Wasps, Social and SolitaryPeckham, George W. (George Williams)
Science
Wasps, Social and Solitary
Peckham, George W. (George Williams)
Wasps
Thus in our second example, she stung the first three segments in
the regular order, the third, the second, and lastly (and most
persistently) the first. She then went on, without a pause, to sting
the fourth, fifth, sixth, and seventh, stopping at this point and
leaving the posterior segments untouched. In our first example, it will
be remembered, the middle segments were spared. The stinging being
completed, she proceeded to the process known as _malaxation_, which
consists in repeatedly squeezing the neck of the caterpillar, or other
victim, between the mandibles, the subject of the treatment being
turned around and around so that all sides may be equally affected.
[Illustration: AMMOPHILA URNARIA STINGING CATERPILLAR]
In our third case a caterpillar which we had caught was placed in front
of a wasp just after she had carried the second larva into her nest.
She seemed rather indifferent to it, passing it once or twice as she
ran about, but finally picked it up and gave it one prolonged sting
between the third and fourth segments. She then spent a long time in
squeezing the neck, pinching it again and again, after which it was
left on the ground; and as she showed no further interest in it we
carried it home for further study.
In the three captures, then, that came under our observation, all
the caterpillars being of the same species and almost exactly of the
same size, three different methods were employed. In the first, seven
stings were given at the extremities, the middle segments being left
untouched, and no malaxation was practiced. In the second, seven
stings again, but given in the anterior and middle segments, followed
by slight malaxation. In the third, only one sting was given, but the
malaxation was prolonged and severe.
Let us now compare these variations with those of Fabre. In his first
case the sting entered at twelve different points, beginning between
the first and second segments and progressing regularly backward. There
was no malaxation. In his second example the third, second, and first
segments were stung in the order given, and thereafter each succeeding
segment up to the ninth, nine stings being given in all, with careful
malaxation following. In his later experiments, which seem to have been
numerous, he found that as a usual thing all the segments were stung,
although the posterior three or four were occasionally spared, but that
the order in which they were operated upon, as well as the amount of
malaxation, was very variable.
Our conclusions, then, as to Ammophila’s methods of stinging agree
fairly well with those of Fabre; but there is one important exception.
In his cases the middle segments, upon one of which the egg is laid
in our species as well as in his, were invariably stung, and this he
considers a point of extreme importance. In one of our cases the middle
segments were not touched.
[Illustration: CATERPILLAR WITH EGG OF AMMOPHILA URNARIA]
Public-domain text, read in full here on John Shaqi.
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