Monarch Larvae Monitoring Project


Elaine Witbeck recording the larva count on tropical milkweed.

Volunteer Citizen Scientists are at the field weekly to inspect milkweed plants for the presence of eggs and larvae. This Monarch Larvae Monitoring Project (MLMP) was developed by researchers at the University of Minnesota to collect long-term data on monarch larval populations and milkweed habitat. Some of the enthusiastic volunteers at the Sparrow Field have adopted a species of milkweed or a particular patch where they count the number of eggs and caterpillars on each plant. On the data sheet they record the number of the developmental stages present on an individual plant.  Each stage, which is known as an “instar,” represents the phase between two periods of molting. There are 5 instars for the monarch caterpillar leading up to the formation of the pupa or chrysalis in which the transformation into the adult butterfly occurs.

monarch instars - 3Volunteers learn to distinguish the instars by looking at banding pattern, the head capsule size and the length of the tentacles. The size of the caterpillar alone is not an accurate measure of its stage because individual monarchs vary in size just as humans do.






Larva counts for this year and last year are:

201616771051281098117162277Click here to view all 2016 stats
20152632149334294345494204268Click here to view all 2015 stats


For more information about this project go to

If you would like to participate in the count, join our work party on Friday mornings at 9.




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