Odontomachus chelifer

De la Mora et al. (2016) found this species nesting in logs found in coffee farms and forests in the Soconusco region of Chiapas, Mexico. A small percentage of pupae were found to be parasitized by eucharitid wasps.

Distribution based on Regional Taxon Lists
Neotropical Region: Argentina, Bolivia, Brazil, Colombia, Costa Rica, French Guiana, Guatemala, Guyana, Honduras, Mexico, Panama, Paraguay, Peru, Suriname, Venezuela.

Biology
Rosumek (2017) assessed trophic resource use and period of activity within the ant community in a southern Brazil Atlantic forest. For this species: Odontomachus chelifer and Pachycondyla striata are two widespread species that differ radically in morphology but are similar in many aspects. It is appropriate to discuss both together. They are one of the most conspicuous elements of the southern Atlantic forest ground fauna, due to their abundance, solitary foraging mode and large size. Several accounts show these species occupy a multitude of functional roles and have a broad trophic niche. Observation of nest entrances showed that 80-90% of the items carried by P. striata were arthropod parts, mostly termites and other ants, with the remainder consisting of plant material (Giannotti & Machado, 1991; Medeiros & Oliveira, 2009). Through direct observation, Medeiros and Oliveira (2009) also showed that scavenging accounts for more than 80% of its foraging behavior. On the other hand, Fowler (1980) reported O. chelifer prefers certain termite species in the laboratory, and qualitatively stated that in the field prey consisted almost entirely of termites. In the Atlantic forest, all items carried to nests were arthropods, mainly termites, but other animal groups accounted for 60% of them (Raimundo et al., 2009). Scavenging was also cited in this study, although not quantified. Both O. chelifer and P. striata were recorded on experimental carcasses predating the larvae and pupae of necrophagous insects (Paula et al., 2016).

Other important items used by the two species are seeds with elaiosomes and other fallen diaspores rich in proteins and lipids, frequently collected from the ground in the Atlantic forest (Pizo & Oliveira, 2000; Passos & Oliveira, 2002, 2004). Field records on use of liquid sugars are scant and qualitative. Odontomachus chelifer was not observed using extra-floral nectaries by Raimundo et al. (2009), while there is one record for P. striata (in Cerrado, the Brazilian savannah – Byk & Del-Claro, 2010).

The results presented here are mostly consistent with this broader picture. Both species more frequently foraged upon dead insects, sucrose and large prey. In fact, they were the only two species consistently recorded on crickets. The low frequency in termite baits is unexpected and probably represents a methodological artifact. These large solitary foragers were observed quickly collecting termites (even glued ones) and leaving the baits in a few minutes, contrary to ants of smaller species that recruited to them. In cricket baits, however, the two species spent more time trying to carry out the tied cricket or dismembering it. Smaller ants frequently took advantage of this to grab the remains or lick spilled hemolymph. This largely contributed to the richness found in this bait and could happen in nature, whenever predators kill prey too large to carry them out at once.

Besides predation, scavenging was a common behavior, and P. striata in particular would prioritize it whenever possible, in accordance with what was observed by Medeiros and Oliveira (2009). This could be result of their morphology, because the triangular mandibles may be more suited to chop large carcasses than the trap-jaws of O. chelifer. In addition, it could be an effect of competition. The two species were never found at the same bait, and co-occurred in just 10 of the 62 points where they were recorded. The two were previously reported to avoid each other, but, when agonistic interactions occur, P. striata usually is the winner, and can steal the food or kill (and eat) O. chelifer (Medeiros & Oliveira, 2009; Raimundo et al., 2009). Thus, P. striata could displace O. chelifer and maintain control of a valuable resource such as dead arthropods through tandem recruitment (Medeiros & Oliveira, 2009; Silva-Melo & Giannotti, 2012), while cooperative foraging behavior was not observed in O. chelifer (Raimundo et al., 2009). Effectively, the average numbers of workers per bait was smaller for the latter species (O. chelifer = 1.4 ± 0.9; P. striata = 2.5 ± 2; Mann-Whitney, z = -2.27, p = 0.02).

Both species used sucrose frequently and rarely foraged on melezitose (anolog for honeydew). They were never observed foraging on trees or low vegetation in this study, which fits previous accounts (Fowler, 1980; Medeiros & Oliveira 2009), so it is unlikely that they commonly use nectar as food source. This behavior also should limit honeydew use by them.

Past results have shown that these species show a preference for day (P. striata) or night foraging (O. chelifer). No preference in their time of foraging was found in this study.

Nomenclature

 *  chelifer. Formica chelifera Latreille, 1802c: 188, pl. 8, fig. 51 (w.) SOUTH AMERICA (no locality given). Forel, 1909a: 252 (q.m.); Wheeler, G.C. & Wheeler, J. 1952c: 651 (l.). Combination in Odontomachus: Latreille, 1809: 128. Senior synonym of emacerata: Brown, 1976a: 103; of leptocephalus: Emery, 1911d: 114; of theresiae: Forel, 1899c: 19; Brown, 1976a: 103.
 * leptocephalus. Odontomachus chelifer var. leptocephalus Emery, 1890b: 45, pl. 5, fig. 2 (w.) BRAZIL. Junior synonym of chelifer: Emery, 1911d: 114.
 * theresiae. Odontomachus haematodes r. theresiae Forel, 1895a: 41 (w.) MEXICO. Emery, 1901a: 53 (m.). Subspecies of chelifer: Emery, 1901a: 53; Forel, 1912c: 28; Kempf, 1972a: 170. Junior synonym of chelifer: Forel, 1899c: 19; Brown, 1976a: 103.
 * emacerata. Odontomachus chelifer var. emacerata Santschi, 1922d: 243 (w.) BRAZIL. Junior synonym of chelifer: Brown, 1976a: 103.