Exposure of honey bees
and other pollinating
species to pesticides
Mark Miles
Research & Development
Environmental Safety
Ecotoxicology – Bees
Bees vs. other flower visitors
• Supermarket vs. bar!
Exposure: risk assessment entry point
Hint...we’re
all collecting
pollen and
nectar from
flowers!
And we take
it back to our
nests or
colonies to
feed our
young
Pesticide Risk Assessment for
Pollinators:
Summary of a SETAC Pellston Workshop
Pesticide Risk Assessment for Pollinators
15–21 January 2011
Pensacola, Florida, USA
Edited by
David Fischer
Bayer CropScience LP, USA
Thomas Moriarty
Office of Pesticide Programs
US Environmental Protection Agency
Washington DC, USA
Major exposure sources and transfer of material
from field to colony:
Larvae
1. Spray
Drones
Forager exposure
Contact + dietary
Foragers taking nectar and pollen,
back to the colony for storage and use
2. Systemic movement from
seed/soil into pollen and nectar
Hive bees
Queen
Colony exposure
Pollen and bee bread
Nectar and honey
Water
Nurse bee secretions
Royal jelly
Minor exposure source and transfer of material
from field to colony:
Larvae
Hive bees
1. Spray
Drones
Forager exposure?
Foragers taking nectar, pollen,
back to the colony for storage
and use from drift exposure
3. Drift
Foragers taking water back
to the colony for storage and use
2. Systemic movement
From seed/soil
In-field puddle
Queen
Colony exposure
Pollen and bee bread
Nectar and honey
Water
Nurse bee secretions
Royal jelly
Consequences for risk assessment
Grasses?
Desert?
100% of input coming from treated field
Flowering crop
Military base?
Ice and snow?
Tier I/ laboratory
Concentration in field
X
consumption
= Exposure
Edge of field colonies/populations
Car parks?
Water, sea?
Trees
Bumble bee
Flowering crop
Honey bee
How can we improve
realism in exposure
estimates?
Solitary bee
Puddle of water
Weeds
Weeds
Edge of field colonies/populations
Look what’s in the colony
• Palynological evidence
• Bees forage on a variety of food sources
– Palynology does not confirm a single food source
• 100% of food cannot come from 1 place.
– E.g. Bumble bees 30% pollen from treated OSR
– E.g. Honey bees average
10-20% pollen from
maize
Residues in the colony
• Lots of information
– USA: Mullin et al 2010
– France: Chauzat et al 2010
– Spain: Bernal et al 2010
• Residues in
– Pollen, wax, honey
• On-going monitoring
– EU reference laboratory
– Health
• How do residue levels in colonies compare to
screening and tier I estimates?
Source data
Active substance
Application rate
g/ha
90th centile expected
residue in pollen from
field mg/kg
Chauzat et al, 201
hexaconazole
140
7.266
54.7
132.83
chlorpyriphos
480
24.912
95.3
261.41
deltamethrin
12.5
0.64875
39
16.63
flusilazole
200
10.38
16.2
640.74
imidacloprid
105
5.4495
0.9
6055.00
myclobutanil
57
2.9583
13.5
219.13
Bernal et al, 2010
acrinathrin
70
3.633
146.2
24.85
Bernal et al, 2010
metalaxyl
73
3.7887
2
1894.35
Bernal et al, 2010
difenoconazol
125
6.4875
71.5
90.73
Bernal High
et al, 2010
cypermethrin
50
2.595
34
76.32
Bernal et al, 2010
pendimethalin
800
41.52
55
754.91
Bernal et al, 2010
chlorothalonil
670
34.773
13
2674.85
Bernal et al, 2010
propiconazol
250
12.975
10.5
1235.71
Bernal et al, 2010
azoxystrobine
250
12.975
9.5
1365.79
Mediumspiromesifen
216
11.2104
63
177.94
Observed residues in
pollen (ug/kg)
90th centile dilution
degradation factor
Large discrepancy between
worse case residues in
pollen in the field and
those observed in colonies
Not a true like for like
comparison but shows we
may have some options
Low
Bernal
et al, 2010
Chauzat et al,
2010
Chauzat et al,
2010
Chauzat et al,
2010
Chauzat et al,
2010
Bernal et al, 2010
Dilution degradation
factor
1041.41
Describing exposure
Very simple form:
Exposure = Conc. x Food Consumption Rate
Exposure = (Abundance x Attractiveness x Conc.
x Food Consumption Rate)
But…
More than a single for sources so
Total exposure = Exp1+Exp2+Exp3….etc….
Possible refinements
• Modelling:
– Use landscape level data to determine the proportion of
each source
– Include residue level refinements
• Additional landscape data from field studies?
– Could be very useful when applied to crops not in flower
• Model scenarios for risk assessment
– Not a new idea (FOCUS, Birds and mammals)
– Model “diets” for different key scenarios
– E.g. herbicides in wheat, fungicide in vines, insecticides in
apple, seed treatment in maize
– Related to crop growth stage and availability of alternative
food sources
Building exposure and risk scenarios
Insecticide use
Spray application
– High input from
flowering crop
– Input from surrounding
areas less important
Also a scenario for seed
treatment
Edge of field colonies/populations
Building exposure and risk scenarios
Fungicide use in tree fruit
• At flowering: high input from crop
• Out of flowering: understory
vegetation
• Off-field
• Puddle
• What are the proportions?
• What are the appropriate species?
Edge of field colonies/populations
Building exposure and risk scenarios
Herbicide use
• Non-attractive crop
• Input from surrounding areas
• Vegetation at margins
• Adjacent crops
• Colonies will not be a field edge
• Colonies at adjacent field edge
• Also a scenario for seed treatment
• BUT…is this a scenario?
From point estimates…
10
9
8
7
Water
6
Adjacent crop
5
Dandelion pollen
4
Apple nectar
3
Apple pollen
2
1
0
Exposure
Fictitious data for illustration purposes for orchard scenario
…to residue profiles?
3,5
3
2,5
2
Apple
1,5
Dandelion
Water
1
0,5
0
0
2
4
6
-0,5
Fictitious data for illustration purposes
8
10
Real colony and population exposure
• Exposure to the in-field residue levels only is
probably too simplistic and over conservative
• Bees forage on a variety of food sources
– Palynology does not confirm a single food source
• In-colony residues are lower than in-field
– Dilution – with other food sources
– Degradation
– Honey bee colonies can be thought of as an organism
(ADME)
– Food processing for larvae
– Food processing for storage (effect of bee bread)
Thank you for your attention