Polyrhachis

Polyrhachis; Temporal range: 7.246–0 Ma K Pa Eo Ol Mi Pl Miocene – Recent
	Polyrhachis bihamata
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Formicinae
Tribe:	Camponotini
Genus:	Polyrhachis; Smith, F., 1857
Type species
	Formica bihamata, now Polyrhachis bihamata;
Subgenera
	Aulacomyrma Emery, 1921; Campomyrma Wheeler, W.M., 1911; Chariomyrma Forel, 1915; Cyrtomyrma Forel, 1915; Hagiomyrma Wheeler, W.M., 1911; Hedomyrma Forel, 1915; Hemioptica Roger, 1862; Hirtomyrma Kohout, 2010; Myrma Billberg, 1820; Myrmatopa Forel, 1915; Myrmhopla Forel, 1915; Myrmothrinax Forel, 1915; Polyrhachis Smith, F., 1857;
Diversity
	788 species; 1 fossil species; (Species Checklist, Species by Country) Polyrhachis bihamata Specimen Label
Synonyms
	Cephalomyrma Karavaiev, 1935; Dolichorhachis Mann, 1919; Evelyna Donisthorpe, 1937; Florencea Donisthorpe, 1937; Irenea Donisthorpe, 1938; Johnia Karavaiev, 1927; Morleyidris Donisthorpe, 1944;

Evolutionary Relationships

	Gigantiops (1 species)

	Santschiella (1 species)

Myrmoteras
(41 species)

Camponotini

Colobopsis
(117 species)

Opisthopsis
(20 species)

Dinomyrmex
(2 species)

Polyrhachis
(788 species)

Camponotus
(1,502 species)

	Calomyrmex (14 species)

	Echinopla (39 species)

Based on Ward et al. 2016.

Rudy Kohout has spent more than 2 decades revising members of this diverse genus. His ongoing publications focus on sets of species placed in species groups. These groups are organized by subgenera. Dorow (1995) presented the first contemporary reorganization of what had previously slowly developed into a messy tangle of poorly organized groups and forms. Kohout's revisions have altered some of Dorow's groupings. This has come about as particular species and groups have been more carefully assessed. There no longer exists any published overview detailing how all the species groups are organized under their respective subgenera. Antwiki does present some of these updated group revisions and species keys (species groups are presented on their respective subgenera for many groups; see the subgenera listed in the taxobox on the right side of this page). A phylogenetic analysis, using molecular sampling, has recently examined the relationships within and between existing groups (Mezger & Moreau 2015, see below). Not all of the groupings are supported by this analysis. Most of the modern taxonomic revisions have been clear in stating that the current groupings are logical constructs largely based on similarities in morphology and are not phylogenetic hypotheses. Both the species groups and subgenera are important considering the current taxonomic state of the genus as a whole.

Photo Gallery

Polyrhachis sp. infected by Ophiocordyceps buquetii, in Ghana. (Photo by João P. M. Araújo)

Identification

Bolton (1973) - Worker. Monomorphic, medium to large (4.4 to 14.1 mm) ants belonging to the formicine tribe Camponotini. Antennae 12-segmented, the scapes inserted some distance behind the posterior clypeal margin (usually a distance greater than the basal width of the scape). Palp formula 6,4; mandibles usually with five, rarely with four teeth. Eyes well developed. Pronotum armed with a pair of spines, teeth or tubercles in all species of the Ethiopian region, the propodeum usually armed with two spines, teeth or tubercles, or a pair of ridges, rarely with only a single transverse ridge or completely unarmed. Promesonotal suture usually present (absent from khepra ), the development of the metanotal groove variable. Mesoscutellum very rarely present. In the single species in which the mesoscutellum occurs on the dorsum of the alitrunk, it is not separated from the scutum by a deep impression. Margination of the alitrunk variable, often present and complete but showing all stages through to a fully immarginate condition. Petiole usually with four but occasionally with two or six spines or teeth of variable configuration. Gaster large, globose, the first tergite extensive, usually forming at least half of the dorsal surface. The anterior face of the first gastral tergite is often truncated or concave. Acidopore not borne upon a conical projection of the hypopygium, usually concealed by the pygidium when not in use. Queen. As worker but with the alitrunk massively developed and with a corresponding reduction in armament and margination. The petiolar spines tend to be reduced and are usually smaller than those of the associated worker. Ocelli are present and wing venation is of the usual camponotine form. Male. Very poorly known, in most cases indistinguishable from the males of Camponotus.

