Should we lump or split? The case of the Pheidole megacephala species group along a strong environmental gradient in the Soutpansberg Mountains in the Limpopo Province, South Africa?

Abstract

Pheidole megacephala (Fabricius, 1793) is an ant species of the family Formicidae that includes at least ten subspecies. It is one of the three species that are found across the Soutpansberg Mountain. The mountain is characterised by a strong environmental gradient and raises the question whether the taxon includes cryptic species. The study was conducted along a north-south altitudinal transect. We hypothesized that P. megacephala found in this transect is one species. DNA barcoding was used to determine if there are any cryptic species within this species group. DNA extraction was conducted on the whole ant using the Qiagen extraction kit after which the DNA was viewed on a 1.75% agarose gel. The polymerase chain reaction was used for DNA amplification, followed by sequencing and phylogenetic analysis where the Neighbour joining, Maximum likelihood and Maximum. Sequence extraction and amplification was only successful for two specimens. Phylogenetic analysis suggests that the two specimens belong to different clades, and that P. megacephala species group along the mountain consist of cryptic species. These conclusions are however confounded by the small sample size and the possibility of misidentifications based on morphology