Monarch Larva Monitoring Project
The Monarch Larval Monitoring Project was developed by researchers at the University of Minnesota. It includes collecting data not just on the monarch larva (i.e. the caterpillars) but also on milkweed habitat.
The goal is to better understand how and why monarch populations vary in time and space, with a focus on monarch distribution and abundance during the breeding season in North America.
Volunteers conduct weekly monarch and milkweed surveys, measuring the density of monarch eggs and larvae and milkweed quality. There are different levels of participation. For example, you can just count monarchs, or you can also note rainfall and/or parasitism and/or aphids. You can do this project either in your own backyard or in another location that has milkweed.
So far, I haven't participated in the formal data collection. I've instead submitted my anecdotal results only from monarchs I raise inside, from eggs and caterpillars collected from my own yard. I suspect, though, that this casual approach is not very useful from their perspective.
Project Monarch Health
In 2015, I participated in Project Monarch Health. I got a report back that none of the samples I had taken from three monarchs had any evidence of Oe parasite spores!