Keys including this Genus

Key to Australian Genera of Formicinae

Keys to Species in this Genus

See the nomenclature section below for links to more Polyhrachis keys.

Distribution

Distribution and Richness based on AntMaps

Fossils

Fossils are known from: Varvara Formation, Apomarma, Messara Basin, Crete, Greece (Messinian, Late Miocene).

Biology

Bolton (1973) - The nesting habits of the genus as a whole have been discussed by Hung (1967) who sums up by saying that four types may be recognised, as follows:

1. Arboreal: carton and silk nests amongst leaves and twigs.

2. Lignicolous: nests in the cavities of plants.

3. Terrestrial: nests on the ground under any object.

4. Subterranean: nests in the soil, without cover.

Robson & Kohout (2007) - Based on a review of 197 of the approximately 500 described species of Polyrhachis, the majority of species within a particular subgenus demonstrate a consistent nesting type but a few species can be highly variable, demonstrating both subterranean and arboreal habits. The inclusion of larval silk in the nests is correlated almost entirely with arboreal nesting, but the presence of spider silk in the nests of at least four species suggests caution when inferring silk origin. Pupal cocoons are present in all but subgenera Cyrtomyrma and Myrmatopa.

Africa

Bolton (1973) - All four nesting types (see above) are found in the Ethiopian regional fauna. Obviously, the first on the list is more or less restricted to forest species whilst the third and fourth are most commonly found in savannah forms. The second type listed above is rather a broad category and as far as the Ethiopian region is concerned includes such diverse nest sites as those of Polyrhachis decemdentata in rotten or termite-mined tree branches and those of Polyrhachis cubaensis inside stem galls. It would probably also hold Polyrhachis otleti which nests in rot holes or crevices in tree trunks and covers the entrance with a mesh of silk and vegetable fibres.

The distribution of the species may be divided roughly into forest and savannah forms although some may penetrate the edges of one from the other. The species Polyrhachis viscosa and Polyrhachis schistacea may be considered as typical of the savannah forms, spreading throughout the continent; the former even occurs on the coastal plains of West Africa. Nests are constructed in the earth and the ants are fast-moving, ascending grasses and bushes to forage. The forest species are typified by Polyrhachis militaris and Polyrhachis decemdentata, arboreal retiring forms foraging singly upon the trees and with a marked tendency to release their grip and fall into the undergrowth if disturbed.

Association with Other Organisms

Spider Mimics

A Polyrhachis-mimicking spider from Trivandrum, India. Photo by Kalesh Sadasivan.
A spider mimic of a member of the subgenus Cyrtomyrma from Cairns, Australia. Photo by Steve Shattuck.

Diptera

This species is a prey for the Microdon fly Microdon waterhousei (a predator) (Quevillon, 2018).

Hymenoptera

This species is a host for the eucharitid wasp Rhipipalloidea sp. (a parasitoid) (Quevillon, 2018) (multiple encounter modes; direct transmission; transmission outside nest).
This species is a host for the eucharitid wasp Rhipipalloidea sp. (a parasite) (Universal Chalcidoidea Database) (primary host).
This species is a host for the eucharitid wasp Stilbula arenae (a parasitoid) (Quevillon, 2018) (multiple encounter modes; direct transmission; transmission outside nest).
This species is a host for the eucharitid wasp Stilbula arenae (a parasite) (Universal Chalcidoidea Database) (primary host; Polyrhachis sp., Cyrtomyrma sp.).

