Pheidole indica Mayr

Sarnat, Eli M., Fischer, Georg, Guenard, Benoit & Economo, Evan P., 2015, Introduced Pheidole of the world: taxonomy, biology and distribution, ZooKeys 543, pp. 1-109 : 30-31

Taxon classification Animalia Hymenoptera Formicidae

Pheidole indica Mayr Figs 73, 78, 88f

Pheidole indica . Pheidole indica Mayr 1879: 679 (s.w.q.) INDIA, Calcutta [NHMW, paralectotype s.w., examined]. Forel 1902b: 199 (m.); Imai et al. 1984: 6 (k.). Lectotype designated Eguchi 2004b: 199 (s.).

Pheidole Note. Material of the unavailable name Pheidole javana r. jubilans var. formosae Forel 1912: 60 referred to Pheidole indica : Eguchi 2004b: 199.

Pheidole striativentris . Pheidole striativentris Mayr 1879: 678 (s.) INDIA: Calcutta. Forel 1902b: 195 (w.q.). Junior synonym of indica : Eguchi 2004b: 199.

Pheidole teneriffana . Pheidole teneriffana Forel 1893b: 465 (s.w.) SPAIN, Canary Is. (s.) Laguna, Tenerife (M. Medina); (q.) Las Palmas, Canarías (Cabrera y Díaz). [Also described as new by Forel 1894a: 160.] Queen described: Santschi 1908: 521. Male described: Gómez and Espadaler 2006: 229. n. syn.

Pheidole voeltzkowii . Pheidole voeltzkowii Forel 1894b: 227 (s.w.m.) MADAGASCAR. Queen described: Forel 1897: 207. Junior synonym of teneriffana : Fischer and Fisher 2013: 340. n. syn.

Pheidole himalayana . Pheidole indica r. himalayana Forel 1902b: 185 (s.), 199 (w.) INDIA. [Also described as new by Forel 1902a: 546.] Raised to species: Bingham 1903: 265. Subspecies of indica : Emery 1921: 91; Menozzi 1939: 298; Pisarski 1967: 385. Junior synonym of indica : Eguchi 2004b: 198.

Pheidole rotschana . Pheidole indica r. rotschana Forel 1902b: 185 (s.), 199 (w.m.) INDIA: Poona, Orissa, Trevandrum and Thana. Lectotype designated Eguchi 2004b: 199 (s.) INDIA: Poona. Imai et al. 1984: 6 (k.). [Also described as new by Forel 1902a: 546.] Raised to species: Bingham 1903: 264. Subspecies of indica : Forel 1909b: 394; Forel 1911a: 222. Junior synonym of indica : Eguchi 2004b: 199.

Pheidole taina . Pheidole teneriffana subsp. taina Aguayo 1932: 219 (s.) CUBA, Holguín, viii.1930 (C.G. Aguayo). Junior synonym of teneriffana : Wilson 2003: 640. See also: Baroni Urbani 1968: 438; Snelling, R.R. 1992: 121. n. syn.

Diagnosis among introduced Pheidole .

Light to dark reddish brown. MajorHW 1.32-1.74, HL 1.31-1.76, SL 0.73-0.91, CI 94-117, SI 47-62 (n=22). Head subquadrate (Fig. 7); rugoreticulate on posterolateral lobes and laterad of frontal carinae (Fig. 13a), but frons dominated by long, well-organized and parallel longitudinal rugae (Fig. 13b). Frontal carinae extend 3/4 distance of head before terminating (Fig. 15). Antennal scrobes indistinct to moderately impressed, but frontal carinae always forming a border capable of accepting the antennal scape (Fig. 13c). Hypostoma with weakly produced median tooth and submedian teeth. Promesonotum in profile with two convexities (Fig. 5), the large anterior dome in addition to a distinct mound or prominence on the posterior slope. Postpetiole not swollen relative to petiole (Fig. 3). MinorHW 0.50-0.65, HL 0.60-0.74, SL 0.64-0.81, CI 72-90, SI 120-149 (n=20). Head predominantly glossy (Fig. 36), lacking punctation and or rugae above eye level. Posterior head margin weakly convex to flat in full-face view (Fig. 45). Antennal scapes long (e.g. Fig. 39), but not surpassing the posterior head margin by more than 2 × eye length. Promesonotum in profile with two convexities, the large anterior dome (Fig. 43a) in addition to a distinct prominence on the posterior slope (Fig. 43b). Promesonotal prominence relatively convex (Fig. 50a). Metanotal depression relatively shallow (Fig. 50b). Petiole and postpetiole glossy to very weakly sculptured laterally (Fig. 48). Postpetiole not swollen relative to petiole (Fig. 3).

Identification, taxonomy and systematics.

Pheidole indica is a medium to large reddish brown species with relatively long limbs. It belongs to the Pheidole fervens clade along with its Australasian congeners Pheidole cariniceps , Pheidole fervens , Pheidole hospes , Pheidole impressiceps , and Pheidole oceanica ( Economo et al. 2015, unpublished data). The major and minor workers are distinguished from those of Pheidole megacephala by the lack of a swollen postpetiole (Fig. 3). The majors are also easily separated from those of Pheidole megacephala by the strongly sculptured head (Fig. 13). The minors can be confused with those of Pheidole megacephala because both have glossy heads. However, the minors of Pheidole fervens can be separated from those of Pheidole megacephala by the relatively longer antennal scapes (Fig. 39 vs. Fig. 40) and the presence of a promesonotal prominence (Fig. 43 vs. Fig. 42). Pheidole indica is broadly sympatric with Pheidole noda and Pheidole fervens . It is easily separated from the former by the lack of a swollen postpetiole (Fig. 3 vs. Fig. 2). Separation from Pheidole fervens is quite difficult, and readers are referred to corresponding section under that species for distinguishing characters. Readers are referred to Eguchi (2004b; 2008) for characters used to separate Pheidole indica and Pheidole fervens from their Asian congeners.

