In Which Monarch Mothers Medicate

To grow up sick with parasites is bad,
To pass them to one's offspring just seems worse.
But somehow, Monarch butterflies who've had
Ophryocystis bugs just know to nurse
Their caterpillars, in a fashion, by
A-laying their eggs on a milkweed type
That makes cardenolides that help to fight
The protozoans. When those eggs are ripe
And hatch, the larvae get their medicine
With ev'ry meal - and yes, it's proven, too,
That butterflies who simply haven't been
Afflicted don't do what the sick ones do.
We're not the only ones, then, who do drugs.
In this we are no diff'rent from the bugs!