Much remains unknown, of course - over generations, it's still
possible that the introduced insects could develop a taste for
native species, or set off unforeseen, and effectively
irreversible, cascades of consequences. Post-release studies of
biocontrol insects are often spotty and inconsistent, adding to
the uncertainty. But so far, these modern biocontrols have shown
few, if any, side effects. In many efforts, the problem is not
over-enthusiasm but underperformance: The insects simply die
out, leaving the job undone. Biocontrol, however, has an older,
uglier ancestry. In the late 1800s and early 1900s, humans
transplanted cane toads, mongoose and other species to new
countries, naively expecting the newcomers to control domestic
pests. People - and native wildlife - are still dealing with the
consequences, and the most spectacular screwups have become
cautionary tales. "When people were doing things like
introducing cane toads, people were making idiotic introductions
all over the world," Hufbauer points