European Journal of Entomology (Jan 2020)
Phenotypic diversity in red wood ants (Hymenoptera: Formicidae): Is kinship involved?
Abstract
Phenotypic diversity depends on genotype diversity, but the degree of genotype-by-environment interaction is species-specific. Red wood ants (Formica s. str) are keystone species in boreal forests and very variable phenotypically. These variations are used for species identification and proposed as ecological indicators of anthropogenic disturbances. However, their origin is unknown. Here we aimed to provide a preliminary answer to this question and outline the direction for future research. We determined the interrelation between nest mate worker relatedness (kinship) and the diversity of colour morphs, degree of melanisation and size of the red wood ant, Formica rufa. In Finnish populations of this species polyandry, which involves multiple mating by queens is the principal determinant of the relatedness between workers. We hypothesised, that if phenotypic diversity is a result of genetic diversity, then polyandrous colonies should produce more phenotypically diverse workers. A total of 336 individuals belonging to 20 colonies were used for this study. We collected ants from coniferous and broadleaf forests in Finland, fixed them in 96% alcohol, then digitally photographed, genotyped and analysed the phenotypic variation. The average colony nest mate worker relatedness was used as an estimate of the level of polyandry (more than one if r < 0.6). Our results revealed no associations between the diversity of the phenotypic traits measured and worker kinship in F. rufa. As a further step to reveal the degree of genotype-by-environment interaction in determining the colour traits of the red wood ant we suggest more sophisticated genetic studies indicating the heritability of phenotypic traits between patrilinies and testing of environmental factors such as temperature, humidity, UV-radiation, food and pollution.
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