Polyrhachis lama

Polyrhachis lama
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Formicinae
Tribe:	Camponotini
Genus:	Polyrhachis
Subgenus:	Hirtomyrma
Species:	P. lama
Binomial name
	Polyrhachis lama; Kohout, 1994 Specimen Label

Polyrhachis lama is an inquiline within the nests of Diacamma sp.

At a Glance

• Inquiline

Photo Gallery

Interaction of the parasitic Polyrhachis lama with its host Diacamma sp. from Java: During nest relocation a Polyrhachis worker (on right, colour-marked) follows in tandem one of its host species workers. Photo by U. Maschwitz.

Identification

A member of the P. veihmeyeri group.

The undeniable similarity between P. lama and the viehmeyeri-group prototype shows that both probably derived from the same ancestral stock. As noted earlier (Kohout, 1990:506), most of this group exhibit variability in the length of pronotal spines even within the same population. Their complete absence and replacement by forward produced carinae, as seen in lama, demonstrates their variability to the extreme and can be interpreted as a product of an independent development of the species in isolation (Kohout, 1994)

Distribution

The known distribution of the viehmeyeri-group is from the Moluccas through Papua New Guinea to the Solomon Islands and northern Australia (Kohout, 1990) but this could be underestimated. With the description of P. lama it appears that the group was in the past more widely distributed and, perhaps, lama is an isolated relic (Kohout, 1994).

Latitudinal Distribution Pattern

Latitudinal Range: -7.216666667° to -7.25°.


North Temperate	North Subtropical	Tropical	South Subtropical	South Temperate

Source: AntMaps

Distribution based on Regional Taxon Lists

Indo-Australian Region: Indonesia, Philippines.
Oriental Region: Tibet (type locality).
Palaearctic Region: China.

Distribution based on AntMaps

Distribution based on AntWeb specimens

Check data from AntWeb

Countries Occupied

Number of countries occupied by this species based on AntWiki Regional Taxon Lists. In general, fewer countries occupied indicates a narrower range, while more countries indicates a more widespread species.

Estimated Abundance

Relative abundance based on number of AntMaps records per species (this species within the purple bar). Fewer records (to the left) indicates a less abundant/encountered species while more records (to the right) indicates more abundant/encountered species.

Biology

The formicine ant Polyrhachis lama is a social parasite, exploiting its ponerine host ant species Diacamma sp. In most social parasitic associations, the parasitic species are closely related to their host species group, evolving directly from independent ancestors of the host species. However, in the Polyrhachis lama - Diacamma sp. association, the associated species belong to different ant subfamilies. Based on preliminary field surveys, the authors (Maschwitz et al. 2000) had presumed that P. lama might have given up its reproductive division of labour, i.e. workers would be able to produce males as well as workers and females parthenogenetically. In Maschwitz et al. 2004, this hypothesis was disproved: Polyrhachis lama workers cannot be fertilized and are only able to produce males. In the host-parasite association originating from nests possessing a P. lama queen, workers penetrate surrounding Diacamma sp. nests, carrying eggs or small larvae for rearing them within these satellite nests. The Polyrhachis-workers participate in prey items brought into the nest by the host workers. In this peculiar way, a single P. lama colony is able to exploit several Diacamma sp. colonies simultaneously. The strategy of P. lama reminds that of slave-making ants, though the latter have slave workers stolen as pupae from several neighbouring host colonies, whereas P. lama workers rear their queen‘s brood within neighbouring nests of the Diacamma host species.

The formicine ant Polyrhachis lama parasitises a phylogenetically distant host species, Diacamma sp. of the subfamily Ponerinae, but lives spatially mixed with the host colonies. Studies on integration and communication have indicated that P. lama shows a high degree of host integration. Witte et al. (2009) have studied the allocation of brood care behaviour, a central aspect of parasite integration, in mixed colonies of P. lama and Diacamma sp. Here, the parasite brood has a high degree of spatial integration, although it remains functionally separated regarding nutritive brood care. The observed spatial confinement of parasite brood is most likely due to an unusual method of chemical host integration. The parasite brood remains accepted in the Diacamma colonies only under the presence of adult parasites (P. lama workers). This suggests an active mechanism of chemical integration based on the acceptance allomones originating from P. lama workers.

Castes

Worker


.	Owned by Museum of Comparative Zoology.

Nomenclature

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

lama. Polyrhachis lama Kohout, 1994b: 137, fig. 1 (w.) TIBET. See also: Maschwitz, Dorow, Buschinger & Kalytta, 2000: 27.

Type Material

Holotype, worker, Xizang Zizhiqu (Tibet), China, 1938-39, Deutsche Tibet-Expedit. 1938-39 (E. Schafer), Senckenberg Deutsches Entomologisches Institut.
Paratype, 3 workers, 1 dealate queen, Xizang Zizhiqu (Tibet), China, 1938-39, Deutsche Tibet-Expedit. 1938-39 (E. Schafer), Senckenberg Deutsches Entomologisches Institut.
Paratype, 1 worker, Xizang Zizhiqu (Tibet), China, 1938-39, Deutsche Tibet-Expedit. 1938-39 (E. Schafer), Queensland Museum.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.

Description

Worker

(holotype cited first): TL c. 8.11, 8.32-8.72; HL 1.93, 1.87-2.03; HW 1.50, 1.47-1.56; CI 78, 75-79; SL 2.31, 2.21-2.40; SI 153, 150-155; PW 1.03, 0.97-1.06; MTL 2.97, 2.87-3.07 (5 measured).

