It’s a magical moment in the life of a  monarch butterfly — and a vulnerable one.

Its metamorphosis complete — it  breaks free from its chrysalis   and pumps fluid from its abdomen  into its spectacular new wings.

But for some it’s a struggle.

An old enemy, a parasite called  Ophryocystis elektroscirrha,   known as OE, is making it harder for monarchs  to undergo this crucial transformation.

The infection causes sticky sores on the abdomen,  trapping the butterfly inside its own chrysalis.

And by trying to help monarchs, we  humans might be making it worse.

Each summer, monarchs make their homes in  milkweed patches all over North America.

When infected females lay their eggs on the plant,   they unknowingly drop microscopic OE spores  onto the eggs and surrounding leaves.

A few days later the next generation begins.

The caterpillar goes to work, munching  on the empty shell of its old egg.

Then it’s on to the milkweed.

With each bite, the caterpillar downs more and  more of these microscopic, football-shaped spores.

Inside the caterpillar’s  gut, the spores break open,   releasing wormy-looking parasites that burrow  out of the gut and into the caterpillars flesh.

When the caterpillar transforms into a chrysalis … The parasite starts multiplying  rapidly, stealing nutrients and   taking up space where the monarch  would normally grow skin and scales.

When it’s time to emerge, the weakened  butterfly fights to free itself from   the sticky chrysalis – attracting  predators and exhausting itself.

Some never escape.

Others do, but with wings that are all  crumpled and deformed … never fully extending.

Or just bent and uneven, making it harder to fly.

Researchers at Emory University in Atlanta   take samples of monarch scales to  hunt for OE under the microscope.

See all those tiny black specs wedged  in between the monarch’s scales?

Those are OE spores.

Unfortunately, this one’s infected.

But OE has been around a long time.

So what’s making it such a big problem now?

Well, monarchs have lost much of their summertime  milkweed habitat to agriculture and development.

Every stage of their life cycle is connected  to this family of unassuming plants.

At the end of summer the local milkweed dies  off and the monarchs head south for the winter.

When the plant dies back, it  takes the OE down with it.

That’s good.

But, in an effort to help monarchs, some of  us plant tropical milkweed in our gardens,   with its showy yellow and red flowers.

Tropical milkweed sticks around a lot  later into the year than native milkweeds.

That means more time for OE  to build up on its leaves.

And because the tropical kind doesn’t  die back with the rest of the milkweed,   some monarchs don’t get the  signal to start migrating.

They just hang out on the infested  plants, missing their chance to hook   up with all the other butterflies that  spend their winters partying down south.

What’s worse, they spread OE to healthy  butterflies that pass through on their migration.

So, if you wanna help the  monarchs – do 'em a solid!

Cut back your tropical milkweed in the fall.

And the next time you plant milkweed  ... make sure it’s a native kind.

With all the problems that monarchs face,  this is one small thing we can do to help.