what factors limit fruit production in the lowbush ... · bumble bees buzz (specialist) honey bees...
TRANSCRIPT
What factors limit fruit production in the lowbush blueberry, Vaccinium angustifolium?
Melissa Fulton and Linley Jesson
University of New Brunswick
Barriers to fruit production
Pollen limitation
Fruitset
Resources
Genetics
Nutrients
Disease
Pollen quantity
Pollen quality
Pollinator abundance -specialists -generalists
Pollinator behaviour -specialists -generalists
Lowbush blueberry
Specialist flower: Vibrate anthers to release pollen (buzz pollination)
Vaccinium angustifolium
Linley Jesson Linley Jesson
Duncan MacGillivray
Duncan MacGillivray
Bumble bees buzz (specialist) Honey bees cannot buzz (generalist)
Leafcutters cannot buzz (generalist)
Duncan MacGillivray
All 3 bees are used as managed pollinators
Robyn Shortt
Does pollen quantity limit reproduction (fruitset)? Do managed pollinators affect blueberry reproduction? If so, which pollinators? How do pollinators forage in blueberry fields and how might their behaviour affect fruit production?
Pollen limitation Pollen deposition (Neguac 2010 & 2011)
Neguac
St. Stephen 2009 & 2010: Honeybees
2010 & 2011 Bumblebees Leafcutters Honeybees & all combinations
- Open pollination
- Supplemental pollen
(outcross pollen)
Fru
itset
Pollen quantity Pollen quality
Clone shoots
mean of all populations per region
n=10
Pro
port
ion F
ruitset
n=10 n=24 n=24
Open Supplemental mean +/- SE
Does pollen quantity limit reproduction (fruitset)? yes Do managed pollinators affect blueberry reproduction? If so, which pollinators? How do pollinators forage in blueberry fields and how might their behaviour affect fruit production?
Neguac 2010 & 2011
Pollen limitation not reduced by managed pollinators
Late season
Early season
C control
B bumble
H honey
L leafcutter
& all combinations
H p<0.05
HB p<0.05
s
tig
mati
c p
oll
en
lo
ad
population Neguac 2010 & 2011
Late season
Early season
C control
B bumble
H honey
L leafcutter
& all combinations
H p<0.05
HB p<0.05
s
tig
mati
c p
oll
en
lo
ad
population Neguac 2010 & 2011
High pollen deposition But still pollen limited Pollen Quality
Weak effect of native pollinator abundance on fruitset
Count of honeybees per 20 min Count of Andrena per 20 min
Does pollen quantity limit reproduction (fruitset)? yes Do managed pollinators affect blueberry reproduction? If so, which pollinators? very weak effect native pollinators How do pollinators forage in blueberry fields and how might their behaviour affect fruit production?
Honey bee Bumble bee Leafcutter bee
Tukey contrasts: Bombus - Apis = 0.6 Megachile - Apis <0.0001 Megachile - Bombus <0.0001 Visits: Honey 59/hour Bumble 89/hour Leafcutter 10/hour
Flo
wers
per
inflore
scence
Does pollen quantity limit reproduction (fruitset)? yes Do managed pollinators affect blueberry reproduction? If so, which pollinators? very weak effect native pollinators How do pollinators forage in blueberry fields and how might their behaviour affect fruit production? most metrics of bee behaviour similar
Pollen limitation
Fruitset
Resources
Genetics
Nutrients
Disease
Pollen quantity
Pollen quality
Pollinator abundance -specialists -generalists
Pollinator behaviour -specialists -generalists
Su
pp
lem
en
tal fr
uit
set
Open fruitset
Regional variation indicates other factors
mean for each population (68 fields)
St. Stephen 2009 St. Stephen 2010 Neguac 2010 Neguac 2011
p<0.00001
Su
pp
lem
en
tal fr
uit
set
Open fruitset
mean for each population (68 fields)
St. Stephen 2009 St. Stephen 2010 Neguac 2010 Neguac 2011
p<0.00001
Regional variation indicates other factors
Disease Resource availability Native pollinator regimes Genetics - pollen viability, plant vigour
Significance of research
Adding generalist pollinators :
weak or no effect (on FS and PL)
Adding specialist pollinators:
no obvious effect (on FS and PL)
Native pollinators having important
contribution?
Likely significant role of selfing in
reducing fruitset
Duncan MacGillivray
Bumblebees
Leafcutters
Honeybees
Robyn Shortt
Thank You