Workers, soldiers, and gynes - morphometric characterization and description of the female castes of Camponotus singularis (Smith, 1858) (Hymenoptera, Formicidae)

Abstract

Species of Camponotus Mayr, 1861 show a high variation of worker caste numbers, from a monomorphic worker caste to strong polymorphism along a continuous range of worker sizes or true worker dimorphism. Camponotus singularis (Smith, 1858) is used as a model for a Camponotus species with two very distinct worker castes (minors and majors) which are chiefly defined by morphometric data. We investigated shifts in proportions of C. singularis female castes in order to identify major allometric patters useful for characterizing caste differences in this species as well as in other Camponotini. We describe the main morphological traits which are characteristic for the respective morphs. The major worker, or "soldier", shows many characteristics which deviate from the minor worker, but also from the alate gyne. Its traits are assumingly modified for its function in nest defence. Morphometric data clearly set Bornean specimens of Camponotus singularis (described as var. rufomaculatus Donisthorpe, 1941) apart from specimens with other proveniences, suggesting that this island population is a distinct species.