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Systematics, Evolution, and Biodiversity

Section Symposium

Microbes Rulers of Us All: Microbial Interactions and Their Influence over Host Fitness

Gains and losses of bee-microbe symbioses

Sunday, November 13, 2022

3:56 PM – 4:19 PM PT

Location: Vancouver Convention Centre, Meeting Room 109

Presenting Author(s)

TH

Tobin Hammer

University of California
Irvine, California

Co-author(s)

AS

Alan E. Silva Cerqueira

University of Texas
Austin, Texas

Co-Author(s)

NM

Nancy Moran

University of Texas
Austin, Texas

Co-author(s)

NV

Nickole A. Villabona

University of California
Irvine, California
AR

Alejandro Reyes

Universidad de Los Andes
Bogotá, Distrito Capital de Bogota, Colombia
QM

Quinn McFrederick

University of California
Riverside, California
SB

Stephen Buchmann

University of Arizona
Tucson, Arizona
BD

Bryan N. Danforth

Cornell University
Ithaca, New York

Microbial symbionts are widespread and often have important roles in insect physiology. But these symbioses are also extremely variable, both in form and function: some insects have a single endosymbiont that performs a single function; others have a diverse gut microbiome that provides numerous services; and at least a few do not appear to house or rely on microbial symbionts at all. Evolutionary transitions among these different ‘modes’ are generally obscure, but the ecological and microbial diversity among bees provides an opportunity to study them. This talk will cover the gain and loss of bee-microbe symbioses. In Ptiloglossa, we have evidence for the gain of a unique lacto-fermentation symbiosis in the larval provisions. This brood cell microbiome appears to be unique from even a sympatric, sister bee species. I will discuss the possible origin and functional role of this symbiosis. There are also losses among social bees. In Melipona stingless bees, we recently discovered a genus-wide extinction of two ancient gut bacterial symbionts. These symbionts provide important benefits in other social bees, raising the question of how Melipona gets along without them. Bumble bees exhibit another, distinct form of symbiont loss: wild populations contain numerous individuals whose gut symbionts have been replaced with environmental microbes. I will discuss our recent field surveys documenting this phenomenon in both neotropical and temperate regions, and experiments testing thermal stress and senescence as potential causes. Collectively, bees provide insights into the dynamic nature of insect-microbe symbioses, and the host traits that explain microbiome diversity.