Clypeus with deeply impressed basal margin; median longitudinal carina distinct anteriorly, indistinct posteriorly; median portion of anterior margin dentate laterally. Median ocellus rudimentary, lateral ocelli lacking. Pronotum unarmed; humeri produced into distinct, forward converging dorso-lateral carinae almost reaching the anterior pronotal margin. Promesonotal suture well impressed, metanotal groove rather ill defined. Propodeal spines well elevated, only slightly divergent. Dorsum of petiole convex, anterior and posterior margins obsolete; spines well elevated, divergent.

Clypeus, frontal and lateral areas of head, lateral branches of mesosoma and petiole moderately rugose; rugosity increasing dorsally and posteriorly with dorsa of head and mesosoma fairly coarsely vermiculate-rugose. Gastral dorsum opaque, striate-rugose, with sculpture progressively less distinct posteriorly.

Moderately long, yellowish and reddish bristlelike hairs fairly dense on all body surfaces, including appendages. Silvery pubescence, of distinctly shaggy appearance, rather dense, except on promesonotal dorsum where it is somewhat less abundant.

Generally dark reddish brown with head, mesosoma and petiole on dorsal aspect piceous. Mandibles, appendages and gaster a shade lighter.

Queen

TL c. 9.07; HL 1.96; 1.53; CI 78; SL 2.28; SI 149; PW 1.71; MTL 2.97 (1 measured).

Besides the usual characters identifying full sexuality, the general appearance of the available single female resembles the worker very closely. Pronotal humeri with short, ill-defined carinae. Propodeal and petiolar spines shorter, the former slightly, the latter rather more divergent. Sculpturation similar to that of worker, with density increasing from moderately rugose to fairly coarsely vermiculate-rugose, namely on the head and mesoscutum, contrasting sharply with that on mesoscutellum where it is distinctly less coarse with somewhat granular appearance. Bristle-like pilosity is definitely more dense than in the worker and abundant shaggy pubescence almost obscures the underlying sculpturation.

References

de la Mora, A., Sankovitz, M., Purcell, J. 2020. Ants (Hymenoptera: Formicidae) as host and intruder: recent advances and future directions in the study of exploitative strategies. Myrmecological News 30: 53-71 (doi:10.25849/MYRMECOL.NEWS_030:053).
Khachonpisitsak, S., Yamane, S., Sriwichai, P., Jaitrong, W. 2020. An updated checklist of the ants of Thailand (Hymenoptera, Formicidae). ZooKeys 998, 1–182 (doi:10.3897/zookeys.998.54902).
Kohout, R. J. 1994b. Polyrhachis lama, a new ant from the Tibetan plateau (Formicidae: Formicinae). Mem. Qld. Mus. 35: 137-138. (page 137, fig. 1 worker described)
Lenoir, A., P. D’Ettorre, P., Errard, C., Hefetz, A. 2001. Chemical ecology and social parasitism in ants. Annual Review of Entomology 46: 573–599.
Maschwitz, U., Go, C., Kaufmann, E., Buschinger, A. 2004. A unique strategy of host colony exploitation in a parasitic ant: workers of Polyrhachis lama rear their brood in neighbouring host nests. Naturwissenschaften 91: 40-43. doi:10.1007/s00114-003-0487-3
Maschwitz, U., Liefke, C., Buschinger, A. 2001: How host and parasite communicate: Signal analysis of tandem recruitment between ants of two subfamilies, Diacamma sp. (Ponerinae) and its inquiline Polyrhachis lama (Formicinae). Sociobiology 37, 65-77.
Maschwitz, U.; Dorow, W. H. O.; Buschinger, A.; Kalytta, G. 2000. Social parasitism involving ants of different subfamilies: Polyrhachis lama (Formicinae) an obligatory inquiline of Diacamma sp. (Ponerinae) in Java. Insectes Soc. 47: 27-35.
Schultner, E., Pulliainen, U. 2020. Brood recognition and discrimination in ants. Insectes Sociaux 67, 11–34 (doi:10.1007/s00040-019-00747-3).
Witte,V., Lehmann, L., Lustig, A., Maschwitz, U. 2009: Polyrhachis lama, a parasitic ant with an exceptional mode of social integration. Insectes Sociaux 56, 301-307.

References based on Global Ant Biodiversity Informatics

Kohout R.J. 1994. Polyrhachis lama, a new ant from the Tibetan plateau (Formicidae: Formicinae). Mem. Qld. Mus. 35: 137-138.
Maschwitz U., W. H. O. Dorow, A. Buschinger, and G. Kalytta. 2000. Social parasitism involving ants of different subfamilies: Polyrhachis lama (Formicinae) an obligatory inquiline of Diacamma sp. (Ponerinae) in Java. Insectes Soc. 47: 27-35.
Maschwitz, U., W.H.O. Dorow, A. Buschinger and G. Kalytta. 2000. Social parasitism involving ants of different subfamilies: Polyrhachis lama (Formicinae) an obligatory inquiline of Diacamma sp. (Ponerinae) in Java. Insectes Sociaux 47:27-35
Robson Simon Database Polyrhachis -05 Sept 2014
Witte, V., L. Lehmann, A. Lustig and U. Maschwitz. 2009. Polyrhachis lama, a parasitic ant with an exceptional mode of social integration. Insectes Sociaux 56(3):301-307.