Philidris nagasau

Philidris nagasau
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Dolichoderinae
Tribe:	Leptomyrmecini
Genus:	Philidris
Species:	P. nagasau
Binomial name
	Philidris nagasau; (Mann, 1921) Specimen Labels
Synonyms
	Philidris nagasau agnatus Mann, 1921; Philidris nagasau alticola Mann, 1921;

Philidris nagasau is polydomous. It cultivates and manages large Squamellaria colonies by collecting and planting the plants’ seeds under tree bark and fertilising its crop from the seedling stage onward. The ants feed on sugar- and amino-acid-rich floral food rewards produced by mature Squamellaria plants (Chomicki and Renner 2016; Chomicki et al. 2016, Chomicki and Renner 2019, Chomicki et al. 2019). The ants obligately use the domatia of this plant for their nests.

At a Glance

• Ant garden

Photo Gallery

The farming symbiosis between Fijian Squamellaria and Philidris nagasau ants. (a) P. nagasau worker dispersing a Squamellaria seed; (b) Squamellaria “nursery” where a sunken site has been planted with seeds and two seedlings are emerging (arrowheads show holes in the bark where a worker emerges, bark removal revealed that many seeds were present, guarded by P. nagasau workers); (c) P. nagasau worker (arrowhead) visiting the tiny domatium of a Squamellaria seedling to fertilize it; (d) longitudinal section through a large Squamellaria wilsonii, revealing two types of inner wall structures: the warted walls (left inset) where ants defecate and place detritus and the smooth walls (right inset) where ants rear their brood; (e) Squamellaria “farm” with dozens of individuals, here S. major and S. thekii, overlooking a bay, in Taveuni island, Fiji and; (f) food rewards (nectary in old flowers) in Squamellaria wilsonii, Taveuni island, Fiji. Photographs: Guillaume Chomicki (Chomicki et al., 2019, Fig. 1).
Squamellaria major, a threatened ant‐farmed epiphyte endemic to Taveuni island, Fiji. A virtual section through the domatium shows the inner cavity channels. A longitudinal section is shown in the bottom right corner. Illustration: Chris J. Thorogood (Chomicki et al., 2019, Fig. 2).

Identification

Distribution

Latitudinal Distribution Pattern

Latitudinal Range: -16.583° to -19.0775°.


North Temperate	North Subtropical	Tropical	South Subtropical	South Temperate

Source: AntMaps

Distribution based on Regional Taxon Lists

Indo-Australian Region: Fiji (type locality).

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

Chomicki and Renner (2019) studied nutrient uptake in ephipytic plants in the genus Squamellaria. Seeds of this plant are placed under bark by P. nagasau, and the ants obligately use the ephiphyte, which forms a domatia, for their nests. This study showed that nutrient uptake was greatly enhanced by the ants, putatively through the ants defecating on absorptive warts found on the inside walls of the domatia. The warts are thought to be analogous to root hairs in their capacity and function.

Ant Gardens

This species is known to form ant gardens (i.e., they are able to initiate ant gardens or are restricted to ant gardens) (Campbell et al., 2022; Chomicki & Renner, 2016).

Castes

Nomenclature

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

nagasau. Iridomyrmex nagasau Mann, 1921: 470, fig. 27 (w.) FIJI IS. Combination in Philidris: Shattuck, 1992a: 18. Senior synonym of agnatus, alticola: Sarnat & Economo, 2012: 36.
agnatus. Iridomyrmex nagasau subsp. agnatus Mann, 1921: 472 (w.) FIJI IS. Combination in Philidris: Shattuck, 1992a: 18. Junior synonym of nagasau: Sarnat & Economo, 2012: 36.
alticola. Iridomyrmex nagasau subsp. alticola Mann, 1921: 472 (w.) FIJI IS. Combination in Philidris: Shattuck, 1992a: 18. Junior synonym of nagasau: Sarnat & Economo, 2012: 36.

Description

References

Campbell, L.C.E., Kiers, E.T., Chomicki, G. 2022. The evolution of plant cultivation by ants. Trends in Plant Science (doi:10.1016/j.tplants.2022.09.005).
Chomicki, G., Renner, S.S. 2016. Obligate plant farming by a specialized ant. Nat. Plants 2: 1–4.
Chomicki, G., Renner, S.S. 2019. Farming by ants remodels nutrient uptake in epiphytes. New Phytologist 223: 2011-2023 (doi:10.1111/nph.15855 10.1111/nph.15855).
Chomicki, G., Thorogood, C.J., Naikatini, A., Renner, S.S. 2019. Squamellaria: Plants domesticated by ants. PLANTS, PEOPLE, PLANET 1(4), 302–305 (doi:10.1002/ppp3.10072).
Dejean, A., Naskrecki, P., Faucher, C., Azémar, F., Tindo, M., Manzi, S., Gryta, H. 2023. An Old World leaf‐cutting, fungus‐growing ant: A case of convergent evolution. Ecology and Evolution 13: e9904 (doi:10.1002/ece3.9904).
Mann, W. M. 1921. The ants of the Fiji Islands. Bulletin of the Museum of Comparative Zoology 64: 401-499 (page 470, fig. 27 worker described)
Sarnat, E.M. & Economo, E.P. 2012. The ants of Fiji: 384 pp. UC Publications in Entomology, University of California Press.
Shattuck, S. O. 1992a. Review of the dolichoderine ant genus Iridomyrmex Mayr with descriptions of three new genera (Hymenoptera: Formicidae). J. Aust. Entomol. Soc. 31: 13-18 (page 18, Combination in Philidris)

References based on Global Ant Biodiversity Informatics

Dlussky G.M. 1994. Zoogeography of southwestern Oceania. Zhivotnoe naselenie ostrovov Iugo-Zapadnoi Okeanii ekologo-geograficheskie issledovanii 48-93.
Mann W. M. 1921. The ants of the Fiji Islands. Bulletin of the Museum of Comparative Zoology 64: 401-499.
Santschi F. 1928. Fourmis de îles Fidji. Revue Suisse de Zoologie 35: 67-74.
Sarnat Eli M. 2009. The Ants [Hymenoptera: Formicdiae] of Fiji: Systematics, Biogeography and Conservation of an Island Arc Fauna. 80-252
Shattuck S. O. 1994. Taxonomic catalog of the ant subfamilies Aneuretinae and Dolichoderinae (Hymenoptera: Formicidae). University of California Publications in Entomology 112: i-xix, 1-241.
Ward, Darren F. and James K. Wetterer. 2006. Checklist of the Ants of Fiji. Fiji Arthropods III 85: 23-47.
Wheeler W.M. 1935. Check list of the ants of Oceania. Occasional Papers of the Bernice Pauahi Bishop Museum 11(11):1-56.
Wheeler, William Morton.1935.Checklist of the Ants of Oceania.Occasional Papers 11(11): 3-56
Wilson E.O., and G.L. Hunt. 1967. Ant fauna of Futuna and Wallis islands, stepping stones to Polynesia. Pacific Insects 9(4): 563-584.
Wilson, Edward O. and George L. Hunt. 1967. Ant Fauna of Futuna and Wallis Islands, Stepping Stones To Polynesia. Pacific Insects. 9(4):563-584.
Wilson, Edward O. and Hunt, George L. Jr. 1967. Ant Fauna of Futuna and Wallis Islands, Stepping Stones to Polynesia. Pacific Insects. 9(4):563-584