“Ophryocystis elektroscirrha (OE) is a debilitating protozoan parasite that infects monarchs. Infected adult monarchs harbor thousands or millions of microscopic OE spores on the outside of their bodies. When dormant spores are scattered onto eggs or milkweed leaves by infected adults, monarch larvae consume the spores, and these parasites then replicate inside the larvae and pupae. Monarchs with severe OE infections can fail to emerge successfully from their pupal stage, either because they become stuck or they are too weak
to fully expand their wings. Monarchs with mild OE infections can appear normal but live shorter lives and cannot fly was well as healthy monarchs.
Although recent research shows that tropical milkweed can lower OE replication within infected monarchs (due to high levels of cardenolide toxins), this might not benefit the monarch population. In
fact, this could actually promote disease spread by allowing moderately infected
I PROJECT MONARCH
HEALTH
monarchs that otherwise would have died quickly following eclosion to live longer and spread more parasite spores.“- monarch parasites.