Article beginning on page 111.
Psyche 9:111-115, 1900.

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PSYCHES
THE RABITS OF MYRMECOPHILA NEBRASCENSIS BRUNER.* RY WTLLlAM MORTON WHEELER, AUSTIN, TEXAS. Among the many insects now known to
live as guests in the nests of ants the
diminutive crickets of the genus Myrmc-
c~phila are in several respects rcn~alk- able. First, they are cited as the only
members of the great Orthopteran orclcr
that have come to live with the most
social of the Hymenoptera + ; second,
the males of the species of Myrmecophila have long been all but unknown, and
third, the nature of the relationship of these little Gryllids to their emmet
hosts has not been determined up to the
present time.
In the November number of PSYCHE
for 1899, Mr. Scudder published a
monograph of the known North Ameri-
can species of Myrmecophila. This
will uncloubtcdly encourage further work on this interesting genus along taxo-
nomic lines. In the present paper I
wish to call attention to the peculiar
habits of one of the species, M neb-
*Contributionsfrom the Zoological Laboratory of the University of Texas. No, 7. Director, W. M. Wheeler. ]-This statement now requires qualification. In a forth.. coming paper I shall describe aiiother Orthopteran genus, represented by a diminutive cuck~oncli, which lives as a myrniecophile in (he fungus gardens of the leaf-cutiiiag ant ul Texas (Ah fervens Say),
rascensis Bruner, which is very common
in the vicinity of Austin, Texas. Here
it may be found in the nests of no less
than five very different species of ants. It is most abundant in company with
Formica fitsca, var. ncorztfiba~bis Mayr - sometimes as many as 20 or 30 individ-
uals occurring in a single nest -less
abundant in the nests of the Texan agri- cultural ant (Pogonomyrmex iarbatiis
Sm.) -and rare in the nests of Cumjo-
7Wbt~ castaneus Latr., the Poncrine Pachy- condyla hay-fax Fab. and a species of
Crema~to~ster. Its true host in this
vicinity is undoubtedly .I+; f'usca var. nee?-~tfihariis, which dig's its galleries under stones on moderately moist hill-
slopes in the shade of the cedars and
live oaks. Since nests of all the clif-
fcrcnt species of ants above mentioned
may be found very near one another, it
is probable that the crickets occasion-
ally seen in the nests ol Pachyconclyla
and Carnponotus are vagrants that have
invaded strange lerrilory.
These data on the occurrence of M.
7ieimscen^i.s are of some interest since they extend both Lhe geographical and
symbiotic range of the species. IIither- to, according to the data accumulated




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11 2 PSYCHE. [Odobci, iqm.
by Mr. Scudder,* it was known to
occur in Minnesota (Lugger), Nebraska
(Brnner) and New Mexico (Cockerell).
The addition of one of the Gulf states,
in which no members of the genus had
been found, cairies the species to its
southernmost boundary. Heretofore it
has been taken only in the
nests of
Formica exsectoides Forcl (in New Mex-
ico) and with some ants which Bruner
incorrectly referred to R rz'/a, Per-
gandc believes that it " equally fre-
quents the colonies
of Formica puberula
Em ., Form. integroitles Em., Form. rub;- ginom Em. and possibly other forms
belonging to the great RuFa group." t
The males of the European species
of Myrmecophila are so rare as to be
almost unknown. Scudcler says (loc.
cit., p. 428): " Although two species of the genus are known in Europe, and
one of them is not uncommon, Brunner
von Wattenwyl says the male is un-
known to him, Saussure has but once
seen one, and this was destroyed before
hc could describe the genitalia, and
Fischer of Freiburg has seen the males
of one species only, and in his classical work refers to it only by the words:
lam. supraanalis mihi non rite visa. "
It is, however, figured in Cuvier's Regne Anim., Disc. ed. pi. 82, fig 2." Even
Wasmann, who has devoted special
study to the guests of ants, cites the
medium sized individuals of the Euro-
pean M. acei-voruh as doubtfully be-
longing to the male sex. * In the
United States, however, the males of
Myrmecophila are not uncommon.
Among forty specimens Scndder found
sixteen males, and these represented all but one of the five Nortli American
species.
The males of M. nebrascensis are very
common at Austin.
They bear to the
females, I should say, the ratio of about one to seven or eight.
That the some-
what smaller individuals without oviposi- tors and with a large, apically cleft sub- genital plate are really the males is shown in sections. During April and May
the testes, in active spermatogenesis, to- gether with a huge accessory gland con-
sisting of a radiating tuft of tubules, fill out nearly the whole abdominal cavity
of the insect. The gland must have
some important function connected with
reproduction but this could not be de-
termined.
At this same period of the year the
abdomen of the female Myrmecophila is
found to contain a few very large cllip- tical white eggs, in form and size not
unlike the eggs of the ants among which
the crickets live. I have not been able
to observe the insect in the act of ovi- positing. She probably thrusts her cggs
into the moist compact soil that forms
the walls of the galleries of the ants ' nest. The eggs must hatch about tlie
first of June, as I have seen the young, about one fifth to one fourth grown by




