OE – Ophryocystis elektroscirrha? Sadly, yes.
Oh-oh! A Monarch or Queen butterfly chrysalis begins to turn dark in an odd way … wings aren’t showing first … dark patches appear under the cuticle … what is wrong?
The day before a Monarch or Queen butterfly emerges, you will normally see its wings through the chrysalis cuticle. That Monarch orange and black is unmistakable!
Not only do you see the wings showing through the cuticle, the color of the wings (and eventually body) are symmetrical. What you see on one side of the chrysalis is perfectly matched on the other side. Left side and right side matures at the same time and same rate.
But sometimes a chrysalis will begin to show black, through the cuticle, even two or three days before it emerges. The black spots are patchy, not symmetrical. Yes, those dark spots are maturing OE spores.
Bright black marks on the outside of a chrysalis are not caused by OE. Their green hemolymph (blood) dries to black scabs. If a chrysalis has bled a little bit or has been damaged even a small amount, the dried blood can cause bright black marks and spots.
The black of OE in a chrysalis is under the cuticle. It is a muted black color.
If the butterfly caterpillar has had so heavy of an OE parasite load that it kills it in chrysalis, the chrysalis will often begin to turn brown. The brown is often noticed first at the ‘saddle’ or at the ‘cap’ (by the cremaster) of the chrysalis. Brown, in most cases, indicates death.
These photos are of Monarch chrysalises with heavy OE spore loads inside the chrysalises. It cannot spread OE spores until the adult butterfly emerges. Once you are comfortable with your ability to correctly diagnose an OE infected chrysalis, you can limit the number of spores in your emerging area. Most of us will euthanize heavily infected OE Monarch and Queen butterflies. By euthanizing them before they emerge, their spores will never be released into your home, lab, or the environment.
To look for OE when you look at a chrysalis, look at the back side of the chrysalis. The bottom side shows the wings, legs, proboscis, and antennae. Heavy OE will show clearly on the back of the chrysalis, underneath the cuticle, as muted black spots.
Many enthusiasts euthanize infected (or diseased) butterflies (egg through adult) by placing them in a plastic bag in a freezer. Freezing is a quick death for Monarch and Queen butterflies in any life stage.
If you suspect that the egg, caterpillar, or chrysalis is infected with parasitoids (such as trichogramma wasps or chalcid wasps), we recommend leaving the eggs or chrysalises in the freezer for a week and that the bag stays sealed to prevent the wasps’ escape if they do live through a week in your freezer.