Body Size Differences between Foraging and Intranidal Workers of the Monomorphic Ant Lasius niger.

Mateusz Okrutniak,Irena M Grześ,Filip Turza,Bartosz Rom

doi:10.3390/insects11070433

Mateusz Okrutniak, Irena M Grześ + Show 2 more

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https://doi.org/10.3390/insects11070433

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Abstract

The association between the division of labour and worker body size of ants is typical for species that maintain physical castes. Some studies showed that this phenomenon can be also observed in the absence of distinct morphological subcastes among workers. However, the general and consistent patterns in the size-based division of labour in monomorphic ants are largely unidentified. In this study, we performed a field experiment to investigate the link between worker body size and the division of labour of the ant Lasius niger (Linnaeus, 1758), which displays limited worker size variation. We demonstrated that the body size of workers exploring tuna baits is slightly but significantly smaller than the size of workers located in the upper parts of the nest. Comparing the present results with existing studies, large workers do not seem to be dedicated to work outside the nest. We suggest that monomorphic workers of certain body sizes are flexible in the choice of task they perform, and food type may be the important determinant of this choice.

Highlights

Division of labour is one of the most fundamental features of social insect colony behavior
Describing the proximate factors determining the association between body size and the work organization of social insects may lead to a better understanding of the evolution of their phenotypic diversity
The two-way ANOVA analysis showed that both factors—“colony” and “worker class”—as well generally significantly larger than workers attracted to the tuna (Figure 2)

Summary

Introduction

Division of labour is one of the most fundamental features of social insect colony behavior. A number of studies confirmed that division of labour is related to the worker body size of many social insects, such as bees [4], bumblebees [5,6,7], eusocial wasps [8], termites [9] and especially ants [10,11,12]. Describing the proximate factors determining the association between body size and the work organization of social insects may lead to a better understanding of the evolution of their phenotypic diversity. The relationship between body size and task allocation of ant workers is mostly recognized from studies of species with discrete worker subcastes (polymorphic ants) [13,14]. The less radical form of size-related division of labour is the diversification into minor and major workers. In many dimorphic species of the genus Pheidole, major workers showed a trend toward specialization for defence and/or food storage while minor workers perform virtually all tasks, including nest maintenance, brood care, and foraging [19,20]

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