Fungi

Unknown species of Polyrhachis are hosts for the fungi Ophiocordyceps irangiensis, Ophiocordyceps ootakii, Ophiocordyceps myrmecophila and Ophiocordyceps satoi (Araujo et al., 2018; Shrestha et al., 2017).
This species is a host for the fungus Aspergillus flavus (a parasitoid) (Quevillon, 2018) (encounter mode primary; direct transmission; transmission within nest).
This species is a host for the fungus Ophiocordyceps irangiensis (a parasitoid) (Quevillon, 2018) (encounter mode primary; direct transmission; transmission outside nest).
This species is a host for the fungus Ophiocordyceps myrmecophila (a parasitoid) (Quevillon, 2018) (encounter mode primary; direct transmission; transmission outside nest).
This species is a host for the fungus Ophiocordyceps ootaki (a parasitoid) (Quevillon, 2018) (encounter mode primary; direct transmission; transmission outside nest).
This species is a host for the fungus Ophiocordyceps satoi (a parasitoid) (Quevillon, 2018) (encounter mode primary; direct transmission; transmission outside nest).
This species is a host for the fungus Ophiocordyceps sp. (GH 41) (a parasitoid) (Quevillon, 2018) (encounter mode primary; direct transmission; transmission outside nest).
This species is a host for the fungus Ophiocordyceps unilateralis (a parasitoid) (Quevillon, 2018) (encounter mode primary; direct transmission; transmission outside nest).

