
They talk about temperatures, lighting, and milkweed quality preventing the caterpillars from getting their environmental cues to prepare to migrate and delay their life cycle.
I have considered building a Monarch house. It would consist of some sort of framework with fabric netting or screen over the frame which could be set over a potted milkweed plant. If the "roof" is also the same sort of screen material then the caterpillars would have the exposure to the natural temperatures and lighting. The main difference is that the caterpillars would be protected from young birds and hungry wasps. It would have to have a door or a flap for easy watering of the plants and to release the mature butterflies. Also it would have to allow for close monitoring of the population.
We have a 2-person pop up mesh tent and also have used a pop up beach cabana when we had so many to release at once and were releasing them with children. This allowed them to enter the "butterfly tent" and for a time, feed the butterflies with pre-flight ration of nectaring flowers they picked as well as cotton swabs dipped in melon flavored Gatorade that was the recommended supplemental food.
I have extra large pop-up laundry hampers as well as smaller hampers and a couple of those zip-top butterfly raising cages. But if you are handy and good seamstress, I'm sure you could build customized protective enclosures that fit your needs perfectly.
I'm not sure I entirely agree about environmental skewing of their instincts since here at least, there have always been wild stragglers that migrate through or eclosed in the garden close to first frost. Once cooler weather arrive with early fall, ones that are raised and eclose in the house stay warmer than the outside night temps which would slow their development down -- I don't believe they mature faster in cooler temps.
...Light quality -- I suppose it could be different if they are bring raised in an enclosed space with no natural light -- I always set them up by the southeast window where they get filtered sun. Most of the later fall ones have been huge migration-ready specimens.
...milkweed quality... Hm. I haven't run out of my own supply since the first year. I intentionally feed them yellowed common milkweed as well as fresher ones from protected microclimates, and other milkweed leaves including honeyvine which remain greenest and freshest until frost.