The Iola register. [volume] (Iola, Allen County, Kansas) 1875-1902, 1882-09-01
The Plague Of Caterpillars.

Since the number of individuals, on
the average, remains the same, an enor-
nous majority (say, ninety-nine hun
dredths) die without continuing their
species. Every insect has four stages to
pass through in year, sometimes in half
year or less,-viz., egg, caterpillar, pupa,
and wingedinsect; it is in the caterpillar
stage that all the eating is done. The
caterpillar and the winged state, being
the stages of exposure, are those in which
most of the thinning takes place; and the
latter is the more important stage in this
respect, because by the time caterpillar
has grown large enough to be made a
satisfactory meal of, it has already done
much mischief In the caterpillar stage,
the thinning effected by birds, tree-bugs,
carnivorous caterpillars, ETC., is enOr-
nous. Ichneumon flies are not to be in
cluded, for though they kill, death does
not take place till the caterpillar is full
fed; and, in the meantime, the young,
parasitic family they provide it with has
probably increased the caterpillar's
vOracity. In the winged stage, also,
immense numbers are destroyed by
birds and by bats, and by carnivorous in
sects. But none of these checks on
multiplication, nor all together appear to
be sufficiently variable to account for
that sudden increase in caterpillars in
some years that is spoken of as plague;
the question arises whether we do not
find such check in the weather. doubt
whether anyone who has been practical
entomologist has an adequate conception
of the thinning effect exercised by I'M
favorable weather on insects in the winged
state, or the correspondingly quickening
effect of weather that is favorable. The
effect is concentrated, because the eXis-
tence of insects in this state is brief-a
few days for an individual, few weeks
for whole species,-and it is strong,
because in this stage they are so sensitive
to it. 1t is not merely that rough
weather destroys them, and that in windy
weather they do not fl y, but the mere
absence of sunshine is enough to prevent
many species from moving at all. Like
the "pale primrose" but in different
sense, they
Die unmarried, ere they can behold
Bright Ph9bus in his strength.
The sunless summer of 1860 nearly
eXterminated from some of the Sussex and
Hampshire woods several species which
had formerly been plentiful there. A
rainy fortnight may produce such an
effect on species; on the other hand,
hot fortnight at the right time may foster
an immense increase in the number of
fertile eggs. Even when the speciesdoes
not require sunshine, greater or less
warmth makes vast difference in the
numbers on the wing. I'm hot weather
the slightest touch of the beating-stick
brings them out in swarms, while in or
binary weather they are difficult to rouse.
1 need scarcely add that the circum-
stance that principal cause of insects
plagues-the weather-is beyond our
control, affords no argument against the
use of such means of keeping them under
as are within our power to influence.
Chief among these means seems to be
the preservation of those vivacious in
habitants of Jur woods and gardens,
some shy, some impertinent, but all lex
cept sparrows) delightful, our wild birds.
London Spectator.