Spruce Budworm Tordeuse des bourgeons de l'epinette at Bonanza Creek LTER: A clear case of temperatu

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Spruce Budworm (Tordeuse des bourgeons de
l'epinette)at Bonanza Creek LTER A clear case
of temperature thresholds in a warming climate
Glenn Patrick Juday, Professor of Forest
EcologySkeeter Werner, USDA FS, PNW Research
Station (retired)Robert A. Ott, consultant?
Jim Kruse, USDA Forest Service SPF
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WARM TEMPERATURE ANOMALIES IN BOREAL ALASKA
Strong negative tree growth anomaly of
negative responders - w. spruce on
low-elevation productive sites central AK - w.
spruce (42) at treeline
Spruce bark beetle outbreak behavior in
southcentral Alaska - shift from 2-yr. to 1-yr.
life cycle
Large total area burned - early start to
fire season - multiple simultaneous fires -
large fires - lack of mid-summer season-ending
precipitation event - active late fire season
- continued vigorous spread - some fires
extinguished by first snows of season -
smouldering through the winter
Decrease in open water/lake surface area
Spruce budworm reproduction/outbreak?
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Photo Paul Renschen
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Spruce Budworm, Choristoneura fumiferana
Photo Robert A. Ott
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PART 1. ITS A BIG DEAL. IT MATTERS.
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Spruce budworm outbreaks Natural disturbance
system - especially in NE North America Cause
large-scale mortality of spruce and balsam fir
- uncertainty in future forest structure and
productivity The most destructive forest pest
in Canada - causes 40 of the 81107 million
m3 of timber volume lost to insects and
disease each year. Three major spruce budworm
outbreaks in the 20th century - beginning
1910, 1940, and 1970, - maximum extents of 11,
25, and 58 million hectares - late 20th century
in northwest Canada (Alaska)
MacLean, D.A., Porter, K.B., MacKinnon, W.E.,
Beaton, K.P. 2000. Spruce budworm decision
support system lessons learned in development
and implementation. Computers and Electronics in
Agriculture 27 293 314. Power, J.M., 1991.
National data on forest pest damage. In Brand,
D.G. (Ed.), Canadas Timber Resources. Can. For.
Serv., Petawawa National Forestry Inst., Chalk
River, ON. Inf. Rep. PI-X-101. pp. 119129.
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Budworm populations Usually regulated by
combinations of several natural factors -
insect parasites - vertebrate predators -
invertebrate predators, - adverse weather
conditions. During prolonged outbreaks -
stands heavily defoliated eventually budworm
starvation becomes important mortality factor.
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Explaining spruce budworm outbreak behavior a
popular pastime Theory 1. The catastrophe theory
of budworm outbreaks holds that major
infestations occur every 40-60 years, as the
result of a cusp-catastrophe event, whereby
populations jump suddenly from endemic to
epidemic levels. Theory 2. Outbreaks are the
result of spatially synchronized population
oscillations that are caused by delayed
density-dependent feedback (from various
mortality agents) which are synchronized via a
process of entrainment, or alignment of period
and phase to the period and phase of an external
rhythm.
In the far north spruce budworm reproductive
success is clearly heat limited, and sensitive to
a variety of temperature controls.
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PART 2. YOU GOTTA KNOW THE BIOLOGY OF THIS
CRITTER
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Several Choristoneura actors
C. fumiferana C. biennis C. orae C. occidentalis
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Spruce budworm is distributed across the
continuous forest zone, but generally is not
mapped all the way to northern tree limit.
80 to 100 forested
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The spruce budworm completes its life cycle
within a 12-month period, but spread across 2
different years.
August
First year events
Second year events
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SPRUCE BUDWORM LIFE CYCLE
The spruce budworm completes its life cycle
within a 12-month period, but spread across 2
different years. Larval Stage 1 The eggs hatch
to produce the first instar (L1) of the
budworm. Larval Stage 2 The first instar (L1)
caterpillars develop into the second instar (L2)
caterpillars, which move by wind and find sites
under bark scales. Here, they will spin silken
cocoons for hibernation (overwintering). Larval
Stage 3 In May, L2 budworm, which are yellowish
with dark brown heads, develop to the next instar
(L3), which either bore into needles or buds or
spin silken webbing around new shoots and begin
to feed on the needles within. Larval Stages 4,
5, 6 The most damage to the foliage normally
occurs early to mid-June when the larvae are in
their final stage of development (L6). Larger
budworms with brown bodies (18-24 mm in length),
black heads, and two rows of paired whitish spots
down the back, can be spotted on shoots in
June. Pupae After L6, the budworms stop feeding
and develop into brownish pupae, which in turn
become moths. Moths (Adult) Moths mate and then
the female lays eggs. Eggs Up to 300 green eggs
per female are laid in masses of about 15-50 eggs
on the underside of the needles.
