94 



KNOWLEDGE. 



[May 2, 1892. 



ANTS' COMPANIONS-I. 



By E. A. BuTLEK. 



IT has already been pointed out that an Ants' nest may 

 contain more than one kind of insect, and we have 

 shown how some Ants maybe associated with others 

 as guests, parasites, or auxiliaries. But when we 

 have shown this, we have by no means come to the 

 end of the matter : other insects, structurally imlike Ants, 

 are also to be found in the nests intermixed with the true 

 proprietors, and the aUen population of this kind may, in 

 a large community, be considerable. In the nests of the 

 various European Ants there have been found nearly six 

 hundred different kinds of insects other than Ants, and even 

 this long list does not quite exhaust the catalogue of visitors ; 

 sundry species of invertebrate animals which are not 

 insects, such as crustaceans, mites, &c., must be added to 

 comi^lete the total. Of the creatures hitherto registered 

 as occurring in Ants' nests, however, by far the greater 

 number are true insects, belonging to the order of beetles 

 (Coleoptera). Some of these are, no doubt, accidental 

 visitors and not true inhabitants : still, many are genuine 

 lodgers m the nests, and some are found only in such 

 situations. A very large proportion of the Ants'-nest 

 beetles, again, are representatives of a single section of 

 that great order, the division called Brachelytra, or Eove- 

 Beetles. The scientific name of the group means " short 

 wLng covers," and refers to one of the most distinctive 

 characteristics of the beetles (see Fig. 1 ) : they carry their 

 wings neatly packed away under 

 two small squarish covers or elytra, 

 which represent the fore wings, 

 but which do not cover the abdomen 

 as they do in most beetles, but lie 

 over its extreme fore-part only, 

 leaving all the rest exposed, giving 

 thereby an earwig-like appearance 

 to the larger members of the 

 group, as was pointed out in the 

 article on earwigs some months 

 ago. Beetles of this kind are 

 extremely numerous in the British 

 Islands, where they usually act 

 the part of scavengers, devouring 

 carrion, dung, rotten fungi, and 

 other animal and vegetable refuse. 

 It is chiefly small species of 

 these insects that inhabit Ants' 

 nests, creatures scarcely larger, 

 and sometimes much smaller, 



than the Ants themselves. Most people have probably 

 noticed certain small species of Brachelytra, for an 

 exceptionally warm and sunshiny day in early spring is 

 sure to entice swarms of them from their hiding-places, 

 when they will gaily disport themselves in our streets, 

 running rapidly over the ground, or spreading their filmy 

 wings and sailing through the air regardless of obstacles, 

 often, therefore, proving themselves an annoyance by 

 getting into the eyes of passers-by. The " fiy in the eye " 

 as often as not consists of these tiny insects. Such species 

 would as a rule, however, not be the particular kinds that 

 are found in Ants' nests, though they will serve very well 

 to give a general idea of the form of these latter. 



The present season of the year is one of the best times 

 to find these brachelytrous Ants' guests, and as the 

 method of search for them is simple, a few words on the 

 subject may perhaps incline some of our readers to look 

 for them. The nests of the Wood Ant {Foniiica ;■»/'<() are 

 some of the easiest and most protitalDle to commence 



Fig. 1. — Atemeles 

 emarr/iiiatnx, a beetle 

 living in Ants' nests, 

 nuiguiiic-d 8 diiuneters. 



operations upon. The mounds of these insects will now 

 be just beginning to rise, the Ants waking to renewed 

 vigour after their winter rest, and fortunately it will not 

 be necessary to pull the nest to pieces, or otherwise greatly 

 interfere with the labours of the workers in order to find 

 the beetles : such an operation would be both disagreeable 

 and needlessly destructive. All that has to be done is to 

 select a few bricks or large flat stones, and place them on 

 the nest sloping round its sides ; a few broken bits of 

 wood, such as fragments of dead branches, may usefully 

 be added on the top of the nest, and a number of nests 

 within easy distance of one another may be treated in a 

 similar way. These pieces of brick, stone, and wood are 

 intended to act as traps to induce the beetles to congregate 

 on their under surfaces. A few days after the traps have 

 been laid, the nests may be visited again, when it will 

 most likely be found that the objects deposited are partially 

 covered, by means of the labour of the Ants, with fi'agments 

 similar to those that compose the rest of the mound. The 

 traps may now be carefully but quickly lifted, one by one, 

 and at once transferred in an inverted position to a cloth 

 or a large sheet of paper, so that the insects upon them 

 may be more easily seen, and have less chance of escape. 

 Probably many Ants wiU be found clinging to the stones, 

 but a quick eye will soon distinguish here and there 

 amongst them strangers of some sort or other, which will 

 probably turn out to be some of the beetles aforesaid. If 

 it is desired to preserve the beetles, they may be gently 

 removed and transferred to a bottle containing a few lumps 

 of cyanide of potassium covered with pads of blotting 

 paper ; the poisonous vapour from this will soon kill them, 

 and they may then be gummed on card for preservation 

 and examination. As most of them are active in their 

 movements, it will require a little dexterity to prevent their 

 escape, and secure their safe transfer to the killing bottle. 

 The fragments of stick at the top of the nest may be tapped 

 or shaken over the cloth, or over a piece of Avhite paper, 

 when any insects that are in hiding will come tumbling 

 out and may be secured. The stones and other traps may 

 now be replaced, and the nests visited again at intervals 

 during the siariug or early summer, when no doubt other 

 specimens will be obtained. It is best to visit the nests 

 early in the day, before ten o'clock in the morning being, 

 according to the late Mr. .lanson, the best time to find the 

 beetles. Of course, the method of procedure will be 

 varied with the character of the nest ; in the case of those 

 Ants that do not throw up mounds of vegetable fragments, 

 search must be made around the nest, and under any 

 sheltering objects that may happen to lie about in the 

 immediate neighbourhood. If the nest is imder a stone, 

 lifting this will often disclose some of the visitors, and 

 again, the " runs " of the Ants may be profitably inspected. 

 The terms ou which the beetles are associated with the 

 Ants do not appear to be the same in all cases, and indeed 

 in many instances it cannot be said to be satisfactorily 

 determined what the terms are. Speaking generally, it is 

 obvious that, to say the least, the presence of the beetles 

 must in all cases be tolerated ; for such is the energy and 

 courage of Ants that they are not likely tamely to submit 

 to the intrusion of interlopers which are decidedly distaste- 

 ful ; such would be at once attacked and killed, the jaws 

 of the workers being quite capable of thus executing the 

 capital sentence. Mere toleration and indifference, how- 

 ever, by no means represents the attitude of the Ants in 

 all cases ; in some instances there seems to be a certain 

 amount of distrust and suspicion, but in others quite the 

 reverse. Some are on terms of the closest intimacy with 

 their hosts, by whom they are treated carefully and 

 tenderly, and their presence is evidently valued. Speaking 



