scholarly journals Modeling Climatic Influences on Three Parasitoids of Low-Density Spruce Budworm Populations. Part 1: Tranosema rostrale (Hymenoptera: Ichneumonidae)

Forests ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 846
Author(s):  
Jacques Régnière ◽  
M. Lukas Seehausen ◽  
Véronique Martel
Keyword(s):  
Choristoneura Fumiferana ◽  
Seasonal Pattern ◽  
Spruce Budworm ◽  
Choristoneura Rosaceana ◽  
Mortality Factors ◽  
Alternate Host ◽  
Temperature Dependent ◽  
Complex Interactions ◽  
Adult Parasitoid ◽  
Spatial Differences

Despite their importance as mortality factors of many insects, the detailed biology and ecology of parasitoids often remain unknown. To gain insights into the spatiotemporal biology of insect parasitoids in interaction with their hosts, modeling of temperature-dependent development, reproduction, and survival is a powerful tool. In this first article of a series of three, we modeled the biology of Tranosema rostrale at the seasonal level with a three-species individual-based model that took into account the temperature-dependent performance of the parasitoid and two of its hosts. The predicted activity of the first adult parasitoid generation closely matched the seasonal pattern of attack on the spruce budworm, Choristoneura fumiferana (Lepidoptera: Tortricidae). The model predicted 1–4 full generations of T. rostrale per year in eastern North America. The generations were generally well synchronized with the occurrence of larvae of a probable alternate host, the obliquebanded leafroller Choristoneura rosaceana (Lepidoptera: Tortricidae), which could be used as an overwintering host. Spatial differences in predicted performance were caused by complex interactions of life-history traits and synchrony with the overwintering host, which led to a better overall performance in environments at higher elevations or along the coasts. Under a climate warming scenario, regions of higher T. rostrale performance were predicted to generally move northward, making especially lower elevations in the southern range less suitable.

scholarly journals Modeling Climatic Influences on Three Parasitoids of Low-Density Spruce Budworm Populations. Part 2: Meteorus trachynotus (Hymenoptera: Braconidae)

Forests ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 155
Author(s):  
Jacques Régnière ◽  
Rémi Saint-Amant ◽  
Jean-Claude Thireau ◽  
Pierre Therrien ◽  
Christian Hébert ◽  
...  
Keyword(s):  
Choristoneura Fumiferana ◽  
Seasonal Pattern ◽  
Spruce Budworm ◽  
Seasonal Development ◽  
Choristoneura Rosaceana ◽  
Field Observations ◽  
Seasonal Interactions ◽  
Northern Portion ◽  
Response To Temperature ◽  
The Impact

This is the second article of a series of three where we develop temperature-driven models to describe the seasonal interactions between parasitoids and their hosts which we use to explore the impact of climate on their spatiotemporal biology. Here, we model the biology of Meteorus trachynotus (Hymenoptera: Braconidae) with an individual-based model of its daily interactions with two host species. This model predicts the performance of the parasitoid in response to temperature affecting its seasonal development and that of the two hosts. We compare model output with an extensive set of field observations from natural host populations. The predicted activity of the first adult parasitoid generation closely matches the seasonal pattern of attack on the spruce budworm, Choristoneura fumiferana (Lepidoptera: Tortricidae) within the limitations of available data. The model predicts 1–4 full generations of M. trachynotus per year in eastern North America, with generations well synchronized with larvae of a known overwintering host, the obliquebanded leafroller Choristoneura rosaceana. The model predicts the observed density dependence of parasitism on spruce budworm. Predicted performance exhibits spatial variation caused by complex life-history interactions, especially synchrony with the overwintering host. This leads to a better performance in warm but not hot environments at middle latitudes and elevations. The model’s predicted spatial patterns correspond closely to our field observations on the frequency of parasitism on spruce budworm. Under climate change, the model predicts that the performance of M. trachynotus populations will improve in the northern portion of its range.

WEATHER AND THE ECOLOGY OF APANTELES FUMIFERANAE VIER. (HYMENOPTERA: BRACONIDAE)

1988 ◽  
Vol 120 (S146) ◽  
pp. 57-70 ◽  
Author(s):  
Vincent G. Nealis
Keyword(s):  
Field Data ◽  
Historical Data ◽  
Spruce Budworm ◽  
Temperature Dependent ◽  
Maturation Period ◽  
Phenological Model ◽  
Model Based ◽  
Egg Maturation ◽  
Adult Parasitoid ◽  
Specific Mortality

AbstractThe effects of weather on the spruce budworm parasitoid, Apanteles fumiferanae Vier., are examined. A phenological model based on temperature-dependent rates of development and longevity is developed and validated with field data. The model is then used to explore the effects of age-specific mortality on phenological behaviour of the parasitoid and the seasonal synchrony between the parasitoid and its host over several years. The results show that the parasitoid adult ecloses well before the host reaches an age susceptible to parasitism but that the egg maturation period and the longevity of the parasitoid diminish the consequences of the apparent asynchrony. The historical data reveal that the relative phenological characteristics of A. fumiferanae and its host vary little from year to year. In the second part of the study, temperature is shown to have a strong effect on adult parasitoid activity and on the rate of oviposition.

