There are two species of Cyphomyrmex recorded from California, both ground-nesting and infrequently encountered. These fungus-growing ants collect caterpillar frass and other organic matter, on which they cultivate fungal mycelia or (in some species) yeasts.
Species identification: keys in Snelling and Longino (1992). Additional references: De Andrade (2003), Kempf (1964d, 1966), Schultz et al. (2002), Weber (1972).
Canindeyú , Central (ALWC, MHNG).
Canindeyú (ALWC).
Alto Paraná (ALWC).
Amambay (ALWC, USNM).
Canindeyú , San Pedro (ALWC, USNM).
Boquerón (ALWC, USNM).
Amambay, Canindeyú (ALWC, LACM, USNM).
[[ worker ]] Kopf viereckig, vorne etwas schmaeler als hinten, sehr an die Cryptoceriden erinnernd. Mandibeln ziemlich schmal, gegen das Ende wenig breiter, flachgedrueckt, der Kaurand schneidig und ungezaehnt. Clypeus und Stirnfeld (zusammengenommen, da die Grenze zwischen beiden nicht ausgepraegt ist), vorne beiderseits nicht bis zur Ausrandung der Mandibeln reichend, da die Stirnleisten dazwischen liegen, nach hinten lang dreieckig bis zur Hoehe der Augen verlaengert, flach, etwas vertieft, die Seitenraender sehr wenig nach aussen gebogen, das hintere Eck nicht scharf ausgepraegt. Die Stirnleisten beginnen am Vorderrande des Kopfes, begrenzen beiderseits den Clypeus, ueberragen etwas den Seitenrand des Kopfes, ihr Aussenrand ist bis zur Hoehe des Endes des Stirnfeldes bogig, nach aussen convex, weiter nach hinten sind sie dann stark nach einwaerts gebogen, erweitern sich wieder und ziehen ueber den Augen, fast so weit von einander abstehend, als die Seitenraender des Kopfes, nach hinten divergirend zu den Hinterecken des Kopfes (aehnlich so wie bei den Cryptoceriden). Fuehler zwoelfgliedrig, ihr Schaft am Ende maessig keulig verdickt, ihre Geissel etwas keulenfoermig, die ersteren Glieder klein, die letzteren etwas groesser, das letzte zeichnet sich durch besondere. Groesse aus, es ist spindelfoermig und nimmt etwa den dritten Theil der Laenge der Geissel ein. Die Stirne ist wegen den weit von einander abstehenden Stirnleisten sehr breit, zwischen den Augen unregelmaessig quer vertieft und geht in den von den Stirnleisten seitlich begrenzten Scheitel ueber .. Die Netzaugen convex, unter den Stirnleisten, etwa in der Mitte des Seitenrandes des Kopfes. Ocellen habe ich nicht gefunden. Der hinten maessig ausgebuchtete Scheitel mit zwei ziemlich kurzen Laengsleisten und zwar so gestellt, dass diese zwei und die den Scheitel Seitlich begrenzenden zwei Stirnleisten in ziemlich gleicher Entfernung von einander liegen. Thorax vorne am breitesten, zwischen dem Meso- und Metanotum stark eingeschnuert, das Pronotum vom Mesonotum ebenfalls durch eine seichte Furche getrennt. Das Pro- und Mesonotum zusammen (den vordersten Theil des Pronotums, der sich mit dem Kopfe verbindet, abgerechnet), von oben gesehen, viereckig, vorne breiter als hinten mit geraden Seiten; Pronotum vorne seitlich in stumpfe Ecken erweitert, oben bildet der hintere Theil des Pronotum mit dem Mesonotum eine concave Flaeche, welche seitlich beiderseits von einer welligen Leiste begrenzt ist; die beiden Leisten gehen in die den Hinterrand des Mesonotum begrenzende Leiste ueber. Das Metanotum ist etwas niedriger als der vordere Theil des Thorax, die Basalflaeche ist horizontal und die abschuessige Flaeche fast senkrecht, beide Flaechen sind beiderseits von einer schwachen Leiste begrenzt. Das eingliedrige Stielchen ist vorne dick stielfoermig, hinten stark knotig verdickt, breiter als hoch, etwas kubisch, jedoch ohne scharfe Kanten und Ecken, oben hinten mit zwei kleinen, rundlichen Hoeckern. Der Hinterleib ist kurz oval, das erste Segment bedeckt fast den ganzen Hinterleib.