Source http//www.srd.gov.ab.ca/forests/health/in
sects/sprucebudworm.aspx
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Spruce budworm 2nd instar
Spruce budworm egg mass
spruce bud
Spruce budworm 3rd instar
spruce bud
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Spruce budworm 4th instar
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Larva stage 6 causes most damage to the
foliage brown body, black head, two rows
of paired whitish spots down the back,
on shoots in June.
Photo Robert A. Ott
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Spruce budworm adult moth
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PART 3. SOME WAY THAT TEMPERATURE MIGHT MATTER.
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Overwintering mortality in the spruce budworm,
Choristoneura fumiferana (Clem.), was measured
between 1983 and 1990 in several natural stands
of balsam fir, Abies balsamea (L.), in Quebec and
Ontario. Overwintering losses (disappearance of
larvae) averaged 25.2, occurred mostly in late
summer and early fall, . We conclude that
overwintering mortality does not result from
adverse winter weather conditions or from gradual
loss of hibernacula. Regniere, J. and
Duval. P. 1998. Overwintering mortality of spruce
budworm, Choristoneura fumiferana (Clem.)
(Lepidoptera Tortricidae), populations under
field conditions. Canadian Entomologist 130
(1)13-26.
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Temperature-dependent developmental rate of
spruce budworm has been investigated extensively
for almost all developmental stages L1
developmental rate, however, has been overlooked.
Here, we divide L1 development into subphases
based on morphological changes and behavioral
events observed during the development of the
stadium. We examine the effects of temperature on
development time and survival rate for each
development phase.L1 development time was
significantly increased as rearing temperatures
decreasedAlthough it took only a few more days
for L1 to construct hibernacula at lower
temperatures compared with insects reared at
higher temperatures, it took a few additional
weeks for the larvae to reach the 2nd stadium
when they enter diapause. Therefore, temperature
could have a significant impact on the timing of
diapause initiation. Han, E. Bauce, E.
Trempe-Bertrand, F. 2000. Development of the
first-instar spruce budworm (Lepidoptera
Tortricidae). Annals of the Entomological Society
of America 93(3) 536-540.
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Temperature control of spruce budworm 1st instar
larva development rate (August).
gs green substance
Han, E. Bauce, E. Trempe-Bertrand, F. 2000.
Development of the first-instar spruce budworm
(Lepidoptera Tortricidae). Annals of the
Entomological Society of America 93(3) 536-540.
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Consolidation of green substance (gs) and
formation of hibernaculum (hi) (August
temperature control).
Han, E. Bauce, E. Trempe-Bertrand, F. 2000.
Development of the first-instar spruce budworm
(Lepidoptera Tortricidae). Annals of the
Entomological Society of America 93(3) 536-540.
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Excretion of green pellets in 1st
instar. (August temperature control).
Han and Bauce (1993) reported that the excretion
of green substance resulted in a lower
super-cooling point as the insect prepared for
overwintering. It is also possible that the green
substance serves primarily as a camouflage for
egg protection as spruce budworm eggs are laid on
green needles and may be vulnerable to predation.
Han, E. Bauce, E. Trempe-Bertrand, F. 2000.
Development of the first-instar spruce budworm
(Lepidoptera Tortricidae). Annals of the
Entomological Society of America 93(3) 536-540.
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Molt into 2nd instar larva. (August
temperature control).
Han, E. Bauce, E. Trempe-Bertrand, F. 2000.
Development of the first-instar spruce budworm
(Lepidoptera Tortricidae). Annals of the
Entomological Society of America 93(3) 536-540.
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Han, E. Bauce, E. Trempe-Bertrand, F. 2000.
Development of the first-instar spruce budworm
(Lepidoptera Tortricidae). Annals of the
Entomological Society of America 93(3) 536-540.
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In Alaska, significant budworm damage was
detected in 1978 on white spruce in many
residential and park areas of Anchorage.
