Comparison of foraging tool use in two species of myrmicine ants (Hymenoptera: Formicidae)

Gábor Módra,István Maák,Gábor Lőrinczi,Ádám Lőrincz

doi:10.1007/s00040-021-00838-0

Gábor Módra, István Maák + Show 2 more

Open Access

https://doi.org/10.1007/s00040-021-00838-0

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Abstract

Many ant species are known to exhibit foraging tool use, during which ants place various debris items (e.g., pieces of soil, leaves, pine needles, etc.) into liquid food, and then they carry the food-soaked tools back to the nest. In the present study, we compared the tool-using behavior in captive colonies of two closely related myrmicine ants with different feeding preferences: Aphaenogaster subterranea, an omnivorous species, and Messor structor, a mainly granivorous seed-harvester species. We supplied foraging ants with honey-water baits and six types of objects they could use as tools: sand grains, small soil grains, large soil grains, pine needles, leaves, and sponges. We found that the workers of A. subterranea both dropped more tools into honey-water baits and retrieved more of these tools than the workers of M. structor. While A. subterranea preferred smaller tools over larger ones, tool preferences for M. structor did not differ significantly from random. In addition, tool dropping was significantly faster in A. subterranea, and both the dropping and retrieving of tools began significantly earlier than in M. structor. For Aphaenogaster species that regularly utilize and compete for liquid food sources, the ability to efficiently transport liquid food via tools may be more important than it is for seed-harvester ants. Dropping tools into liquids, however, may still be useful for seed-harvester species as a means to supplement diet with liquid food during periods of seed shortage and also to serve as a means of getting rid of unwanted liquids close to the nest.

Highlights

In the last few decades, the study of tool use has been a general interest among researchers of animal behavior
It has been known that the members of the genera Aphaenogaster and Messor can use tools to transport liquid food, no previous study has compared the tool-using behavior of these two taxa
Despite the variation present among the colonies of both species, our results support the hypothesis that the omnivorous A. subterranea shows many differences in the nature of its tool-using behavior when compared to M. structor, a mainly granivorous species

Summary

Introduction

In the last few decades, the study of tool use has been a general interest among researchers of animal behavior. Even though there is an increasing number of publications in the topic, we know little about the origin of this behavior, especially in insects. One example of the many types of insect tool use is the foraging behavior of some myrmicine ants. During this behavior, ants place various debris items (e.g., pieces of soil, leaves, pine needles, etc.) into liquid food, and they carry the food-soaked tools back to the nest (e.g., Fellers and Fellers 1976; Banschbach et al 2006). Environment or other organisms in the environment” (St. Amant and Horton 2008)

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