Evening star., 1925-08-10
THIS AND THAT
BY CHARLES E. TRACEWELL.

struck by about a score or slave
makers hunting the same spot, and
evidently not In search of food; they
approached and were vigorously re-
pulsed by an Independent community
of the slave species; sometimes as
many as three of these ants clinging
to the legs of the slave making F..
sanguinea.
"The latter ruthlessly killed their
small opponents and carried their
dead bodies as food to their nest, 20
yards distant: but they were pre-
vented from getting any pupae to
rear as slaves.
I then dug up small parcel of
pupae from another nest, and put
them down on bare spot near the
place Of combat; they were eagerly
seized and carried off by the tyrants.
who perhaps fancied that, after all.
they had been victorious in their late
combat"
Swiss ants get a great deal more
out of their slaves than English
ants, Darwin concludes. He says:
Let 1t be observed what a con-
trast the instructive habits of +.
sanSuinea present with those of the
continental r. rufescens. The latter
does not build its own nest, does not
determine it's own migrations. does
| not collect food for itself or it's
| young, and cannot even feed itself;
| it is absolutely dependent on its
numerous slaves.
"Formica sanguinea. on the other
| hand, possesses much fewer slaves;
the masters determine when
and where a new nest shall be
formed and when they migrate, the
masters carry the slaves. Both in
Switzerland and England the slaves
seem 10 have the exclusive care of
the larvae. and the masters alone go
on slave making expeditions.
I'm Switzerland the slaves and
masters work together, making and
| bringing materials for the nest; both,
but chiefly the slaves, tesd and milk.
as ii may be called, their aphides
and thus both collect food. In Eng
land the masters alone usually leave
the nest to collect building materials
and food for themselves, their slaves
and larvae. So that the masters in
this country receive much less serv-
| ice from their slaves than they do in
Switzerland.
BY what steps the instinct of F.
sanguinea originated | will. not pre-
| tend to conjecture" our author con-
/ tinues, Immediately on going on TO
! do so. But as ants which are not
| slave makers will, as ! have seen,
carry off the pupae of other species
| If scattered near their nests, 1t is
possible that such pupae originally
| stored as food might become de-
veloped: and the foreign ants thus
unintentionally reared would then
| follow their proper instincts, and do
what work they could
Imagine the delighted wonder OF
the first slave-makers Hot dog"
shouted Henry VIII. king of the Ruff
| fans. Look at these babies cook
ing our meals, Thanks, old chaps
you have selected good jobs for your
self" But to return to Darwin:
IF their presence proved useful to
the species which had seized them
| If ii were more advantageous to this
species to capture workers than to
procreate them-the habit of collecting
pupae, originally for food, might by
natural selection be strengthened and
| rendered permanent for the very
different purpose of raising slaves.
when the instinct was once ac-
| quired, If carried out to a much less
| extent even than our British F. san
| guinea, which. as we have seen, l.
less aided by it's slaves than the
same species in Switzerland, natural
| selection might Increase and modify
the 'tnstinct-always supposinG each
modification TO be of use to the
species-until an ant was formed as
abjectly dependent on its slaves as
| is the Formica rufescens"
Well, II might-but l find il pretty
| hard to imagine that board meeting
! OF ants wherein II was decided to be
! more advantageous to the species tc
| capture workers than to procreate
| them,