(Holsten USDA Forest Service, Alaska Region
Leaflet R10-TP-11)
Analysis G. Juday
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3.5o C 100yr-1
Analysis G. Juday
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A stochastic model of spruce budworm,
Choristoneura fumiferana (Clemens), phenology on
balsam fir, Abies balsamea (L.) Miller, and white
spruce, Picea glauca (Moench) Voss, in northern
Ontario was developed based on relationships
between the proportion of budworms in each stage
(second instar to adult) and accumulated
degree-days (DD). Repeated calculations
indicated that 8 degree C (46 F) was a suitable
threshold for degree-day calculations. Tests of
the model with independent data showed that it
simulated spruce budworm development excellently.
Model performance was superior compared with a
previously published spruce budworm phenology
model. Lysyk, T.J. 1989. Stochastic model of
eastern spruce budworm (Lepidoptera Tortricidae)
phenology on white spruce and balsam fir. Journal
of Economic Entomology 82 (4)1161-1168.
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Growing Degree-day calculation
DAY 1 Daily High 70 F Daily Low
50 F Mean daily 60 F Base temp. 46 F GDD
14 F
DAY 2 Daily High 60 F Daily Low
40 F Mean daily 50 F Base temp. 46 F GDD
4 F
DAY 3 Daily High 52 F Daily Low
40 F Mean daily 46 F Base temp. 46 F GDD
0 F
3-day accumulation 18 GDD F
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Accumulated degree days associated with peak
stages of spruce budworm development
2nd instar 197 GGD(F) 3rd instar 217
GGD(F) 4th instar 280 GGD(F) 5th instar
366 GGD(F) 6th instar 492 GGD(F) Pupa
698 GGD(F) Adult 818 GGD(F) Base
temperature 46 F. Starting date (Lysyk) 01
March Starting date (Juday -AK) 01 April
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Accumulated degree days associated with peak
stages of spruce budworm development
2nd instar 109 GGD(C) 3rd instar 121
GGD(C) 4th instar 156 GGD(C) 5th instar
203 GGD(C) 6th instar 273 GGD(C) Pupa
388 GGD(C) Adult 454 GGD(C) Base
temperature 8 C. Starting date (Lysyk) 01
March Starting date (Juday -AK) 01 April
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WE TEMPORARILIY INTERRUPT THIS PRESENTATION IN
ORDER TO BRING YOU AN IMPORTANT MESSAGE ABOUT
RECENT TEMPERATURE TRENDS IN BOREAL ALASKA
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McGrath (foothils of Alaska Range)
Bettles (foothills of Brooks Range)
Analysis G. Juday
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Fairbanks
Talkeetna
Bettles
Analysis G. Juday
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Last spring frost
cold season
growing season
First fall frost
cold season
Analysis G. Juday
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2007

• Factors
• days 70F (21.1 C)
• days grow season
• mean daily min. T
• mean daily max. T
• min. T of coldest 1 day

Analysis G. Juday
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WE NOW RESUME OUR REGULARLY SCHEDULED
PRESENTATION
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1995
1990
2004
Data start
no budworms
Budworm density data R. Werner, J. Kruse
Budworm area data AK For. Health Survey
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1977
2004
1994
1988- 1990
Data National Weather Service Analysis G. Juday
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2004- 2007
1993- 1995
Analysis G. Juday
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Analysis G. Juday
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1995
Acreage Data Alaska Forest Health Survey
Analysis G. Juday
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no budworms
Budworm data R. Werner, J. Kruse
Data start
Analysis G. Juday
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1-yr. lag
no budworms
Budworm data R. Werner, J. Kruse
Data start
Analysis G. Juday
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PART 4. OK, SO ITS HERE, SO WHATS GOING TO
HAPPEN?
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(estimated)
Data G. Juday
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NE British Columbia - Some useful recent
articles Alfaro, R.I., Taylor, S.P. R.G. Brown
and J.S. Clowater. 2000. Susceptibility of
Northern British Columbia forests to spruce
budworm defoliation. For. Ecol. and Management.
145 181-190. Burleigh, J.S., R.I. Alfaro, J.H.
