Predispersal seed predation of
Wyethia amplexicaule, Crepis
acuminata, and Agoseris glauca
Robert L. Johnson and Val Jo Anderson
Brigham Young University
project
• Document seed predation in select forb species
• Document occurrence of pest parasitoids
• Effect of treatment with imidacloprid
methods
• 3 plant populations
• 20 plants – nearest plant to point on transect bisecting
population
• 5 random plants per imidacloprid treatment
– soil drench
– spray
– control
• Seed heads harvested following anthesis and reared in
the lab
• Following insect emergence, individual seed were
examined for damage
Imidacloprid
treatment
Soil drench: 0.5
gallons solution =
1.2 grams active
ingredient
Spray: foliar spray
until solution begins
dripping from foliage
Wyethia amplexicaulis
Reared capitula
2,256
Neotephritis finalis
2256
Trupanea nigricornis
186
Melanagromyza sp.
15
Lepidoptera
24
% seed damage
M
or
e
95
%
90
%
85
%
80
%
75
%
70
%
65
%
60
%
55
%
50
%
45
%
40
%
35
%
30
%
25
%
20
%
15
%
10
%
5%
0%
# samples
Seed damage
60
average=39.0%
40
20
0
Agoseris glauca
Reared capitula
575
Campiglossa sp.
155
Diptera (unknown)
18
Seed damage
600
500
# samples
400
average=8.1
300
200
100
0
0%
1-20%
21-40%
41-60%
% seed damage
61-80%
81-99%
More
Imidacloprid treatment:
site x treatment (p<0.01)
b
18.0%
16.0%
percent seed damage
14.0%
12.0%
10.0%
8.0%
a
a
a
6.0%
4.0%
2.0%
0.0%
a
a
Manti Ridge
Teat Mountain
habitat
control
spray
drench
a
a
a
Willow Creek
Crepis acuminata
Reared capitula:
2859
Campiglossa sp
52
Phycitodes albatella
133
subsp. mucidella
Seed damage
220
200
180
160
average=12.4%
# samples
140
120
100
80
60
40
20
0
0%
1-20%
21-40%
41-60%
% seed damage
61-80%
More
Imidacloprid treatment:
habitat x site x year (p<0.01)
10.0%
9.0%
percent seed damage
8.0%
7.0%
6.0%
5.0%
4.0%
3.0%
2.0%
1.0%
0.0%
Squaw Peak
Sheep Creek
West Mountain
Squaw Peak
2006
Sheep Creek
2007
control
spray
drench
West Mountain
conclusions
• Significant seed damage can occur in wild plant
populations
– Year and site influence percent damage
• A new seed predator, host associations, and parasitoids
were discovered
• Capitulum size of W. amplexicaulis influences pest
abundance per capitulum but not total percent seed
damage
• Imidacloprid treatment can reduce seed damage – soil
drench provides greater pest control but was not
significant most of the time at the 95% confidence level.
Impact of Habitat Alterations to Bee Diversity in
Sagebrush and Pinyon/Juniper Communities of the
Eastern Great Basin
Robert L. Johnson and Val Jo Anderson
Brigham Young University
project
Hypothesis: introduced grassland habitats support lower
bee diversity than neighboring native habitats
•
•
quantify the differences/similarities in bee diversity between natural
and altered habitats
– 3 sites x 4 habitats x 3 traps per = 36 traps
– Malaise traps
– Continuous sampling – two week intervals
quantify vegetation in each habitat
– flowering plant density
– plant cover
sagebrush
pinyon/juniper
cheatgrass
crested wheatgrass
Results
• 162 taxa
• 44 singletons
• 21 doubletons
– 40.1 % rare
Bee abundance – site x year (p=0.04)
100.0
b
90.0
average bee abundance/trap
80.0
70.0
60.0
ab
50.0
40.0
a
a
a
a
30.0
20.0
10.0
0.0
Antelope Valley
Tintic Valley
site
2006
2007
Yuba
Bee abundance by habitat (p<0.01)
120
c
average bee abundance per trap
100
80
60
40
a
a
20
b
0
cheatgrass
crested wheatgrass
habitat
juniper
sagebrush
Bee richness by habitat (p<0.01)
35
c
average bee bee richness per trap
30
25
20
15
a
a
b
10
5
0
cheatgrass
crested wheatgrass
habitat
juniper
sagebrush
3D MDS of bee diversity by habitat
Transform: Log(X+1)
Resemblance: S17 Bray Curtis similarity
3D Stress: 0.19
Habitat
Cheatgrass
Crested
Juniper
Sagebrush
Prevalent and modal bee species
Cheatgrass
bee species
Lasioglossum (Dialictus) hyalinum
Lasioglossum (Lasioglossum) sisymbrii
Lasioglossum (Dialictus) incompletum
Eucera actuosa Cresson 1878
Lasioglossum (Dialictus) albohirtum
Lasioglossum (Dialictus) sed i
Eucera lutziana (Cockerell) 1933
Agapostemon angelicus Cockerell 1924
Lasioglossum (Dialictus) pruinosiforme
Lasioglossum (Evylaeus) pulveris
Lasioglossum (Dialictus) sp.