Cyphomyrmex Mayr, 1862: 690 (Type: Cyphomyrmex minutus Mayr , 1862 = C. rimosus minutus Mayr , worker, monobasic). - Kempf, 1962: 29-30 (Syn.).
Cyphomyrmex (Cyphomyrmex) : Emery, 1913: 251. - Emery, 1922: 340-342.
Cyphomyrmex (Cyphomannia) Weber, 1938: 183 (Type: Cyphomyrmex (Cyphomannia) laevigatus Weber , 1938, worker, by original designation and monobasic).
As regards the generic features, the reader is referred to Emery's diagnosis in the Myrmicinae section of Genera Insectorum (1922: 341). It needs only one correction that concerns the development of the preocular carinae, which either curve mesad above eyes in the usual Attine fashion (most species of the rimosus -group), or run caudad as a straight pleat to the occipital corner where they join, after forming a loop, the posterior extension of the frontal carinae (all species of the strigatusgroup).
The subgenus Cyphomannia was sunk as a synonym, because its type species, laevigatas, belongs to the same group that contains the type species of the nominal subgenus, rimosus minutus (cf. Kempf, 1962: 29-30).
To date, Cyphomyrmex comprehends 28 species and 17 subspecies and varieties, 12 of which are attached to rimosus , 3 to bigibbosus , 1 to salvini and 1 to olitor . As shown previously (Kempf, 1962: 30) the genus is divisible into two rather welldefined species groups, according to characters found in the worker and female caste:
I. Group of rimosus : Preocular carina curving mesad above eyes, not joining up with the postocular carina, which extends from the occipital corner to posterior or inferior border of eye (this character is not well-expressed in longiscapus and allies, which resemble the strigatus -group in this respect); mandibles with 5 teeth only; two or no median pronotal tubercles present. A revision of this group will be taken up in Part li of the presenl study, to be published at a later date.
II. Group of strigatus : Preocular carina extending all the way back to the occipital corner, forming the inferior border of the antennal scrobe; mandibles with 7 or more teeth, gradually diminishing in size towards base; a single median pronotal tubercle usually well-developed in the worker caste.
The present study concerns itself with this group, which comprises the following species and new synonyms (W = worker; F = female; M = male):
Types of all forms, with the exception of strigatus , bigibbosus , vallensis and lilloanus , have been examined.
The group as a whole, is confined to continental South America, and attains its highest degree of diversity in southeastern Brazil and northern Argentina.
On the species level, the present review recognizes 15 species, one of them being described as new to science. Whereas two forms hitherto considered as subspecies are raised to specific rank, four forms are placed into synonymy. The above proposed arrangement is not to be considered as final. Several species, especially those in the vicinity of olitor , viz. daguerrei , vallensis , bruchi and nemei , are still known only from scanty type material. Inasmuch as the extent of their infraspecific variability has not yet been explored, these species continue subject to doubt and hesitation. That this range is appreciable seems to be suggested by olitor , of which copious material is known from southeastern Brazil.
The revision undertaken in the following pages deals exclusively with the worker and female caste. The males are completely set aside, because they are known of only half of the described species. In addition, the scarce material available does not permit a comparative treatment, without which isolated descriptions are practically useless.
Note on measurements. - The total length is the sum of the maximum lengths of head with closed mandibles, thorax, petiole, postpetiole and normally expanded gaster. The head length is the maximum length of the head capsule, in full-face view, between two parallel lines drawn across the anteriormost point of clypeus and the posteriormost point of occiput or occipital lobes: the head width is the maximum width of the head capsule behind the eyes; the thorax length (Weber's length) is obtained in profile, and consists of the distance between the anteriormost point of the pronotum proper and the metasternal angle.
Key to the species for workers
( C. nemei and vallensis are not included. The worker of occultus is still unknown).
