larvae on drugs??!

[Liz Day]

(From Doug Yanega's reprint on releasing butterflies):

> >     Altizer responds by saying that most breeders raise their
> >caterpillars on drugs that suppress diseases but do not actually
> >eliminate them.  

Huh?  I suppose these drugs are antibiotics?  Can someone fill in details?
Is this true?  It's sort of disturbing to think that even caterpillars
have to be given these things the same way cows and chickens do.  (At $10
a pop, you'd think monarchs could "just say no"...)

Liz Day   
LDAY at iquest.net 
Indianapolis, Indiana, central USA - 40 N latitude, zone 5b.
www.iquest.net/~lday