Moth emergence

You should be fine I mean if the moths do hatch let’s give a week before they start it would be April two more weeks before the eggs hatch and there should be leaves.
but if you had a problem you could try artificially overwintering them for longer than they would outside

Or do you just keep the pupae too warm?

Actually I think the Pictures you are referring to are not from this year. There are trees with lots of leaves and cateepillars in L5 on mature leaves. So this cannot be from this year from Canada.

I see people post pictures from various dates, sometimes over a year old, emergence is effected by a number of things,
if it's natives you're wondering about, this year will be pretty much like the last. My apple is just budding, the willow has small
leaves, we've seen what was probably the last frost a few days ago.
I've been thrown off by pictures, until I read when the picture was created, I suppose it's a matter of having the time to upload,
not everything is current.

Hi Alessio,

Does it revolve around temperature, development time, or when the foodplants are available?

In generally: Depends on which species you've got. There are species-groups supposedly emerge due to temperature (overwintering species which subsequently follow the availability of foodplants in spring), other according to the development time (2nd generation of the previous group) and some species of tropical and subtropical regions, and a further large group follows the light conditions (extremely in Indian wild silkmoths). At the wild silkmoth (Saturniidae) this group contains genera were the pupa has got a light detecting "window" at its head (e.g. Antheraea). There is a further group not listed by you: This are species hatching after the monsoon commenced, that means when the temperature in hot climates drops down a Little and the pupae became more often wet due to rain / humidity.

Depends on the pupae you've got you need to keep them more cold, more dry or with less day light to prevent them from (too) early hatching of the moths.