1. Promesonohim without tubercles.............14. lilloanus Kusnezov
- Promesonotum with at least some of the tubercles developed..... 2
2. Occipital lobes distinctly auriculate (Figs. 1-6), protruding also in profile (Figs. 44-49); antennal scrobe opaque with indistinct microsculpture................................................. 3
- Occipital lobes not auriculate (Figs. 7-12), or if somewhat projecting in full-face view, they do not project in profile (Figs. 50-55); antennal scrobe superficially reticulate and somewhat shining............. 8
3. Tergum 1 of gaster laterally carinate with two additional longitudinal carinae on disc......................................... 4
- Tergum I of gaster lacking discal carinae, lateral ones usually not well-developed ............................................ 6
4. Occipital lobes horn-like, longer than their maximum width (Fig. 1); mesonotum with high, acute conical spines (Fig. 13)............ 1. auritus Mayr
- Occipital lobes distinctly shorter than their maximum width (Figs. 4, 6); mesonotum bluntly tuberculata (Figs. 17, 18).............. 5
5. Frontal lobes nearly straight and scarcely constricted behind, subcontinuous with frontal carinae (Fig. 4); hind femora noticeably broadened and angulate beneath at basal third, with a prominent foliaceous rim on posterior border............ 3. plaumanni Kempf
- Frontal lobes more rounded and distinctly constricted behind, not continuous with frontal carinae (Fig. 6); hind femora not conspicuously broadened nor angulate at basal third, lacking a foliaceous rim on posterior border.............. 2. strigatus Mayr
6. Scape in repose surpassing occipital lobe (Fig. 3); pronotal and posterior mesonotal tubercles well-developed and conical; epinotum in profile angulate or dentate (Fig. 20)....... 4. paniscus Wheeler
- Scape in repose not surpassing occipital lobe (Figs. 2, 5); only anterior mesonotal tubercles well-developed, high and conical, all other very low, tumuliform (Figs. 15, 16); epinotum in profile rounded and unarmed ............................................... 7
7. Posterior border of postpetiole deeply excised (Fig. 30)........... 5. bigibbosus Emery
- Posterior border of postpetiole straight (Fig. 31)................. 6. faunulus Wheeler
8. Basal face of epinotum very short and completely unarmed (Fig. 14); frontal carinae covering the upper orbit of eye in full-face view (Fig. 12); inferior occipital corner with a foliaceous rim (Fig. 55).. ....................................... 12. lectus Forel
- Basal face of epinotum almost as long as declivous face, bearing posteriorly a pair of at least feeb'e tubercles or teeth; frontal carinae less expanded laterad, not reaching the upper orbit of eye in fullface view; inferior corner of occiput without a foliaceous rim.... 9
9. Posterior loop of antennal scrobe only vestigially marginate, its lateral border not coinciding with lateral border of head (Fig. 11); antero-inferior corner of pronotum produced foreward in a short spine (Fig. 24)................................ 7. morschi Emery
- Posterior loop of antennal scrobe sharply marginate, its lateral border coinciding with lateral border of head; antero-inferior corner of pronotum subrectangular................................ 10
10. Scape in repose conspicuously surpassing the occipital corner (Fig. 8); hind femora longer than maximum length of head capsule, ventrally not dilated nor carinate at basal third..................