All Associate Records for Genus

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Taxon	Relationship	Associate Type	Associate Taxon	Associate Relationship	Locality	Source	Notes
Polyrhachis	host	eucharitid wasp	Rhipipalloidea sp.	parasite		Universal Chalcidoidea Database	primary host
Polyrhachis	host	eucharitid wasp	Rhipipalloidea sp.	parasitoid		Quevillon, 2018	multiple encounter modes; direct transmission; transmission outside nest
Polyrhachis	host	eucharitid wasp	Stilbula arenae	parasite		Universal Chalcidoidea Database	primary host; ''Polyrhachis'' sp., ''Cyrtomyrma'' sp.
Polyrhachis	host	eucharitid wasp	Stilbula arenae	parasitoid		Quevillon, 2018	multiple encounter modes; direct transmission; transmission outside nest
Polyrhachis	host	fungus	Aspergillus flavus	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission within nest
Polyrhachis	host	fungus	Ophiocordyceps irangiensis	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis	host	fungus	Ophiocordyceps irangiensis	pathogen		Shrestha et al., 2017
Polyrhachis	host	fungus	Ophiocordyceps myrmecophila	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis	host	fungus	Ophiocordyceps myrmecophila	pathogen		Shrestha et al., 2017
Polyrhachis	host	fungus	Ophiocordyceps ootaki	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis	host	fungus	Ophiocordyceps ootakii	pathogen		Araujo et al., 2018
Polyrhachis	host	fungus	Ophiocordyceps satoi	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis	host	fungus	Ophiocordyceps satoi	pathogen		Araujo et al., 2018
Polyrhachis	host	fungus	Ophiocordyceps sp. (GH 41)	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis	host	fungus	Ophiocordyceps unilateralis	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis	prey	''Microdon'' fly	Microdon waterhousei	predator		Quevillon, 2018
Polyrhachis abdominalis	host	fungus	Ophiocordyceps irangiensis	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis abdominalis	host	fungus	Ophiocordyceps myrmecophila	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis armata	host	fungus	Ophiocordyceps formicarum	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis armata	host	fungus	Ophiocordyceps irangiensis	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis armata	host	fungus	Ophiocordyceps myrmecophila	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis armata	host	fungus	Ophiocordyceps unilateralis	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis armata	host	fungus	Ophiocordyceps unilateralis	pathogen		Shrestha et al., 2017
Polyrhachis bellicosa	host	cricket	Myrmecophilus polyrhachi	myrmecophile	Gombak, Malaysia
Polyrhachis bellicosa	host	phorid fly	Megaselia holosericei	parasite		Brown et al., 2015	injured
Polyrhachis bellicosa	host	phorid fly	Megaselia sp.	parasite		Brown et al., 2015	injured
Polyrhachis bellicosa	host	phorid fly	Megaselia sp.	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis bicolor	host	fungus	Ophiocordyceps formicarum	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis bicolor	host	fungus	Ophiocordyceps irangiensis	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis bicolor	host	fungus	Ophiocordyceps myrmecophila	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis bicolor	host	fungus	Ophiocordyceps unilateralis	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis bihamata	host	fungus	Ophiocordyceps irangiensis	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis bihamata	host	fungus	Ophiocordyceps myrmecophila	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis calypso	host	fungus	Ophiocordyceps formicarum	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis debilis	host	fungus	Ophiocordyceps unilateralis	pathogen	Taiwan	Lin et al., 2020
Polyrhachis decemdentata	host	fungus	Akanthomyces gracilis	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis decemdentata	host	fungus	Ophiocordyceps unilateralis	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis decemdentata	host	fungus	Ophiocordyceps unilateralis	pathogen		Shrestha et al., 2017
Polyrhachis delecta	host	nematode	Mermithidae (unspec.)	parasite	Australia (N. Queensland)	Downes, 2017; Laciny, 2021
Polyrhachis dives	host	eucharitid wasp	Stilbula polyrachicida	parasitoid		Quevillon, 2018	multiple encounter modes; direct transmission; transmission outside nest
Polyrhachis dives	host	eucharitid wasp	Stilbula polyrhachicida	parasite		Universal Chalcidoidea Database	primary host
Polyrhachis dives	host	eucharitid wasp	Stilbuloida doddi	parasitoid		Quevillon, 2018	multiple encounter modes; direct transmission; transmission outside nest
Polyrhachis dives	host	fungus	Ophiocordyceps unilateralis	pathogen	Taiwan	Lin et al., 2020
Polyrhachis exercita	prey	tiger beetle	Cicindela flavomaculata	predator	Western Ghats, India	Sinu et al., 2006
Polyrhachis exercita	prey	tiger beetle	Cicindela whithilli	predator	Western Ghats, India	Sinu et al., 2006
Polyrhachis femorata	host	eucharitid wasp	Rhipipalloidea mira	parasite		Universal Chalcidoidea Database	primary host
Polyrhachis fissa	host	fungus	Ophiocordyceps unilateralis	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis fissa	host	fungus	Ophiocordyceps unilateralis	pathogen		Shrestha et al., 2017
Polyrhachis furcata	host	fungus	Ophiocordyceps formicarum	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis furcata	host	fungus	Ophiocordyceps irangiensis	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis furcata	host	fungus	Ophiocordyceps myrmecophila	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis furcata	host	fungus	Ophiocordyceps unilateralis	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis furcata	host	fungus	Ophiocordyceps unilateralis	pathogen		Shrestha et al., 2017
