Pheidole morrisi

Wilson, E. O., 2003, Pheidole in the New World. A dominant, hyperdiverse ant genus., Cambridge, MA: Harvard University Press : 325-326

Pheidole morrisi Forel

Pheidole morrisii Forel 1886b: xlvi. Syn.: Pheidole morrisi var. impexa Wheeler 1908h: 461, n. syn.; Pheidole morrisii var. vanceae Forel 1901j: 351, synonymy by Creighton 1950a: 183.

Types Mus. Hist. Nat. Geneve.

Etymology Eponymous.

Diagnosis A member of the fallax group easily distinguished by the following traits.

Major: yellow; antennal scape approaches occipital comer within 2X its own width; propodeal spines reduced to denticles; rugoreticulum lacking on head; pilosity dense and very long, many hairs longer than Eye Length; postpetiole from above elliptical, with subangulate lateral borders.

Minor: yellow; propodeal spines reduced to right or obtuse angles; occiput slightly narrowed, with thin nuchal crest. The types of impexa differ from typical eastern morrisi in having two-layered gastral pilosity, flattened scape at the bend, and a more narrowly tapered petiolar node in the major. I have treated the form as a western geographic variant, i.e., from Oklahoma and Texas, but it may prove to be a distinct species.

Measurements (mm) Major (Selden, New York): HW 1.26, HL 1.26, SL 0.88, EL 0.24, PW 0.62. Minor (Selden, New York): HW 0.60, HL 0.82, SL 0.90, EL 0.16, PW 0.40. Color Major: concolorous yellow.

Minor: yellow, with head and mesosoma a slightly darker shade than rest of body and appendages.

Range Long Island, New York south to South Florida, and west to Illinois, Missouri, Oklahoma, and Texas.

biology This is a locally abundant species that prefers pure sand, where it often builds crater mounds or nests at the base of grass clumps. According to Naves (1985), colonies are large and live primarily as scavengers, although they also occasionally collect seeds.

Workers have been observed foraging as much as 8 meters or more from the nests. Minors forage singly at night, with majors often emerging from the nest to help carry back food. Nest-founding queens build vertical passageways to a claustral chamber 20-30 cm below the surface, and use the excavated soil of the chamber to plug the passageway. Naves observed rapid growth in incipient colonies: the first minors emerge in 30 days, the first majors in 50 days, with colonies growing to several hundred workers in 8 months. In New York winged queens are present in nests during July, and in Florida as early as May (Stefan Cover, unpublished records). Cover (personal communication) has also noted that morrisi "shows a fascinating variation in life history over its large geographic range. Populations in the northeast (Long Island and New Jersey pine barrens) have pleometrotic colony founding, and exhibit primary polygyny -one of the very few documented cases in the ants. Colonies are almost always monodomous. In the southeastern United States, morrisi is haplometrotic and monogynous but colonies are often polydomous."

figure Upper: major. Lower: minor. NEW YORK: Selden, Suffolk Co. (Type locality: Vineland, New Jersey.) Scale bars = 1 mm.