What is the OE parasite?
OE is a debilitating protozoan parasite that infects monarch butterflies, with spores deposited by infected adults onto milkweed leaves. Caterpillars ingest these spores while feeding, leading to severe, often fatal, infections that cause deformed wings and reduced survival.
OE must live within a host to grow and multiply. However, when it is not inside a host, OE survives in the environment as spores, which are resistant to extreme conditions.
Life Cycle & Transmission of OE
OE depends upon the host to survive. Only a caterpillar can ‘get’ OE. It eats a spore that was left on milkweed leaves or an eggshell by an adult butterfly. Once it eats the spore, it breaks open in the caterpillar's gut. Inside the spore are OE sporozoites. They move to the hypoderm (just under the skin/cuticle) and begin to duplicate.
At this stage, it is not contagious to other caterpillars. The sporozoites continue to reproduce and multiply inside the caterpillar. This means that the earlier the caterpillar eats a spore and the more spores it eats, the more sporozoites will be in the caterpillar. Sporozoites are the living active OE organisms. They do the damage that weaken and, in extreme cases, can kill the butterfly.
When the caterpillar pupates, the sporozoites continue to reproduce and multiply. Three days before the adult butterfly will emerge, the sporozoites begin to form spores in the chrysalis. Spores are simply a hard casing containing sporozoites. When a caterpillar eats a spore, the casing dissolves and the sporozoites are released.
Before the adult emerges, all OE sporozoites in the chrysalis/butterfly have moved to this layer, just underneath the skin, and have made spores. When spores are made, they are made just below the skin/cuticle. Stop and think about this. The body, other than the area just under the skin/cuticle, is free of OE sporozoites. Spores are formed just under the skin/cuticle.
What to do to limit the spread of OE:
Irrespective of the milkweed you have make sure the leaves are not there past a season. Make sure to prune the tropical, hairy ball and any other milkweed that has leaves at the end of October. Most native milkweeds start dying back around that time. With the climate change the native milkweed is also starting to stay around longer. We can do our part by making sure any milkweed we have at the end of October to either prune or defoliate. This should be done atleast once or twice in a year. this helps the milkweed stay with minimum OE spores.
If we all provide fresh milkweed or leaves that are OE free we can support monarch much better.
Project Monarch Health is a Citizen Science project in which volunteers sample monarch butterflies to help track the spread of a protozoan parasite (O.E.) across North America. This parasite can effect the development of the wings, among other things.
Their mission is to understand host-parasite interactions in monarchs and to enhance awareness of monarch biology and conservation through the coupling of citizens and scientists.
FREE Oe Sampling Kits are available throughout the year, every year.
Send an email to monarchhealth@gmail.com with your mailing address to request one.
Check their new data sheet and the instructional videos on their website to help you fill it out.
Goto: https://www.monarchparasites.org and select the Monitoring tab to view.
We encourage all of you to do this, it is VERY EASY!! And it is FREE!!