External immunity in ant societies: sociality and colony size do not predict investment in antimicrobials

Social insects live in dense groups with a high probability of disease transmission and have therefore faced strong pressures to develop defences against pathogens. For this reason, social insects have been hypothesized to invest in antimicrobial secretions as a mechanism of external immunity to pre...

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Main Authors: Clint A. Penick, Omar Halawani, Bria Pearson, Stephanie Mathews, Margarita M. López-Uribe, Robert R. Dunn, Adrian A. Smith
Format: Article
Language:English
Published: The Royal Society 2018-01-01
Series:Royal Society Open Science
Subjects:
Online Access:https://royalsocietypublishing.org/doi/pdf/10.1098/rsos.171332
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author Clint A. Penick
Omar Halawani
Bria Pearson
Stephanie Mathews
Margarita M. López-Uribe
Robert R. Dunn
Adrian A. Smith
author_facet Clint A. Penick
Omar Halawani
Bria Pearson
Stephanie Mathews
Margarita M. López-Uribe
Robert R. Dunn
Adrian A. Smith
author_sort Clint A. Penick
collection DOAJ
description Social insects live in dense groups with a high probability of disease transmission and have therefore faced strong pressures to develop defences against pathogens. For this reason, social insects have been hypothesized to invest in antimicrobial secretions as a mechanism of external immunity to prevent the spread of disease. However, empirical studies linking the evolution of sociality with increased investment in antimicrobials have been relatively few. Here we quantify the strength of antimicrobial secretions among 20 ant species that cover a broad spectrum of ant diversity and colony sizes. We extracted external compounds from ant workers to test whether they inhibited the growth of the bacterium Staphylococcus epidermidis. Because all ant species are highly social, we predicted that all species would exhibit some antimicrobial activity and that species that form the largest colonies would exhibit the strongest antimicrobial response. Our comparative approach revealed that strong surface antimicrobials are common to particular ant clades, but 40% of species exhibited no antimicrobial activity at all. We also found no correlation between antimicrobial activity and colony size. Rather than relying on antimicrobial secretions as external immunity to control pathogen spread, many ant species have probably developed alternative strategies to defend against disease pressure.
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spelling doaj.art-126743198c73438b8c598907d4a355bd2022-12-21T21:09:52ZengThe Royal SocietyRoyal Society Open Science2054-57032018-01-015210.1098/rsos.171332171332External immunity in ant societies: sociality and colony size do not predict investment in antimicrobialsClint A. PenickOmar HalawaniBria PearsonStephanie MathewsMargarita M. López-UribeRobert R. DunnAdrian A. SmithSocial insects live in dense groups with a high probability of disease transmission and have therefore faced strong pressures to develop defences against pathogens. For this reason, social insects have been hypothesized to invest in antimicrobial secretions as a mechanism of external immunity to prevent the spread of disease. However, empirical studies linking the evolution of sociality with increased investment in antimicrobials have been relatively few. Here we quantify the strength of antimicrobial secretions among 20 ant species that cover a broad spectrum of ant diversity and colony sizes. We extracted external compounds from ant workers to test whether they inhibited the growth of the bacterium Staphylococcus epidermidis. Because all ant species are highly social, we predicted that all species would exhibit some antimicrobial activity and that species that form the largest colonies would exhibit the strongest antimicrobial response. Our comparative approach revealed that strong surface antimicrobials are common to particular ant clades, but 40% of species exhibited no antimicrobial activity at all. We also found no correlation between antimicrobial activity and colony size. Rather than relying on antimicrobial secretions as external immunity to control pathogen spread, many ant species have probably developed alternative strategies to defend against disease pressure.https://royalsocietypublishing.org/doi/pdf/10.1098/rsos.171332antimicrobial secretionsantibioticssocial immunitysocial insectsantsentomopathogens
spellingShingle Clint A. Penick
Omar Halawani
Bria Pearson
Stephanie Mathews
Margarita M. López-Uribe
Robert R. Dunn
Adrian A. Smith
External immunity in ant societies: sociality and colony size do not predict investment in antimicrobials
Royal Society Open Science
antimicrobial secretions
antibiotics
social immunity
social insects
ants
entomopathogens
title External immunity in ant societies: sociality and colony size do not predict investment in antimicrobials
title_full External immunity in ant societies: sociality and colony size do not predict investment in antimicrobials
title_fullStr External immunity in ant societies: sociality and colony size do not predict investment in antimicrobials
title_full_unstemmed External immunity in ant societies: sociality and colony size do not predict investment in antimicrobials
title_short External immunity in ant societies: sociality and colony size do not predict investment in antimicrobials
title_sort external immunity in ant societies sociality and colony size do not predict investment in antimicrobials
topic antimicrobial secretions
antibiotics
social immunity
social insects
ants
entomopathogens
url https://royalsocietypublishing.org/doi/pdf/10.1098/rsos.171332
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