Borden, and S. Taylor. 2002. Historical and
spatial characteristics of spruce budworm
Choristoneura fumiferana (Clem.) (Lepidoptera
Tortricidae) outbreaks in northeastern British
Columbia. Forest Ecology and Management 168
301-309. Magnussen, Paul Boudewyn and René
Alfaro. 2004. Spatial prediction of the onset of
spruce budworm defoliation. The Forestry
Chronicle 80(4) 485-494.
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Cumulative Tree Mortality in white spruce (39
ecological impact plots in the Fort Nelson, B.C.
Forest District)
Budworm
No budworm
Mortality from high water table and windthrow
Source Natural Resources Canada http//cfs.nrcan.
gc.ca/subsite/budworm/impact
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Dendron tree Oikein dwell
Cape May Warbler (Dendroica tigrina) the
fortunes of its populations are largely tied to
the availability of spruce budworms, its
preferred food. http//www.birds.cornell.edu/AllA
boutBirds/BirdGuide/Cape_May_Warbler_dtl.html
Not known to breed in Alaska. Has occurred at
Fairbanks, Haines, Pt. Barrow. Armstrong.
1983. Birds of Alaska.
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Vermis worm
Tennessee Warbler (Vermivora peregrina) A
dainty warbler of the Canadian boreal forest, the
Tennessee Warbler specializes in eating the
spruce budworm. Consequently its population goes
up and down with fluctuations in the populations
of the budworm. http//www.birds.cornell.edu/AllA
boutBirds/BirdGuide/Tennessee_Warbler_dtl.html
Probable rare breeder in Southeast Alaska,
accidental in central Alaska.
Armstrong. 1983. Birds of Alaska.
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castanea chestnut
Bay-breasted Warbler (Dendroica castanea) A
large warbler of the northern spruce forests, the
Bay-breasted Warbler benefits from spruce budworm
outbreaks when the caterpillars provide abundant
food. http//www.birds.cornell.edu/AllAboutBirds/
BirdGuide/Bay-breasted_Warbler_dtl.html
Accidental. Fairbanks.
Armstrong. 1983. Birds of Alaska.
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Data G. Juday
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spruce budworm damage
heat/drought limitation
BARK
Photo C. Alix
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Data G. Juday
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Data G. Juday
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Canadian Climate Center scenario
2004
recorded
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SUMMARY Spruce budworm is a major force
shaping the North American boreal forest.
Climate suitable for spruce budworm outbreaks
have generally not been present in boreal
Alaska until 1989. Seven stages of
development (L1 - L6, Pupa) over 2 years.
Winter cold temperatures do not appear to be a
limitation. Egg hatch, L1, to L2 must get
done in August, faster when warm. Greatest
amount of damage from L6 feeding. L2 to
adult must get done by mid-July (818 GDD F).
Light attacks reduce w. spruce radial
growth. Moderate attacks reduce growth and
height growth points. Repeated severe
attacks kill w. spruce. 3 boreal warblers
have been missing from Alaska breeding birds.
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PART 5. OK, SO WHAT HAPPENS NEXT?
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NE British Columbia We concluded that timber
losses are important in areas with maximum
defoliation. Ecological impacts involved
transformations of the forest that are likely
transitory, considering the time scale of
forestry (more than 100 years). Loss of
biodiversity habitat is particularly important in
areas that have been reserved for their
old-growth characteristics. However, a changing
climate may alter the long-term effects of
budworm on the forest. The current outbreak has
been longer and more severe than past outbreaks
for which we have historical or tree-ring
records. We cannot predict what these future
changes will be, but the forest may change in
different ways than it has in the past. The
spruce budworm may also begin to attack forests
where it has not been previously found.
Source Natural Resources Canada http//cfs.nrcan.
gc.ca/subsite/budworm/space-spatiale
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PROBABLE SPRUCE BUDWORM FUTURE IN ALASKA BOREAL
FOREST Large outbreaks continue, intensify,
and spread west, up, north W. spruce
experiences high mortality and becomes less
abundant Spruce budworm becomes limited by
lack of contiguous susceptible stands of w.
spruce W. spruce stabilizes population at
lower level and in refuge stands in response
to repeated outbreak cycles.
Reduction/bottleneck for old-growth dependent
species, esp. insectivorous migratory
birds. 3 warbler species establish breeding
populations in Alaska. W. spruce niche in
uplands is partially displaced by - black
spruce - Alaska birch - aspen -
lodgepole pine?
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From scenario projection to forecasting?
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From scenario projection to forecasting?