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~ctober, q00.1 PSYCHE. 113
June 22nd.
They are paler and rcla-
lively somewhat narrower than the adults. My observations on the habits of Myr-
mecophila began early in March of the
present year. The little crickets were
taken from the Formica nests and placed
in artificial nests of Pogonomyrmex, an
ant of slower movements and in many
other respects more satisfactory tor pur- poses of observation than the Formica.
At first I used nests consisting oE large- mouthed glass jars containing some earth in which the ants readily dug their gal- leries and chambers, sometimes next to
the glass; but quite as often where
their occupants could not be seen. The
crickets placed on the earth at once
crept down into the galleries and could
be seen only from time to time moving
about unmolested among the ants and
along the walls of the burrows. This
did not satisfy me, so I abandoned these earthen nests for cement nests of the
Janet pattern.
I had no occasion to re-
gret this change as it enabled me to
observe the insects for hours at a time
without disturbing them, especially in
the lamplight, of which both the ants
and the crickets seem very fond. The
following from my notebook is one of a
number of similar obscrvations.
April 3rd.
Placed in the Pogonomyr-
mex nest twenty Myrmccophilas, eight
or ten of which had been squeezed
or had lost one or both saltatory legs
during capture. All the disabled individ- uals were at once seized and dispatched
in so vindictive a manner, that I could
not doubt that the ants were irritated by the pungent neorz!fi1)artis nest-odor still clinging to the crickets. In an instant
all the ants in the compartment of the
nest had gathered in little groups, each devouring a Myrmecophila. The un-
injured crickets made not the slightest
attempt to escape but felt themselves
perfectly at home as soon as they set
foot on the floor of the nest. Their
adaptation to a new -nest and to an ant
of larger size and belonging to an entire- ly different subfamily from their former host, was immediate and complete. With
constantly vibrating antennae they be-
gan dodging in and out among the
little groups of assembled ants. From
time to time one of them would be seen
cautiously approaching an ant, that was
busy with its dinner of Myrinccophila,
and fall to nibbling at its legs or the tip of its abdomel~. There could be no
doubt that the cricket derived some ben- efit from the oily secretion covering the surface of the ant's body. At first the
ant disregarded this nibbling, which
probably resembles the attentions of
the toilet habitually received from sis- ter ants, but the cricket's scrapiug man- dibles and maxillae soon grew annoying
and the ant would either move away or
turn its head, open its mandibles and
make a lunge at the Myrmecophila
like a large dog annoyed by a puppy,
But before the huge mandibles had
closed, the cricket was far away, already nibbling at the abdomen of some other
ant. The cricket can get at only the
legs and abdomen of its host, since the
spreading legs prevent it from reaching