8. daguerrei Santschi
- Scape in repose barely if at all surpassing the occipital corner; hind femora not longer than maximum length of head capsule, ventrally dilated or angulate and carinate at basal third................. 11
11. Lateral lobes of petiole ventrally deeply excavate, outer borders broadly foliaceous; midpronotal and antero-lateral mesonotal tubercles indistinct, dorsum of thorax in profile strikingly flat (Fig. 21)..... 10. bruchi Santschi
- Lateral obes of petiole ventrally at most shallowly excavate and mostly solid; midpronotal and antero-lateral mesonotal tubercles distinct, dorsum of thorax in profile convex with prominent tubercles and deeper impressions (Figs. 19, 23)............... 9. olitor Forel
Key to the known females
1. Tergum 1 of gaster with 4 longitudinal carinae, two on disc and one on each side. ............................................ 2
- Tergum I cf gaster lacking a pair of longitudinal carinae on disc; sides either marginate or immarginate.......................... 3
2. Occipital lobes long, horn-like, longer than their width at base; midpronotal tubercles usually present; epinotal spines well-developed 1. auritus Mayr
- Occipital lobes short and rounded, shorter than their width at base; midpronotal tubercles always absent; epinotum practically unarmed.. 2. strigatus Mayr
3. Antennal scrobe densely but indistinctly granulate and opaque; paraptera of mesonotum with a tooth that either projects upward or caudad ................................................. 4
- Antennal scrobe sharply and distinctly reticulate and somewhat shining; paraptera of mesonotum flattened above, its lateral and posterior margin completely rounded without a projecting tooth.. 6
4. Antennal scape in repose surpassing occipital lobes; epinotal spines well developed; lateral borders of gastric tergum 1 marginate...... 4. paniscus Wheeler
- Antennal scape in repose not surpassing occipital lobes; epinotal spines at best vestigial; lateral borders of gastric tergum I immarginate ............................................... 5
5. Posterior border of postpetiole with a deep mesial excision, flanked by prominent tubercles...................... 5. bigibbosus Emery
- Posterior border of postpetiole straight, without a mesial excision.. 6. faunulus Wheeler
6. Hind femora longer than head capsule, slender, ventrally not gradually dilated towards basal third nor angulate, their posterior ventral border not carinate; antennal scape in repose surpassing occipital angle or lobe .............................................. 7
- Hind femora shorter than head capsule, ventrally gradually dilated towards basal third where they form a more or less distinct angle; their postero-ventral border carinate to crested; antennal scape in repose not surpassing occipital lobe............................. 8
7. Petiole longer than broad, its dorsum with a pair of prominent and laterally compressed teeth; maximum diameter of eyes nearly one third of head length............................ 15. occultusn. sp.
- Petiole broader than long, dorsally completely flattened without teeth; maximum diameter of eyes less than one fourth of head length ...................................... 7. morschi Emery
8. Longitudinal furrow on tergum 1 of gaster broad and distinct, traversed by regulae; epinotal spines almost obsolete............. 13. nemei Kusnezov
- Longitudinal furrow on tergum 1 of gaster less distinctly impressed, not traversed by regulae; epinotal spines usually fairly well developed 9. olitor Forel
Cyphomyrmex is a genus of fungus-growing ants found primarily in South and Central America. However, some species do come up to the southern portion of North America. They grow a variety of fungi in the tribe Leucocoprineae. Most fungal gardens are grown in small nodules, some species to cultivate entire mycelium, though. Colonies are monogynous and are relatively small with about 100 workers on average.[2]
This genus is within the subfamily Myrmicinae and the tribe Attini. Cyphomyrmex is a more basal part of this phylogenetic relationship. With more recent phylogenetic studies, more derived genera are placed ahead of this genus, now making it sister to the genus Mycetophylax.[3] The fungi that are grown by attine ants, like Cyphomyrmex, follow similar diversification as their ant cultivators.[4] Also, chemicals used throughout the attine ants are derived from one another. So, those used by Cyphomyrmex provided a base plan for more complex mixtures that are found in higher genera, like Trachymyrmex. This helps to relate attine ants to one another and even separate species as chemical profiles can be particularly unique.[5]
The frontal carinae on the head form a shield which is quite diagnostic for this genus. On the mesosoma, there are a series of blunt tubercles lining it. This genus is divided into two complexes, the strigatus and rimosus complex. The strigatus complex is limited to South America, while the rimosus complex ranges from southern North America to South America. Species in the rimosus group can be noted by their anteriorly open antennal scrobe and the five teeth on their mandibles. While strigatus has a closed anterior antennal scrobe with six or more teeth on the mandibles.[6][7]
As with all ants, they undergo complete metamorphosis. Their diet varies throughout development.
