Comparative nesting ecology and behavior of Camponotus rufipes and C. renggeri (Formicidae: Formicinae) in two physiognomies of Cerrado savanna

The genus Camponotus is the second most diverse in species in the Neotropics. Camponotus rufipes and C. renggeri (subgenus Myrmothrix) are very similar morphologically and there is uncertainty about their taxonomic status. The nesting ecology of both species was studied in a reserve of Cerrado savanna in southeast Brazil in two vegetation physiognomies: “cerradão” (closed woodland) and cerrado sensu stricto (dense scrub of shrubs and trees).  We investigated nest structure and distribution in C. rufipes and C. renggeri, and evaluated how nests persist through time. Camponotus rufipes presented five categories of nests: dry straw, dry straw associated with shrub, beneath the ground, in erect dead trunk, or in fallen dead trunk. Camponotus renggeri had three categories of nests: beneath the ground, in erect dead trunk, or in fallen dead trunk. All C. rufipes nests were found in cerrado sensu stricto, whereas C. renggeri was observed in cerradão (78%) and cerrado sensu stricto (22%). Nest persistence over 9 months was higher in C. rufipes compared to C. renggeri. The distribution pattern of C. rufipes nests was aggregated whereas of C. renggeri nests was random, suggesting that these species face different environmental pressures at each vegetation physiognomy. Colonies of C. rufipes were generally more populous than those of C. renggeri, and in both species we found more than one dealated queen, suggesting a polygynous habit. The ecological and behavioral data show notable differences between these two species, which contributes for the taxonomic delimitation between C. rufipes and C. renggeri (FAPESP, CNPq).