Page 31 - The Book of Caterpillars: A Life-Size Guide to Six Hundred Species From Around the World

LEFT A “good” pest,
the caterpillar
of the Cactus
Moth (Cactoblastis
cactorum) was first
introduced into
Australia to control
prickly pear cacti
(Opuntia spp.) and
later used similarly
in other places,
including South Africa
and the Caribbean.
Now, the rapid spread
of the moth species
in the United States
is said to threaten
cactus industries and 29
the survival of animals
that feed on cactus.
In North America, the Banded Woolly Bear caterpillar (Pyrrharctia

isabella) is sometimes credited with the ability to forecast weather. While
the larva is naturally black at each end and copper gold in between, the
extent of black banding seems to vary annually. More extensive black
banding is said to predict a harsher winter. The population size of another
woolly bear, the caterpillar of the Ranchman’s Tiger Moth (Platyprepia
virginalis), is held by some to indicate the outcome of US presidential

elections. When the caterpillars are common in California, it is said,
a Democrat is voted president, when uncommon, a Republican wins.
Despite an avalanche of opinion polls to the contrary, the Ranchman’s
Tiger Moth caterpillar accurately predicted Donald Trump’s win in 2016.

CATERPILLARS AS PESTS
Mention “caterpillar” to a gardener, forester, or farmer and the response
is likely to be negative. Hungry caterpillars of a small number of widespread
pest species can have a huge impact on humans by feeding on agricultural

crops, stored products, forest trees, and garden plants. Caterpillars of the
Case-bearing Clothes Moth (Tinea pellionella) are notorious for munching
holes in household materials. Millions of dollars continue to be spent on
pesticides annually to control pest caterpillar species throughout the world.

Yet most species do no damage to the things we grow and cherish, and
some have even been employed to kill unwanted plants. The Cactus Moth
(Cactoblastis cactorum), for instance, was introduced into Australia from
South America in 1925, so that its caterpillars could control invasive prickly
pear cacti (Opuntia spp.), which they did with spectacular success.