Polyrhachis halidayi	host	fungus	Ophiocordyceps formicarum	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis halidayi	host	fungus	Ophiocordyceps irangiensis	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis halidayi	host	fungus	Ophiocordyceps myrmecophila	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis halidayi	host	fungus	Ophiocordyceps unilateralis	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis hauxwelli	host	fungus	Ophiocordyceps formicarum	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis hauxwelli	host	fungus	Ophiocordyceps unilateralis	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis hauxwelli	prey	tiger beetle	Cicindela flavomaculata	predator	Western Ghats, India	Sinu et al., 2006
Polyrhachis hauxwelli	prey	tiger beetle	Cicindela whithilli	predator	Western Ghats, India	Sinu et al., 2006
Polyrhachis hippomanes	host	fungus	Ophiocordyceps formicarum	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis hippomanes	host	fungus	Ophiocordyceps irangiensis	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis hippomanes	host	fungus	Ophiocordyceps unilateralis	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis hippomanes	host	fungus	Ophiocordyceps unilateralis	pathogen		Shrestha et al., 2017
Polyrhachis illaudata	host	fungus	Ophiocordyceps formicarum	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis illaudata	host	fungus	Ophiocordyceps irangiensis	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis illaudata	host	fungus	Ophiocordyceps myrmecophila	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis illaudata	host	fungus	Ophiocordyceps unilateralis	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis illaudata	host	fungus	Ophiocordyceps unilateralis	pathogen	Taiwan	Lin et al., 2020
Polyrhachis illaudata	host	milichiid fly	Milichia sp.	myrmecophile	Malaysia	Yusah & Fayle, 2014; Milichiidae online
Polyrhachis illaudata	host	phorid fly	Megaselia holosericei	parasite		Brown et al., 2015	injured
Polyrhachis laboriosa	host	fungus	Ophiocordyceps unilateralis	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis laboriosa	host	fungus	Ophiocordyceps unilateralis	pathogen		Shrestha et al., 2017
Polyrhachis lama	inquiline	ant	Diacamma sp.
Polyrhachis lamellidens	host	''Microdon'' fly	Microdon piperi	predator	Oregon, Montana, Washington (type)	Knab, 1917
Polyrhachis lamellidens	host	fungus	Ophiocordyceps unilateralis	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis lamellidens	host	fungus	Ophiocordyceps unilateralis var. clavata	pathogen		Shrestha et al., 2017
Polyrhachis lamellidens	prey	''Microdon'' fly	Microdon katsurai	predator		Quevillon, 2018
Polyrhachis lamellidens	temporary parasite	ant	Camponotus japonicus	host		Kohriba, 1963
Polyrhachis lamellidens	temporary parasite	ant	Camponotus kiusiuensis	host		Sakai, 1990	Needs confirmation
Polyrhachis lamellidens	temporary parasite	ant	Camponotus obscuripes	host		Sakai, 1990
Polyrhachis latharis	host	fungus	Ophiocordyceps unilateralis	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis latharis	host	fungus	Ophiocordyceps unilateralis	pathogen		Shrestha et al., 2017
Polyrhachis latispina	host	fungus	Ophiocordyceps unilateralis	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis latispina	host	fungus	Ophiocordyceps unilateralis	pathogen		Shrestha et al., 2017
Polyrhachis latona	host	fungus	Ophiocordyceps unilateralis	pathogen	Taiwan	Lin et al., 2020
Polyrhachis militaris	host	fungus	Akanthomyces gracilis	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis militaris	host	fungus	Ophiocordyceps unilateralis	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis militaris	host	fungus	Ophiocordyceps unilateralis	pathogen		Shrestha et al., 2017
Polyrhachis monista	host	fungus	Akanthomyces gracilis	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis monista	host	fungus	Ophiocordyceps unilateralis	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis monista	host	fungus	Ophiocordyceps unilateralis	pathogen		Shrestha et al., 2017
Polyrhachis monteithi	host	nematode	Mermithidae (unspec.)	parasite	Australia (N. Queensland)	Downes, 2017; Laciny, 2021
Polyrhachis proxima	host	fungus	Ophiocordyceps formicarum	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis proxima	host	fungus	Ophiocordyceps irangiensis	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis proxima	host	fungus	Ophiocordyceps myrmecophila	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis proxima	host	fungus	Ophiocordyceps unilateralis	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis proxima	host	fungus	Ophiocordyceps unilateralis	pathogen		Shrestha et al., 2017
Polyrhachis rastellata	host	fungus	Ophiocordyceps formicarum	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis rastellata	host	fungus	Ophiocordyceps unilateralis	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis revoili	host	fungus	Ophiocordyceps unilateralis	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis revoili	host	fungus	Ophiocordyceps unilateralis	pathogen		Shrestha et al., 2017
Polyrhachis robsoni	host	fungus	Ophiocordyceps myrmecophila	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis robsoni	host	fungus	Ophiocordyceps naomipierceae	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis robsoni	host	fungus	Ophiocordyceps naomipierceae	pathogen		Araujo et al., 2018	identity of ant species uncertain
Polyrhachis robsoni	host	fungus	Ophiocordyceps pseudolloydii	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis rufofemorata	host	fungus	Ophiocordyceps unilateralis	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis rufofemorata	host	fungus	Ophiocordyceps unilateralis	pathogen		Shrestha et al., 2017
Polyrhachis schellerichae	mutualist	mealybug	Kermicus wroughtoni	trophobiont		Schellerich-Kaaden et al. 1997
Polyrhachis sulcata	host	fungus	Ophiocordyceps unilateralis	parasitoid		Quevillon, 2018	encounter mode primary; direct transmission; transmission outside nest
Polyrhachis sulcata	host	fungus	Ophiocordyceps unilateralis	pathogen		Shrestha et al., 2017
Polyrhachis vigilans	host	fungus	Ophiocordyceps unilateralis	pathogen	Taiwan	Lin et al., 2020
Polyrhachis wolfi	host	fungus	Ophiocordyceps unilateralis	pathogen	Taiwan	Lin et al., 2020