Melissodes sp.
Anthophora urbana Cresson 1878
Lasioglossum (Dialictus) sp. 19
Lasioglossum (Evylaeus) incompletum
Perdita albonotata Timberlake 1954
% frequency
88.9%
83.3%
77.8%
50.0%
50.0%
50.0%
44.4%
38.9%
38.9%
38.9%
33.3%
33.3%
27.8%
27.8%
27.8%
27.8%
rank
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
modal
species
x
x
x
habitat
specific
x
x
x
x
x
x
x
x
x
Sagebrush
bee species
Eucera actuosa Cresson, 1878
Eucera lutziana (Cockerell, 1933)
Osmia sp.
Lasioglossum (Dialictus) sp. K1
Lasioglossum (Dialictus) hyalinum
Lasioglossum (Lasioglossum) sisymbrii
Eucera fulvitarsis Cresson, 1878
Lasioglossum (Dialictus) sp.
Andrena piperi Viereck, 1904
Anthophora ursina Cresson, 1869
Lasioglossum (Dialictus) sedi
% frequency
55.6%
55.6%
55.6%
44.4%
38.9%
38.9%
33.3%
33.3%
27.8%
27.8%
27.8%
rank
1
2
3
4
5
6
7
8
9
10
11
modal
species
habitat
specific
x
x
45
40
40
35
# species
30
28
25
21
20
15
11
10
9
7
8
9
9
7
5
1
0
0
cheatgrass
crested wheatgrass
juniper
habitat
singletons
habitat specific
modal
sagebrush
Plant richness – habitat x site (p=0.04)
14
12
10
8
6
4
2
0
Antelope Valley
Tintic Valley
Yuba
site x habitat interaction
cheatgrass
crested w heatgrass
juniper
sagebrush
3D MDS of flowering plant
diversity by habitat
Transform: Log(X+1)
Resemblance: S17 Bray Curtis similarity
3D Stress: 0.13
Habitat type
Cheatgrass
Crested
Juniper
Sagebrush
Herbaceous cover
30%
25%
% cover
20%
15%
10%
5%
0%
Cheatgrass
Crested wheatgrass
habitat
Sagebrush
Juniper
3.5
3
2.5
log10(x+1)
Bee and
flowering plant
phenology
2
1.5
1
0.5
total bee abundance
O
ct
23
O
ct
9
Se
p
25
11
Se
p
Au
g
28
14
Au
g
Ju
l
31
17
Ju
l
l
Ju
3
19
Ju
n
n
Ju
5
ay
M
M
ay
22
abundance
8
24
Ap
r
0
mean flowering plants/hectare2
90
80
70
# species
60
50
40
30
20
10
richness
bee richness
plant richness
O
ct
23
O
ct
9
Se
p
25
11
Se
p
Au
g
28
Au
g
14
Ju
l
31
Ju
l
17
Ju
l
3
Ju
n
19
n
Ju
5
M
ay
22
M
ay
8
24
Ap
r
0
Conclusions
1.
2.
3.
4.
5.
6.
Bee diversity is influenced by habitat, site, and year
A strong relationship exists between flowering plant
diversity and bee diversity
Pinyon/juniper habitat generally supports the greatest
flowering plant and bee diversity
Crested wheatgrass supports the lowest bee
abundance and diversity
Mature pinyon/juniper stands have high conservation
value for bee populations
Metrics for restoration success should factor in forb
abundance