A preliminary study of the usefulness of morphometric tools for splitting the Monomorium antarcticum (Smith) complex (Hymenoptera: Formicidae), New Zealand's most common native ants

Abstract

The Monomorium antarcticum complex includes the most common and ubiquitous of New Zealand ants.This group displays a high degree of variability, causing considerable confusion in its taxonomy. Using classical methods, previous authors have divided this complex into five or more species. However it is possible that most of the characters used are intraspecific rather than interspecific, and that there might be only one or two viable species in the complex. It is therefore important to examine new approaches that have the potential to address M. antarcticum systematics more effectively. This study explores the possibility of employing multivariate morphometric tools towards a classification of the M. antarcticum complex.Thirty-two M. antarcticum (sensu lato) colonies were randomly collected between April 28 and May 29, 2003, in the Wellington region. Principal component analysis and discriminant analysis were applied to examine five morphometric variables of the workers.The results of these statistical analyses show the existence of three distinct morphospecies in samples collected, indicating multivariate morphometric analyses as useful tools for discriminating M. antarcticum s.l. species. The next step will be to use these tools to examine the M. antarcticum complex from throughout New Zealand and combine them with molecular analyses.