LIFE HISTORY CHARACTERISTICS OF ELACHERTUS CACOECIAE (HYMENOPTERA: EULOPHIDAE), AN ECTOPARASITOID OF SPRUCE BUDWOR LARVAE, CHORISTONEURA FUMIFERANA (LEPIDOPTERA: TORTRICIDAE)

1998 ◽  
Vol 130 (2) ◽  
pp. 215-229 ◽  
Author(s):  
Jeffrey G. Fidgen ◽  
Eldon S. Eveleigh
Keyword(s):  
Choristoneura Fumiferana ◽  
Abies Balsamea ◽  
Pupal Stage ◽  
Spruce Budworm ◽  
Oviposition Period ◽  
Host Feeding ◽  
Adult Males ◽  
Alternate Host ◽  
Laboratory Development ◽  
The Mean

AbstractWe carried out a 2-year study to elucidate the biology of the gregarious, idiobiont ectoparasitoid Elachertus cacoeciae (Howard) by placing (implanting) laboratory-reared spruce budworm larvae [Choristoneura fumiferana (Clemens)] on current-year balsam fir (Abies balsamea L.) shoots in the field, simulating low (endemic) densities of the budworm. Spring female E. cacoeciae attacked fourth-, fifth-, and sixth-instar budworm larvae, beginning near the predicted peak of the fourth instar and ending about 10–12 days after the predicted peak of the pupal stage of the wild budworm population. The mean (±SE) brood size of spring females was 2.9 ± 0.3 E. cacoeciae pupae per host. The proportion of females increased during the season, with many broods consisting of 100% females late in the season. In 1994 and 1995, the mean proportion of females was 0.74 ± 0.05 and 0.79 ± 0.05, respectively. In the laboratory, development time from eggs to adults was approximately 20 days at 20.6 °C. Adult males provided with honey water lived 43.6 ± 3.2 days, whereas females provided with hosts and honey water lived 90.1 ± 6.6 days. Spring females had a pre-oviposition period of 11.5 ± 1.3 days, resulting in a generation time (egg to egg) of ~31 days. The oviposition period lasted 76.3 ± 7.7 days during which time spring females parasitized 19.2 ± 1.9 hosts, and produced a clutch size of 4.9 ± 0.4 eggs per host, for a lifetime fecundity of 96.8 ± 14.7 eggs. The post-oviposition period was 18.5 ± 3.7 days. Throughout their lifetime, spring females host fed only (host feeding without oviposition) on an additional 9.3 ± 1.9 hosts. Approximately 2% of pupae developing from spring females overwintered, whereas approximately 95% of pupae developing from summer females overwintered. Laboratory results for summer females suggest that they may be adapted to parasitizing alternate host(s) rather than spruce budworm.

INTERACTIONS BETWEEN BACILLUS THURINGIENSIS BERLINER AND APANTELES FUMIFERANAE VIER. (HYMENOPTERA: BRACONIDAE), A PARASITOID OF THE SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (CLEM.) (LEPIDOPTERA: TORTRICIDAE)

1990 ◽  
Vol 122 (4) ◽  
pp. 585-594 ◽  
Author(s):  
Vincent Nealis ◽  
Kees van Frankenhuyzen
Keyword(s):  
Bacillus Thuringiensis ◽  
Negative Impact ◽  
Choristoneura Fumiferana ◽  
Management Strategies ◽  
Lethal Dose ◽  
Spruce Budworm ◽  
Fourth Instar ◽  
Mortality Factors ◽  
Commercial Formulation ◽  
Beneficial Effects

AbstractInteractions between Bacillus thuringiensis Berliner and Apanteles fumiferanae Viereck as mortality factors of the spruce budworm, Choristoneura fumiferana (Clemens), were investigated by placing parasitized and nonparasitized budworm larvae on foliage with and without spray deposits of a commercial formulation of B. thuringiensis. The effect of larval age (and, thus, the timing of spray applications) was examined by using peak third-instar and peak fourth-instar larvae. We demonstrated that parasitized larvae are more likely to survive exposure to B. thuringiensis because they feed less than non-parasitized larvae and are thus less likely to acquire a lethal dose of the bacterium. Bacillus thuringiensis nevertheless reduced parasitoid populations by 50–60% by killing their hosts before parasitoid emergence. This negative impact of B. thuringiensis on parasitoid survival was decreased when exposure of budworm larvae to spray deposits was delayed from peak third to peak fourth instar. The enhanced survival of parasitoids offset the lower mortality as a result of B. thuringiensis in the delayed sprays. We conclude that B. thuringiensis applied when budworm larval populations are at peak fourth instar or later would complement rather than interfere with the beneficial effects of A. fumiferanae. The implications for budworm management strategies are discussed.

The Interaction of the Spruce Budworm, Choristoneura fumiferana (Clem.), and the Parasite Apanteles fumiferanae Vier.