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114 PSYCHE. [October, 1900.
the thorax. It often stands on its hind
legs, as represented in the figure, and
places its fore legs on the ant's leg, in order to reach the femur or tibia. For
very obvious reasons, it avoids nib-
bling at or even approaching the ant's
head. It is always alert, as if perpet-
ually aware of danger and ready to
dodge at the slightest movement made by
the ant.
The crickets do not derive all their
smtenance from cleansing their hosts.
In earthen nests they are often seen
haunting even the galleries that have
been abandoned by the ants, scrutiniz-
ing the walls and nibbling at them from
time to time. There can be no doubt
that they find here the same substance
which covers the ants, for the walls of
the galleries of a populous nest soon be- /ITyrmeco//;//a in Llic act of feeding OIL the integumentary secretion of the agricultural ant. Occasionally in the narrow confines
come greasy from the attrition of the
of an artificial nest the ants do succeed constantly passing ants. Sometimes in capturing and devouring one of their
the crickets may be seen nibbling at
vigilant little guests, but the fact, that dead ants that have been temporarily
of the eleven sound crickets left after
abandoned in the galleries or placed on
the above observation was made, eight the kitchen-midden of the nest. The were still alive June zznd, when I had intestine of a Myrmecophila which I to discontinue my observations for the dissected was found to contain oil-glob- summer, shows that the crickets arc ex- ules and a granular whitish substance. tremely expert in keeping out of danger. It is possible that one or both of these The attitude of the ants during all this may be the products of integumentary time underwent no change so far as I glands like those described by Janet.* could observe, for they would still oc- - * Sur le Systiinegland~~lilire des Fourmis. Compt. Rend. casionally make lunges at the crickets.
I,~I,*. ae P sd. T. 1,8. p. os<i, 1804.




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October, 1900.1 PSk'(-.f,'E 115
1 t is an established fact that ants when moving to a new nest will take with them certain of their guests like their Aphides, and the singular beetles of the genera
Claviger, Pausstis, etc. Myrmecophila
can lay claim to no such consideration.
When a colony of Formica neoi^tfibarbis
moves, the crickets are all left behind. The heavy floods of the past spring
pave me an excellent opportunity to con- vince myself of the truth of this state- ment. Many of the neo?@arbis nests
which I was in the habit of visiting, were submerged during the night by a rapid
rise of one of the creeks near Austin.
The following clay, when the water had
subsided, I found that the nests had
been completely deserted by the ants,
but nearly all of them still contained
numerous Myrmecophila wandering in
and out of the galleries under the stones as if nothing had happened. I have also
seen the crickets left behind in other
neo/$~kr?-bis nests which were on higher ground and had been deserted for rea-
sons unknown to me. These observations
may explain a note quoted by Mr. Scud-
der conccrning M. on'p~ensis Bruner.
Dr. F'lctcher inLo~-med him that this
species is " common in British Columbia
under almost every slab of wood in some
places, whether there are ants there 01- not." I doubt the occurrence of Myrme-
cophila outside of ants' nests.
It is evident from the facts above 1-c-
corded that the ants would gladly forego the company of their little nest-mates,
but unless they resort to moving the
whole colony, they are compelled to
tolerate them for a very simple reason.
The ants with their long bodies, incapable of much lateral flexure, always walk or
run in long, straight or sinuous paths,
and are quite unable to turn sharply
about, whereas the short-bodied crickets move in a complicated zig-zag path
made up of very short lines and abrupt
angles. This seems to be the key to
the symbiosis of the two insects: the
ant and the cricket manage to get on to- gether in the limited space of an ants'
nest because they have very different,
and, as it were, intercligitating inodcs of progression. Since the ants arc quite
able lo clean themselves and one another and even take delight and spend much
time in this employment, they probably
derive little or no advantage from their cricket guests. The crickets, however,
cannot get on without the anis and the
greasy walls of. their burrows. The
symbiosis is thereforcof a unilateral type and would seem to belong in the category of relationships called " Metoekie " or
' Synoekie " by Wasmanil. It is, in
fact, a relationship but slightly in ad- vance of that of the Collembolan Cy-
phodeira (firkin) aitinos 'Sic. which
appears to obtain its entire sustenance
from the walls of the ants' burrows with- out extending ith attentions to the integ- ument of the ants.
University of Texas,
Austin, Tex., June zzncl, 1900.
* Vie Myrm~kophilen imtl 'Tertnit~~l~ilcn. Compt. Rcncl. des S&uces dn 5n;e Cougr. internal. 2001. Ley& 16-21
Sept, 1895. Leyden, ~ 8 ~ 6 p, 412,




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