The number of insects of different kinds which live in ants' nests, either
as scavengers, stray visitors who have found a lodging for the moment, as
guests carefully taken care of and appreciated by the ants, or as lodgers,
either tolerated or hostile to their hosts and persecuted, and parasites,
is very great. The most interesting of these from the ordinary observer's
point of view are the true guests and the lodgers. The true guests are
carefully attended to by the ants; they include such insects as the
_Aphides_ or plant lice, and others which the ants use as "cows" to secure
the saccharine juices which they can obtain from them, and also certain
strange beetles which have tufts of golden hairs on their body, which the
ants lick--on account of what E. Wasmann[2] calls the etherealized oil {89}
given off by them. These beetles are fairly numerous and belong to several
quite distinct families; the one which perhaps is amongst the most
interesting is a creature called _Lomechusa strumosa_. This insect has
rather an interesting history in connexion with our British fauna. It used
to be considered as an indigenous insect, but so many years passed without
any one finding it, that the old records were suspected as doubtful, and it
was removed from the list of British species. In 1906, however, it was
rediscovered near Woking in a nest of _Formica sanguinea_ (pl. A, 1, 2, 3),
one of the large red ants, by Mr. H. Donisthorpe. The life-history of
_Lomechusa_ is a very curious one: it is taken great care of by the ants,
and its larvae are even placed by them with their own, on which it feeds.
Its numbers are kept down apparently by the overzeal of the ants to take
care of them. The ants bring their own pupae up frequently to obtain light
and air and with them it brings up the _Lomechusa_ pupae--this seems not to
suit the latter and results in the death of many of them. It is a most
interesting case of how a due balance can be maintained, and what might
prove an enemy {90} kept in his proper place by kind intentions. There are
also in ants' nests what Dr. Wasmann calls "tolerated lodgers"; these are
mostly creatures which are supposed to escape the notice of the ants,
either by their small size or by their slow, lethargic, or on the other
hand very rapid movements--these in many cases act as scavengers, living on
the dead bodies of insects, etc., brought in by the ants.
The hostile lodgers are real enemies to the ants and devour their brood,
and in consequence they are always at war with each other. These creatures
generally resemble the ants considerably in form and colour and especially
in their movements.
Besides these lodgers there are numerous parasites of the ants, such as
mites, etc., so that an ant colony is a very wonderful mixture of diverse
inhabitants. The distinctions given above as to the habits of the various
lodgers are not always kept up, as, in some, two or more of these habits
are combined. The whole study of ants and their guests is a most
fascinating one: many of the latter are great rarities and much sought
after by collectors. Unfortunately, the great {91} drawback in collecting
them is the havoc caused to the nests of the ants. These structures have
been the result of enormous labour on the part of these little creatures,
and one cannot regard their destruction without sincere regret. I think any
one who, when collecting beetles, disturbs a large nest of the little
garden ant (_Lasius niger_) or the little yellow ant (_Lasius flavus_) by
turning over a stone, as the writer has often done himself, must have
experienced a like regret at having broken up all the beautiful passages
and galleries which the ants have constructed so carefully.
* * * * *
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