SLIDE 1
Sustainable insect exploitation, management and climate change
Casper Nyamukondiwa
Biological Sciences and Biotechnology, Botswana International University of Science and Technology (nyamukondiwac@biust.ac.bw)
Sustainable insect exploitation, management and climate change - - PowerPoint PPT Presentation
Sustainable insect exploitation, management and climate change - - PowerPoint PPT Presentation
Sustainable insect exploitation, management and climate change Casper Nyamukondiwa Biological Sciences and Biotechnology, Botswana International University of Science and Technology (nyamukondiwac@biust.ac.bw) Climate is changing Changes in
SLIDE 2
SLIDE 3
Changes in biogeography pattern
SLIDE 4
Heat and cold snaps
- 5
5 10 15 20 25 30 35
Temperature (°C)
A
SLIDE 5
Implications of global change
- Short generation times
- More generations per year
- Increased T°C and DD accumulation
- Reduced overwintering- more pest pressure
- Asynchrony between host-natural
enemy
- Reduced efficacy of biological control
SLIDE 6
Implications of global change
- Creation of new structures in native
pest abundance
- Emergence of 2° to 1° insect pests
- Decreased food and nutrition security
- Modification of habitats
- Pest colonization of new previously unfavorable
habitats
- Loss of natural enemy biological diversity/ lack of
fitness/efficacy
- Loss of ecosystem function
- Consequence on pest management/food security
SLIDE 7
- (1) High temperature tolerance
- Plutella xylostella vs Cotesia vestalis
- C. vestalis adult
- P. xylostella larvae
- P. xylostella adult
Treatment
3.0 3.5 4.0 4.5 5.0 5.5 6.0
Heat knockdown time (minutes) a b a
Loss coevolved basal and plastic responses to temperature may underlie trophic level host- parasitoid interactions under climate change
- C. vestalis adult
- P. xylostella larvae
- P. xylostella adult
Treatment
37 38 39 40 41 42 43 44 45 46 47 48 49
Critical Thermal Maxima (°C) e d b c bc ab d a ab
0.5°C/min 0.25°C/min 0.12°C/min
SLIDE 8
Low temperature tolerance
- C. vestalis adult
- P. xylostella larvae
- P. xylostella adult
Treatment
2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.8 4.0
Chill comma recovery time (minutes) b a a
- C. vestalis adult
- P. xylostella larvae
- P. xylostella adult
Treatment
- 6
- 5
- 4
- 3
- 2
- 1
1 2 3
Critical Thermal Minima (°C) a a a b b cd d bc c
0.5°C/min 0.25°C/min 0.12°C/min
SLIDE 9
High/low temperature tolerance
31 34 36 38 40 42 44 46
Temperature (°C)
- 20
20 40 60 80 100 120
Survival (%)
- C. vestalis adult
- P. xylostella larvae
P.xylostella adult
- 20
- 18
- 16
- 12
- 8
- 6
- 2
2
Temperature (°C)
- 20
20 40 60 80 100 120
Survival (%)
SLIDE 10
Thermal tolerance traits vs prevailing microclimates
5 / 1 1 / 2 1 5 7 / 1 1 / 2 1 5 9 / 1 1 / 2 1 5 1 1 / 1 1 / 2 1 5 1 / 1 1 / 2 1 6 3 / 1 1 / 2 1 6 5 / 1 1 / 2 1 6 7 / 1 1 / 2 1 6
- 10
10 20 30 40 50
Temperature (°C) Dates Temperature (°C)
Pxa Pxl Cv
Results show thermal divergence on an economically important host- parasitoid system
SLIDE 11
Thermal resilience may shape population abundance of two sympatric congeneric species (Hymenoptera: Braconidae)
- Cotesia flavipes & Cotesia sesamiae
- 15
- 13
- 11
- 9
- 7
- 5
- 3
- 1
1 3 4 5
Temperature (oC)
20 40 60 80 100
Survival (%) A
0.5 hr 1 hr 2 hr 4 hr
- 15
- 13
- 11
- 9
- 7
- 5
- 3
- 1
1 3 4 5
Temperature (oC)
20 40 60 80 100
Survival (%) B
0.5 hr 1 hr 2 hr 4 hr
Cotesia sesamiae Cotesia flavipes
SLIDE 12
Thermal resilience may shape population abundance of two sympatric congeneric species (Hymenoptera: Braconidae)
Cotesia sesamiae Cotesia flavipes
35 36 37 38 39 41 42 44
Temperature (oC)
20 40 60 80 100
Survival (%) C
0.5 hr 1 hr 2 hr 4 hr 35 37 38 39 40 42 44
Temperature (oC)
20 40 60 80 100
Survival (%)
0.5 hr 1 hr 2 hr 4 hr
D
SLIDE 13
Cotesia sesam iae Cotesia flavipes
Species
37 38 39 40 41 42 43 44 45 46
Critical thermal maxima (oC)
a b
B
Cotesia sesamiae Cotesia flavipes
Species
16 18 20 22 24 26 28 30
Heat knock-down time (minutes)
a b
High temperature tolerance
SLIDE 14
Low temperature tolerance
Cotesia sesam iae Cotesia flavipes
Species
0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0
Critical thermal minima (oC)
a b
A
Cotesia sesamiae Cotesia flavipes
Species
2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
Chill coma recovery time (minutes)
a b
SLIDE 15
Way forward
Use of evolutionary physiology?
- Phenotypic plasticity (=thermal preconditioning)
- As a method of improving insect mass rearing
techniques
- For improvement of biocontrol programs.
- Through evolutionary resilience
- 5
5 10 15 20 25 30 35
Temperature (°C)
A
Take T°C in ‘bug’ factory Against T°C in natural habitat And consequences of fitness and efficacy of mass reared natural enemies for biocontrol??
SLIDE 16
Detailed reading
SLIDE 17