Ant nest architecture is shaped by local adaptation and plastic response to temperature

Jessica Purcell,Madison Sankovitz

doi:10.1038/s41598-021-02491-w

Abstract

Social insects are among the most abundant arthropods in terrestrial ecosystems, where they provide ecosystem services. The effect of subterranean activity of ants on soil is well-studied, yet little is known about nest architecture due to the difficulty of observing belowground patterns. Furthermore, many species’ ranges span environmental gradients, and their nest architecture is likely shaped by the climatic and landscape features of their specific habitats. We investigated the effects of two temperature treatments on the shape and size of nests built by Formica podzolica ants collected from high and low elevations in the Colorado Rocky Mountains in a full factorial experiment. Ants nested in experimental chambers with soil surface temperatures matching the local temperatures of sample sites. We observed a plastic response of nest architecture to conditions experienced during excavation; workers experiencing a high temperature excavated deeper nests than those experiencing a cooler temperature. Further, we found evidence of local adaptation to temperature, with a significant interaction effect of natal elevation and temperature treatment on nest size and complexity. Specifically, workers from high elevation sites built larger nests with more tunnels when placed in the cool surface temperature treatment, and workers from low elevation sites exhibited the opposite pattern. Our results suggest that subterranean ant nest architecture is shaped by a combination of plastic and locally adapted building behaviors; we suggest that the flexibility of this ‘extended phenotype’ likely contributes to the widespread success of ants.

Highlights

In addition to providing environmental stability, ant nest architecture shapes and, in turn, is shaped by collective behavior and provides an opportunity to study individual- and colony-level behaviors in a shared, dynamic environment[8]
Physiology and individual-level behavioral variation can have colony-level effects reflected in nest architecture; for example, a building pheromone added by individual workers to the nest material has been shown to be a critical factor that controls the growth and form of nest architecture[19]
Most previous studies on subterranean nest architecture have been conducted in a single habitat, yet many ant species ranges span distinct habitats and climates, some of which are rapidly changing with climate and other anthropogenic disturbances[20]

Summary

Introduction

In addition to providing environmental stability, ant nest architecture shapes and, in turn, is shaped by collective behavior and provides an opportunity to study individual- and colony-level behaviors in a shared, dynamic environment[8]. Global warming has stimulated worldwide studies aiming to assess or predict the impact of rising environmental temperatures on o rganisms[21,22,23]. Many of these studies have focused on thermal tolerances of terrestrial ectotherms[24,25,26] because they represent the vast majority of terrestrial biodiversity[27] and are especially likely to be vulnerable to climate warming due to the strong influence of environmental temperature on their physiological and behavioral functions[28]. We measured nest size (depth and area) and complexity (number of tunnels) daily during week-long trials

Methods

Results

Discussion

Conclusion