Flight Period

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Taxon	Month	Source	Notes
Polyrhachis lamellidens	Sep • Oct • Nov

Life History Traits

Mean colony size: 60-878096 (Greer et al., 2021)
Compound colony type: temperary parasite; xenobiosis? (Greer et al., 2021)
Nest site: hypogaeic; arboreal (Greer et al., 2021)
Diet class: omnivore (Greer et al., 2021)
Foraging stratum: subterranean/leaf litter; arboreal (Greer et al., 2021)

Castes

Phylogeny

(Mezger & Moreau 2015) Spiny ants (Polyrhachis Smith) are a hyper-diverse genus of ants distributed throughout the Palaeotropics and the temperate zones of Australia. To investigate the evolution and biogeographic history of the group, we reconstructed their phylogeny and biogeography using molecular data from 209 taxa and seven genes. Our molecular data support the monophyly of Polyrhachis at the generic level and several of the 13 recognized subgenera, but not all are recovered as monophyletic. We found that Campomyrma Wheeler consists of two distinct clades that follow biogeographic affinities, that the boundaries of Hagiomyrma Wheeler are unclear depending on the analysis, that Myrma Billberg might be treated as one or two clades, and that Myrmhopla Forel is not monophyletic, as previously proposed. Our biogeographic ancestral range analyses suggest that the evolution of Polyrhachis originated in South-East Asia, with an age of the modern crown-group Polyrhachis of 58 Ma. Spiny ants dispersed out of South-East Asia to Australia several times, but only once to mainland Africa around 26 Ma.

Morphology

Worker Morphology

• Antennal segment count: 12 • Antennal club: absent-gradual • Palp formula: 6,4 • Total dental count: 5-6 • Spur formula: 1 simple-pectinate, 1 simple-pectinate; 0, 0 • Eyes: >100 ommatidia • Scrobes: absent • Pronotal Spines: dentiform; present • Mesonotal Spines: absent • Propodeal Spines: dentiform; present • Petiolar Spines: dentiform; present • Caste: none or weak • Sting: absent • Metaplural Gland: absent • Cocoon: polymorphic

Karyotype

Species Uncertain

Polyrhachis sp.(ANIC-1): 2n = 42 (Australia) (Imai et al., 1977).
Polyrhachis sp.1: n = 21 (Malaysia) (Goni et al., 1982).
Polyrhachis sp.2: n = 21 (Malaysia) (Goni et al., 1982).
Polyrhachis sp.3: 2n = 20 (Malaysia) (Goni et al., 1982).