Pheidole indica was originally described from India. Eguchi (2004b) synonymized several other Asian congeners under Pheidole indica and discussed taxonomic differences used to distinguish it from Pheidole fervens and other morphologically similar species. We synonymize Pheidole teneriffana under Pheidole indica based on morphological analysis of the type specimens and genetic analysis of previously determined specimens (unpublished data). Forel, in his original description of Pheidole teneriffana , noted the similarity between it and Pheidole striativentris [= indica ].

The biogeographical origin of Pheidole teneriffana has been a minor mystery of the past century, as revealed by the recent review of the species by Wetterer (2011). There appeared to be general consensus that Pheidole teneriffana was native to at least some portion of North Africa, Arabia, the Middle East or the Mediterranean. Santschi (1918), suggested the upper Nile area (South Sudan). Wilson (2003) suggested North Africa and potentially the Canary Islands. Collingwood et al. (2004) suggested it was native throughout northern Africa and observed it to be, "spreading over a wide front in the Middle East, Arabia and the Mediterranean countries." Wetterer (2011) found the distribution of Pheidole teneriffana enigmatic, "Curiously, most Old World records of Pheidole teneriffana are subtropical, but all New World records are tropical, except one from California … If Pheidole teneriffana is truly native across North Africa, it is remarkable how few records I found from any North African country other than Egypt."

Biology.

In Asia Pheidole indica is known to nest in soil or under stones in open and dry habitats ( Eguchi 2004b). It is among the most widespread Pheidole species in Asia. In the Caribbean Wetterer (2011) found Pheidole indica [as Pheidole teneriffana ] almost exclusively on beaches and at highly disturbed urban sites, particularly in waterfront areas. In northern Africa, Santschi (1908) noted the tramp-like distribution of what he treated as Pheidole teneriffana , "This species, described by Forel on samples from the Canary Islands, was sent to me from Cairo. I discovered it most recently in Sousse [Tunisia], in the park, near the port. As it does not exist in the interior, I think it is one species cosmopolitan tendencies. It nests in the ground and under stones." Santschi (1934) later reported the species from Alexandria, Egypt, and noted that Pheidole teneriffana was rarely reported far from seaports. Collingwood et al. (1997) reported that in the United Arab Emirates, Pheidole indica [as Pheidole teneriffana ] was populous in irrigated gardens and along the coast where it appeared to be spreading rapidly, possibly to the detriment of local species. The species has also been reported from urban areas of the Balearic Islands where it is common in the gardens and trees and on sidewalks near the harbor ( Gómez and Espadaler 2006). Fischer and Fisher (2013) reported Pheidole indica [as Pheidole teneriffana ] from the Malagasy region. It was collected on the Comoros, Mauritius, the Seychelles, and from coastal towns in Madagascar, usually from under stones, ground nests, or foraging on the ground or lower vegetation in urban or garden habitats at elevations below 300 m. It was also found on Mayotte in native littoral and secondary forest below 10 m.

Perhaps the most detailed study of Pheidole indica in the New World comes from the account of Martínez (1992) who reported a vigorous population, represented by a putatively single polydomous colony spanning several hectares, that was discovered in Long Beach, California in 1989. Martínez (1992) reportedly observed 23 inseminated queens from a single colony that was changing nest sites (although no details are given for how he knew the queens were inseminated). He described the colony nests as low mounds on the soil, along curbs or sidewalks, at the edges of lawns, in cracks in pavement, and at the bases of trees. New colonies were started by budding. Workers foraged night and day unless temperature exceeded 26 °C, taking seeds and scavenging dead or dying insects. They were observed feeding on sweet or greasy foods, but were not seen tending aphids. Martínez (1992) observed the species attacking native ants, including Pogonomyrmex californicus (Buckley). More remarkably, he reportedly observed Pheidole indica destroying colonies and taking over nest sites of Linepithema humile . Despite the purported success of these battles, Pheidole indica must have lost the larger war against Linepithema humile , as the eventual extirpation of the Californian population was attributed to the Argentine ant ( Gulmahamad 1999).

Distribution.

We treat all occurrence records from the regions of Indomalaya west of the Korean Peninsula as native. The Korean and Japanese populations are considered introduced ( Choi and Bang 1993; Choi et al. 1993a; Choi et al. 1993b; Terayama 1992), and additional portions of the range in Asia might also have resulted from anthropogenic transport. Pheidole indica has been introduced to scattered localities across the globe, although the vast majority of these records were attributed to its junior synonym, Pheidole teneriffana . Introduced populations have been reported from the Mediterranean, northern Africa, the Malagasy region, Western Australia, Peru, the Caribbean, and southern California.

Risk statement.

Pheidole indica is not considered to be a major pest to either agriculture or native ecosystems. Although the species is tolerant of disturbed and urban areas, we found no reports of it infesting structures. Few studies have measured the effect of Pheidole indica on ecosystem health, but we predict that it could negatively impact native arthropods. The species is continuing to spread across the globe and further studies are required to test its ecological and agricultural impact outside its native range.