Larvae:
They are primarily mycophagous.[8] They are commonly groomed by workers which promotes fungal growth on their integument. This fungal growth can take both the mycelial and yeast form. As larvae develop through multiple instars, they do not differ drastically in their morphology. The main, observable difference is that they become larger and more rotund as they age.[9]
Workers:
As is found across genera, as ant workers age they progressively move out of the colony. Younger workers are primarily nurses, while older ones are foragers.[10][11] They also assist with ecdysis for the larvae as they molt or emerge from eggs. In Cyphomyrmex, workers are mostly mycophagous, like the larvae. Younger workers do receive sugary substances from older workers through trophallaxis. These older workers have the most diverse diet, consisting of sugary substances derived mostly from plants found from their foraging trips.[8]
Queens:
Founding queens have a low level of fat reserves when compared to other genera. This is because they rely on their fungal gardens to provide these extra nutrients the first generation of workers will need.[12] There is normally a monogynous colony structure within Cyphomyrmex. The queen’s diet is primarily mycophagous, however some sugars are fed to her from the older, foraging workers.[8]
The rimosus group is known for their cultivation of nodules of fungus, also called yeast gardens. This type of growth is known for clusters of small patches of fungus on irregularly shaped nodules full of single-celled yeast-like cells. This type of growth is unique in association with Cyphomyrmex ants. So, it is thought of as a form of domestication for Leucocoprineaceous fungi as they naturally grow in the mycelium form.[13]
Workers grow nodules of fungus, in the tribe Leucocoprineae,[2] and they perform this in stages. First, workers will clean a portion of the ground and place insect feces, an old exoskeleton, or another organic item like a leaf.[2][8] Then a worker will regurgitate fluids from her crop and add anal fluids. She then lets it dry on the surface. Other workers, or the same one, will repeat this process until the ball is about 0.8 mm. At this point, it is transplanted to where other nodules are growing with fungi. This new one is rubbed on established colonies and then placed on the ground, starting a new, small garden.[8] Gardens can also be created hanging from roots on the ceiling of a nest, showing plasticity in the behavior of nest making.[14]
Workers also can have highly aggressive behavior towards unwanted guests. Specialized wasps in the family Diapriidae parasitize larvae and can induce a relatively large mortality rate, with about 16% of all larvae being infected. Any newly emerged wasps found in the brood piles are almost immediately attacked.[15]
Most Cyphomyrmex species are found to contain 3-octanol.[16][5] This is thought to act as an alarm signal across species. Traces of nonanal are also found within the genus. Another common chemical group are farnesenes. It contributes to trail following behaviors, and potentially more importantly, influences agriculture practices. Some of the nodule-making species contain low diversity and overall levels of farnesenes. While mycelium growers are found to have a high diversity of this chemical group in their gaster. The presence of farnesenes seems to be unique to Cyphomyrmex among the fungus-growing ants; however, other genera across the family Formicidae also possess it.[16]
Inquilines of Cyphomyrmex can influence the behavior of their hosts. As observed in host associations between C. cornutus and its social parasite Megalomyrmex mondabora, alkaloids in the venom of the parasite cause less aggressive behavior in their host. Sometimes C. cornutus even plays dead when they are stung or in contact with their parasite, showing that the venom has evolved to not be extremely toxic to them and simply manipulate social behavior.[17]
The fungi that the ants interact with can also produce important chemicals. Some fungal gardens can produce diketopiperazines, which has antifungal abilities. This is through to either protect the fungi or the ants from other potentially harmful species. Diketopiperazines are thought to possess some antibacterial and antiviral abilities too.[18]
Common nest sites for species can range from in the soil, under rotting logs, within hollow and dead twigs. Some species have specialized nesting habits, such as C. longiscapus. They create swallow nest-like structures that hang underneath overhangs. It is made of soil or clay. The main entrance leads directly to their fungal garden, which should leave them susceptible to desiccation; but they only live in moist habitats so their gardens remain wet.[2] Some inhabit arid environments while others are in wetter conditions, like C. longiscapus. Another species, C. transversus, was observed nesting inside and around dry coconuts.[14] Therefore, a variety of species can found colonies in a wide range of habitats and ecosystems.
They range from Central South America, reaching as south as Argentina. They also reach up into North America, stretching from Texas up to California and even east to Florida.[19]
Cyphomyrmex is a genus of fungus-growing ants found primarily in South and Central America. However, some species do come up to the southern portion of North America. They grow a variety of fungi in the tribe Leucocoprineae. Most fungal gardens are grown in small nodules, some species to cultivate entire mycelium, though. Colonies are monogynous and are relatively small with about 100 workers on average.
Cyphomyrmex é um gênero de insetos, pertencente a família Formicidae.[1]
Cyphomyrmex é um gênero de insetos, pertencente a família Formicidae.