All Karyotype Records for Genus

Explore Data: All, Drilldown

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Taxon	Haploid	Diploid	Karyotype	Locality	Source	Notes
Polyrhachis		20		Malaysia	Goni et al., 1982
Polyrhachis		42		Australia	Imai et al., 1977
Polyrhachis	21			Malaysia	Goni et al., 1982
Polyrhachis ammon	21	42		Australia	Imai et al., 1977
Polyrhachis dives	21		1M+8SM+1ST+3A+8T	Taiwan	Hung et al., 1972
Polyrhachis gribodoi		48		Indonesia	Imai et al., 1985
Polyrhachis hector	21	42		Malaysia	Imai et al., 1983
Polyrhachis hippomanes	20	40		Japan	Imai, 1969
Polyrhachis illaudata	14	28		Indonesia	Imai et al., 1985
Polyrhachis illaudata	18			Malaysia	Imai et al., 1983
Polyrhachis lacteipennis		42	6M+36A	India	Imai et al., 1984	as ''Polyrhachis simplex''
Polyrhachis lamellidens		42		Japan	Imai, 1969
Polyrhachis rastellata	21	42	8M+34SM	Malaysia	Crozier, 1970b; Imai et al., 1983

Nomenclature

The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.

POLYRHACHIS [Formicinae: Camponotini]
- Polyrhachis Smith, F. 1857a: 58. Type-species: Formica bihamata, by original designation.
- [Polyrhachis Shuckard, in Swainson & Shuckard, 1840: 172. Nomen nudum.]
- Polyrhachis subgenus of Myrma: Wheeler, W.M. 1911c: 860; Wheeler, W.M. 1911f: 170.
- [Myrma subgenus of Polyrhachis: Forel, 1915b: 106; Forel, 1917: 251; Wheeler, W.M. 1922a: 702, 993; Emery, 1925b: 198 (see note under Myrma).]
- Subgenera of Polyrhachis (alphabetical order with synonyms indicated): nominal plus Aulacomyrma (= Johnia), Campomyrma, Chariomyrma, Cyrtomyrma, Hagiomyrma, Hedomyrma (= Dolichorhachis, = Morleyidris), Hemioptica, Hirtomyrma, Myrma (= Anoplomyrma, = Hoplomyrmus, = Pseudocyrtomyrma), Myrmatopa (= Irenea), Myrmhopla (= Cephalomyrma, = Florencea), Myrmothrinax (= Evelyna).
- [All subgenera were given as provisional junior synonyms of Polyrhachis by Brown, 1973b: 178-184. The list was repeated in Hölldobler & Wilson, 1990: 19 with all subgenera listed as junior synonyms. They reverted to subgeneric status in Bolton, 1994: 50; see under individual entries. The entry of Chariomyrma, Hagiomyrma and Hedomyrma under the synonymy of Polyrhachis by Taylor & Brown, D.R. 1985: 131, is not considered as confirmation as the three subgenera all range outside the Austral Region.]
Polyrachis Arnold, 1924: 741, incorrect subsequent spelling.

Dorow (1995) provides the latest revision of the species into subgenera and species-groups. These hierarchical arranged names are not supported by any strong evidence that these groups between the genus and species level represent monophyletic units. Regardless, much of the framework for these names has been in place for some time and they do serve as a welcome convenience for organizing the complex diversity of species. Rudy Kohout has been revising species by geographic areas and within specific subgenera and species-groups for more than two decades. Kohout's ongoing taxonomic work has largely followed the arrangement of Dorow (1995) with some modifications becoming necessary as more species have been described.

Aulacomyrma - key to Polyrhachis (Aulacomyrma) species

Campomyrma

The gravis species-group and a key to species.
The micans species-group and a key to species.
The xiphias species-group and a key to species.

Chariomyrma

Cyrtomyrma - key to Australian Cyrtomyrma species

Hagiomyrma - key to Polyrhachis Hagiomyrma group species

Hedomyrma

Hemioptica - species key

Myrma

Key to the subgenus Polyrhachis workers (includes lamellidens and bihamata species-groups)

References

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