Symbiosis and coevolution in insect-microbe communities

Nicole Gerardo Emory University, Department of Biology

Nancy Lowe, Ben Parker

(Kolenbrander et al. Micro and Molec Biol Rev 2002)

Beneficial microbes protecttheir aphid hosts from pathogens and parasites

Dr. Nicole Gerardo Emory University, Department of Biology

Nancy Lowe, Ben Parker

aphidsaphids

pathogenparasite

pathogenparasite

aphidsaphids

pathogenparasite

bacteriaand

viruses

fungi

parasitoid wasps

aphidsaphids

pathogenparasite

image from A.E. Douglas

Buchnera aphidicola

primary symbioticbacteria

Symbiosisclose, long-term interactions between biological species

aphidsaphids

pathogenparasite

Serratia symbiotica (SS) Hamiltonella defensa (HD)

Regiella insecticola (RI)

secondary symbioticbacteria

image from A.E. Douglas

Symbiont-conferred protection

Symbiont-conferred protection

SS HD

SSSS

SSSS

SS

SS

HDHD

HD

HDHD

HD

Oliver et al. (2003, PNAS)– Harboring either Serratia symbiotica (SS) or Hamiltonella defensa

(HD) increases an aphid’s survival after parasitoid wasp attack.

Symbiont-conferred protection

RIRI

RI

RIRI

RI

HDHD

HDHD

HD

HDSSSS

SSSS

SS

SS

no secondary Serratia Hamiltonella Regiella

Oliver et al. (2003, PNAS)– Harboring either Serratia symbiotica (SS) or Hamiltonella defensa

(HD) increases an aphid’s survival after parasitoid wasp attack.

Symbiont-conferred protection

RIRI

RI

RIRI

RI

HDHD

HDHD

HD

HDSSSS

SSSS

SS

SS

no secondary Serratia (SS) Hamiltonella (HD) Regiella (RI)

0

5

10

15

20

25

R T U

mean

# a

ph

ids p

ara

sit

ized

no mutualist

mutualist

SS HD RI

Oliver et al. (2003, PNAS)– Harboring either Serratia symbiotica (SS) or Hamiltonella defensa (HD)

increases an aphid’s survival after parasitoid wasp attack.

Scarborough et al. (2005, Science)– Harboring Regiella insecticola (RI) protects aphids from Pandora

neoaphidis, a fungal pathogen.

Symbiont-conferred protection

Oliver et al. (2003, PNAS)– Harboring either Serratia symbiotica (SS) or Hamiltonella defensa (HD) increases an

aphid’s survival after parasitoid wasp attack.

Scarborough et al. (2005, Science)– Harboring Regiella insecticola (RI) protects aphids from Pandora neoaphidis, a fungal

pathogen.

Gerardo & Moran (in prep)

Symbiont-conferred protection

Harboring either Serratia symbiotica (SS) or Hamiltonella defensa (HD) increases an aphid’s survival slightly after being fed a bacterial pathogen.

surv

ival

of s

ymbi

otic

aph

ids

rela

tive

to a

sym

biot

ic a

phid

s

SS HD RI

aphidsaphids

image from A.E. Douglas