Big-headed Ants

Pheidole

Classification

Phylum: Arthropoda
Subphylum: Hexapoda
Class: Insecta
Order: Hymenoptera
Superfamily: Formicoidea
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Pheidole

Pronunciation

How to pronounce Pheidole: /faɪˈdoʊli/

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Images

Pheidole deserticola by the Smithsonian. Used under a CC0 license.

Pheidole caffra abyssinica by the Smithsonian. Used under a CC0 license.

Pheidole (Electropheidole) colaensis by the Smithsonian. Used under a CC0 license.

Pheidole hyatti var. ecitonodora by the Smithsonian. Used under a CC0 license.

Summary

Pheidole, also known as big-headed ants, is a diverse genus of ants characterized by pronounced worker caste dimorphism and significant ecological roles as seed harvesters and predators. With over 1,000 species, they are one of the largest ant genera worldwide, displaying a complex social structure.

Physical Characteristics

Minors range from 1.5-4 mm; majors range from 2-5 mm; supermajors of P. rhea can reach up to 8 mm. Major workers have disproportionately large heads compared to their body size.

Identification Tips

Pheidole species can be nearly indistinguishable from small Aphaenogaster workers, but Aphaenogaster never have big-headed majors and are usually larger in size than most Pheidole minors.

Habitat

Cosmopolitan, particularly diverse in tropical regions; found from the northern US to Argentina.

Distribution

Widely distributed, with high diversity in the tropics; abundant and diverse in New World regions, particularly the desert Southwest and Southeast.

Diet

Some species are seed harvesters, while many are generalist predators and scavengers.

Life Cycle

Colonies typically contain one or several queens, as well as alates - virgin winged females and males. Most species display worker caste dimorphism with minor and major workers.

Predators

Many Pheidole species fall prey to parasitoid phorid flies, which lay eggs on major workers.

Ecosystem Role

Pheidole species are ecologically important seed consumers and play a role in regulating populations of other insects as scavenger predators.

Evolution

Evolved in the Americas and spread worldwide; abiotic and biotic factors contributed to their ecological dominance.

Similar Taxa

Misconceptions

The major workers may appear fierce but are often shy and likely to flee from danger.