Impacts of Ozone Pollution on Plant-Pollinator Interactions

Daniel Stabler, Geraldine Wright, Jerry Barnes

Potential Influences on Bumblebee Foraging

Introduction Aims: • Investigate effect of ozone stress on plant

resource provisioning

• How nectar and pollen quality and quantity influences pollinator behaviour

Plant resource allocation • Dwarf broad beans (Vicia faba)

• Chronic stress

• Clean air control • 110 ppb ozone for 8 hours per day

• Acute stress • Transfer from O3 to clean air at flowering • Transfer from clean air to O3 at flowering

• Nectar and pollen collected

• HPLC analysis for carbohydrates and

amino acids

• Measured dry weight

Results • Number of flowers

Treatment

Trans - clean air Trans - O3 Clean air control Permanet O3

Ave

rage

num

ber o

f flo

wer

s pe

r gro

up

0

2

4

6

8

• No significant differences in number of flowers between any treatment

Results • Dry weight (biomass) • Ozone fumigation

has no influence on biomass

Treatment

Trans - clean air Trans - O3 Clean air control Permanent O3

Dry

wei

ght (

g)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

• So, are broad beans ozone tolerant?

Treatment

Trans - clean air Trans - O3 Clean air O3

Vol

ume

(ul)

0

1

2

3

4

5

6

7

Results • Volume of nectar

• Transfer causes

an increase in the volume of nectar provided

Results • Carbohydrate profile

Treatment

Trans -

clea

n air

Trans -

O3

Clean a

ir con

trol

Perman

ent O

3

conc

entra

tion

(Mol

es/li

tre)

0.0

0.5

1.0

1.5

2.0

2.5

FructoseGlucoseSucrose

• Plants moved from ozone into clean air at flowering produce twice the concentration of sucrose in the nectar

Results • Amino acid profile

0

500

1000

1500

2000

2500

conc

entr

atio

n (n

M/m

l)

Amino acids

Clean air control

Permanent O3

Trans into clean air

Trans into O3

Results • Amino acid total nectar composition

Treatment

Trans - clean air Trans - O3 Clean air control Permanent O3

Con

cent

ratio

n (n

M/m

l)

0

1000

2000

3000

4000

5000

6000

7000

• Total amino acid composition of nectar in plants grown under ozone and moved to clean air at flowering is more than double found in other treatments

Bumblebee taste • Can bees detect changes in carbohydrates

and amino acids?

• Representative solutions from HPLC analysis

• Consumption measured after 24 hours

Results • Bee choice experiments

Treatment

1M sucrose 2M sucrose

Vol

ume

cons

umpt

ion

(ml)

0.0

0.1

0.2

0.3

0.4

0.5

Treatment

sucrose-only 1µM amino acids 5µM amino acids

Vol

ume

cons

umpt

ion

(ml)

0.0

0.2

0.4

0.6

0.8

1.0

Carbohydrates Amino acids

Results • Honeybee PER to antennal stimulation with 0.1M Amino acids

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

Prob

abili

ty o

f res

pons

e

Amino acids

Results

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

thre phe isoleu suc1 lys meth hist suc2 lecu tryp val suc3

Prob

abili

ty o

f res

pons

e

Stimuli

•Honeybee drink responses on proboscis to 0.1M Amino acids

Future plans... • Pollen analysis from broad beans

• Identify amino acid and carbohydrate allocation in plant

tissue

• Free-flying bee experiments: • Effect of ozone on navigation to flowers • How affected reward quality influence foraging decisions

• Acknowledgements: • Sophie Derveau and Daniel Reed - bumblebee photography

• Koppert Uk Ltd. Bumblebee colonies