by Joe A. MacGown, last updated 26 November 2013
Cyphomyrmex rimosus, frontal view of the head of a worker (photo by Joe A. MacGown)
Cyphomyrmex rimosus, side view of a worker (photo by Joe A. Macgown)
Cyphomyrmex rimosus, side view of a queen (photo by Joe A. MacGown)
Cyphomyrmex rimosus is a small dull brown to blackish brown attine ant with deep antennal scrobes, enlarged frontal lobes that obscure the lateral margins of the face (see photo of head above), no propodeal spines, an apedunculate petiole, and tubercles on the mesosoma. The species is native to the Neotropics, but has established introduced populations in the southern United States and the Galapagos islands. It is not considered a pest species in its native or introduced range.
Taxonomic History (provided by Barry Bolton, 2013)
This species is similar to C. minutus, which is apparently native to Florida and smaller in size. According to Snelling and Longino (1992), the head width of C. minutus is less than 0.56 mm and hairs in center of first gastral tergite are closely appressed and usually separated by more than their own lengths, whereas in C. rimosus, the head width is greater than 0.62 mm and hairs on first gastral tergite are not completely appressed and separated by less than their own lengths (Snelling and Longino 1992). I examined specimens of both species at the collection in Gainesville, FL and had a hard time telling them apart, but I did not have an ocular micrometer to measure head widths.
Biology and Economic Importance
The colony size of C. rimosus is typically small, with usually less than 100 workers, although colonies with over 300 workers have been observed (Murakami & Higashi, 1997). Ccolonies are typically monogynous, but may be polygynous (Murakami and Higashi, 1997; Snelling and Longino, 1992).
Similar to other Attines, Cyphomyrmex cultivates subterranean fungus gardens, growing the fungus on a substrate of vegetable matter, insect frass, and dead insects. These fungus gardens are composed of yeasts in the unicellular phase. Fungal gardens of most other attine species are in the multicellular, mycelial phase (Mehdiabadi & Schultz, 2010). Cyphomyrmex rimosus supplements its diet with nectar and sap of plants (Murakami & Higashi, 1997). The queens have been reported to practice monandry and semi-claustral nest founding (Mehdiabadi & Schultz, 2010; Tschinkel, 1987). Nests are often simple, shallow, impermanent structures under rocks, logs, dry cow manure, or any other surface. This species is very common in open habitats such as pastures and also in open woodlands such as longleaf pine forests.
This species is not considered to be a pest, but in areas of high abundance, they could invade homes in search of sugary food substances.
Introduced Range (non US). Galapagos: Isabella, Santa Cruz (Snelling and Longino, 1992).
Introduced Range in the United States: Alabama, Florida, Georgia, Mississippi, and Texas (MEM). Smith (1979) also reported this species from Arizona and California, but Snelling and Longino (1992) did not include it as occurring in those states in their more recent publication. Thus, these records are likely incorrect.
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