Thermal sensitivity and seasonal change in the gut microbiome of a desert ant, Cephalotes rohweri. Issue 7 (31st May 2022)

• Record Type: Journal Article
• Authors: McMunn, Marshall S; Hudson, Asher I; Zemenick, Ash T; Egerer, Monika; Bennett, Lucas; Philpott, Stacy M; Vannette, Rachel L
• Is Part Of: FEMS microbiology ecology. Volume 98:Issue 7(2022)
• Publication Date: 2022-05-31
• Subjects: ants (Hymenoptera: Formicidae) -- bacteria -- climate change -- microbiome -- seasonality -- temperature; Microbial ecology -- Periodicals; Microbiology -- Periodicals; 579.17
• DOI: 10.1093/femsec/fiac062
• Languages: English
• ISSNs: 0168-6496

Abstract

Abstract: Microorganisms within ectotherms must withstand the variable body temperatures of their hosts. Shifts in host body temperature resulting from climate change have the potential to shape ectotherm microbiome composition. Microbiome compositional changes occurring in response to temperature in nature have not been frequently examined, restricting our ability to predict microbe-mediated ectotherm responses to climate change. In a set of field-based observations, we characterized gut bacterial communities and thermal exposure across a population of desert arboreal ants ( Cephalotes rohweri ). In a paired growth chamber experiment, we exposed ant colonies to variable temperature regimes differing by 5°C for three months. We found that the abundance and composition of ant-associated bacteria were sensitive to elevated temperatures in both field and laboratory experiments. We observed a subset of taxa that responded similarly to temperature in the experimental and observational study, suggesting a role of seasonal temperature and local temperature differences amongst nests in shaping microbiomes within the ant population. Bacterial mutualists in the genus Cephaloticoccus (Opitutales: Opitutaceae) were especially sensitive to change in temperature—decreasing in abundance in naturally warm summer nests and warm growth chambers. We also report the discovery of a member of the Candidate Phlya Radiation (Phylum: Gracilibacteria), a suspected epibiont, found in low abundance within the guts of this ant species. Abstract : Top panel—Cephalotes rohweri ant colonies were moved into growth chambers programmed to warm (+1°C) and cool (−4°C) temperatures relative to observed hourly average nest temperatures in the field in the summer. Microbiome composition and abundance was assessed with 16S amplicon sequencing and qPCR. Bottom panel—In a complementary set of observations, we characterized naturally occurring nest temperatures within both the summer (September 2018) and winter (February 2019) and naturally occurring bacterial composition.