Dave Chandler,
Gill Davidson
University of Warwick
Insect pathology the early years

Anamorphic Ascomycete
Entomopathogenic fungi
•
Widespread in nature, especially soil.
•
Range of species, different properties.
•
Used as inundative biopesticides.
•
Can be valuable components of
IPM.

Chemical clones or bio-control agents?
• Inundative biopesticides: development = chemical model.
• Ignoring ecological attributes (Waage)
– numerical response,
– trade offs,
– conservation control.
• Lack of knowledge: affects biocontrol efficacy & environmental risk evaluation.

Ascomycete entomopathogenic fungi
• Natural abundance? Diversity? Ecosystem function?
• Are they ecologically obligate pathogens?
• Determinants of population structure?
• Population dynamics?
• How does virulence evolve?
• Lack meaningful species definitions.
• Theoretical framework for predicting environmental (non target) impacts of biocontrol releases.

Work outline
• Studying natural popns. of fungi in soils, esp.
Beauveria .
– Bidochka : biogeography of Beauveria & Metarhizium .
– Rehner: Beauveria phylogeny.
• Expt 1:
– Examined Beauveria from culture collection: collected from UK woodland & farm grassland.
• Expt 2:
– Sampling at a single farm site.

Galleria bait method

Experiment 1: Beauveria biogeography?: national scale
• Culture collection:
Beauveria isolates from 9 woods & 11 grasslands.
– Devon
– Somerset
– Gloucestershire
– Herefordshire
– Shropshire
– Berkshire
– Warwickshire
– Leicestershire

Beauveria biogeography: national scale
• Culture collection:
– Isolates from each location.
– 117 total, 85 wood, 32 grass.
• Sequence data:
– EF1a
– 28s rDNA gp I intron
– Beta tubulin, rDNA ITS
– DNA lyase, Beta locus
– Micro satellites.

EF1a woods & grassland
(includes 1 sequence each from Rehner clades A – F)
B. scarabaeicola EFCC2533
100
88
A :28/56 from woods
(exp 41/56)
63
98
100
B: 20/20 from woods
(exp 15/20)
C: 37 / 41 from woods
(exp 30/41)
100
100 clustal W, distance (NJ)
D ( B. caledonica ) none
E ( Cordyceps sp.) none
F ( B. amorpha ) none
Chi sq : habitat effect : p < 0.001 (pearson = 28, 2 df)

Expt 2: Fungi from different habitats in close proximity: Warwick Dept. farm
Grassland
10 ha
Stewardship
12 ha
Arable
7 ha

Expt 2: Fungi from different habitats in close proximity
Long close
Water meadows
Deep slade

arable steward grass hedge all samples Beau Met P. fa P. fu Lec
506 16 1 1 0 0
240
150
28
55
0.5
1
0
2
0
1
0
1
250
1146
34 0 5
28 0.6
2
11 0
3 0.3
Chi square (pearson) 68.7, 9 df, p < 0.001

EF1a Warwick dept farm
Constructed tree (NJ, distance) with
Beauveria isolates:
Hedgerow
Arable
Stewardship
Grassland
24
26
23
26
Total 99

EF1a Warwick dept. farm: hedge vs. fields
(includes 1 sequence each from Rehner clades A – F)
B. scarabaeicola EFCC2533
100
96
A :7/77 from hedge
(exp 19/77)
64
97
100
B: 1/2 from hedge
C: 16 / 20 from hedge
(exp 5/20)
100
100 clustal W, distance (NJ)
D ( B. caledonica ) none
E ( Cordyceps sp.) none
F ( B. amorpha ) none
Chi sq : habitat effect : p < 0.001 (pearson = 47, 6 df)

• Genetic groups in Beauveria have different habitat preferences. Why?
• Warwick farm study:
– Habitat type affects frequency of occurrence of fungi.
– Diff genera have diff habitat preferences?

Why does this matter?
• Bio-prospecting.
• Conservation control (habitat manipulation).
• Informs risk assessment.
• Generation & maintenance of diversity in an ‘asexual’ organism.

• USDA
Steve Rehner