random chance or Murphy's Law?

[kevinkk]

Today I checked the Hyalophora euryalus caterpillars I have sleeved on a Ceanothus bush. 2 expired since the last check a few days ago,
not all that big of a deal.
What is a big deal, are the 2 larva that have started spinning cocoons, in two separate sleeves, a single larva has effectively taken each
sleeve out of commission for the next week or more by spinning directly on the zipper. Now, the zippers are facing up, and that may
have been a factor in choice of location, and Ceanothus is a "busy" bush, and one I don't typically use because of the difficulty in sliding
sleeves over the branches,but this particular bush is in a micro-climate which is warmer than the sleeve I have on the cherry tree, and the
larva on the ceanothus are in fact growing quicker.
So- I presume the larva put some "thought" into choosing a location for the cocoon, but really?

[mothman55]

I have had the same experience a number of times with Papilio, I rear them in a pop up cage (cut food in bottles) with zippers at the top and all too often they choose the zipper to pupate, I assume because the fabric along the zipper is easy to attach to. Just reared Papilio canadensis and Battus philenor, and about 30% of each chose the zipper to pupate. Has happened in the past as well.

[bobw]

That's what they do! Give them any opportunity to make your life difficult, and they'll take it.

I find it interesting that you call it Murphy's law. Here in England, we call it sod's law.

[kevinkk]

One of the mysteries of life. What will be interesting eventually, is the difference, if any, in size of the adult moths, respectively reared on
Ceanothus, which is one of the foods in the wild, as opposed to cherry, which is less likely to be used in the wild. In other years, I have used the cherry
to raise the euryalus we get from wild females, and those adults are typically a bit larger than the original females, which I always keep for series. It's going to take close to a year, but stay tuned.

[kevinkk]

I have already noticed something interesting about the brood of Hyalophora euryalus. The larva on my ceanothus bush have finished spinning up,
which I assumed they would, because of the warmer and more protected area that plant is in, as opposed to the cherry tree.
Anyway- the death count is 4 larva on the ceanothus, and 0 for the cherry tree, with only the footprint of the house separating the two. I think that's
interesting, now, I don't have any other data to compare, having never used different foodplants for the same species in any year.
Has anyone ever experienced a difference in loss rate for larva in a similar situation? Meaning, is one food plant more likely to be prone to
larval disease than another in the same environment.