1959 ◽  
Vol 91 (8) ◽  
pp. 457-477 ◽  
Author(s):  
C. A. Miller
Keyword(s):  
New Brunswick ◽  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Forest Pest ◽  
Mortality Factors ◽  
Term Study ◽  
Green River ◽  
Long Term Study ◽  
The Subject

In the late 1940's significant increases in the population of the spruce budworm, worm, Choristoneura fumiferana (Clem.), occurred in northern New Brunswick and culminated in a severe outbreak of this major forest pest. The outbreak has been the subject of intensive investigations dealing with emergency chemical control operations (Webb, 1956) and with a long-term study of the population dynamics of the budworm. The latter program, called the Green River Project, is located on the Green River Watershed in northwestern New Brunswick. Its objectives, the co-operating agencies involved, the mortality factors being studied, and methodology have been discussed elsewhere by Morris et al. (1956), Morris (1951), Morris and Miller (1954), and Morris (1955).

EFFECT OF TEMPERATURE AND EXPOSURE TIME ON TOXICITY OF BACILLUS THURINGIENSIS BERLINER SPRAY DEPOSITS TO SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA CLEMENS (LEPIDOPTERA: TORTRICIDAE)

1990 ◽  
Vol 122 (1) ◽  
pp. 69-75 ◽  
Author(s):  
Kees van Frankenhuyzen
Keyword(s):  
Bacillus Thuringiensis ◽  
Exposure Time ◽  
Choristoneura Fumiferana ◽  
Larval Mortality ◽  
Lethal Dose ◽  
Spruce Budworm ◽  
Fold Increase ◽  
Effect Of Temperature ◽  
Temperature Dependent ◽  
Limited Effect

AbstractExperiments were conducted using balsam fir twigs treated with Bacillus thuringiensis Berliner to examine the influence of temperature and exposure time on mortality of spruce budworm, Choristoneura fumiferana Clemens. Twigs were sprayed with a commercial formulation (8.4 BIU/L) using droplets of 40–70 μm diameter at densities, ranging from 0.5 to 5.5 droplets per needle. Temperature affected progression but not the level of cumulative mortality during 14 days of feeding on sprayed foliage. The LT50 decreased from 12–17 days at 13°C to 2–4 days at 25°C, depending on droplet density. Temperature between 13 and 25°C had a limited effect on dose acquisition because 40–60% of the larvae were able to acquire a lethal dose within 1 day of feeding on foliage with 0.5–1.5 droplets per needle, regardless of temperature. Under these conditions dose acquisition was not limited by temperature-dependent consumption of foliage, but rather by feeding inhibition associated with the dose initially ingested. This also limited the influence of exposure time; a 7- or 14-fold increase in exposure time increased larval mortality at most by 25%. Implications of these findings for improving efficacy of B. thuringiensis in forestry applications are discussed.

Derivation of Pheromone-Based Larval Thresholds in Spruce Budworm Accounting for Distance to Defoliated Forest Stands

2021 ◽  
Author(s):  
Marc Rhainds ◽  
Ian DeMerchant ◽  
Pierre Therrien
Keyword(s):  
Boreal Forests ◽  
Large Scale ◽  
Choristoneura Fumiferana ◽  
Intervention Strategy ◽  
Spruce Budworm ◽  
Interactive Effects ◽  
The Novel ◽  
Forest Stands ◽  
General Guideline ◽  
Number Of Males

Abstract Spruce budworm, Choristoneura fumiferana Clem. (Lepidoptera: Tortricidae), is the most severe defoliator of Pinaceae in Nearctic boreal forests. Three tools widely used to guide large-scale management decisions (year-to-year defoliation maps; density of overwintering second instars [L2]; number of males at pheromone traps) were integrated to derive pheromone-based thresholds corresponding to specific intergenerational transitions in larval densities (L2i → L2i+1), taking into account the novel finding that threshold estimates decline with distance to defoliated forest stands (DIST). Estimates of thresholds were highly variable between years, both numerically and in terms of interactive effects of L2i and DIST, which limit their heuristic value. In the context of early intervention strategy (L2i+1 > 6.5 individuals per branch), however, thresholds fluctuated within relatively narrow intervals across wide ranges of L2i and DIST, and values of 40–200 males per trap may thus be used as general guideline.

Weather and Outbreaks of the Spruce Budworm in the Province of Quebec from 1939 to 1956

1961 ◽  
Vol 93 (2) ◽  
pp. 118-123 ◽  
Author(s):  
J. G. Pilon ◽  
J. R. Blais
Keyword(s):  
Choristoneura Fumiferana ◽  
Abies Balsamea ◽  
Spruce Budworm ◽  
Balsam Fir ◽  
The Past ◽  
Forest Regions ◽  
Tree Component ◽  
Gaspe Peninsula ◽  
Gaspé Peninsula

Nearly all forest regions in the Province of Quebec where balsam fir (Abies balsamea (L.) Mill.) is an important tree component have been subjected to severe defoliation by the spruce budworm, Choristoneura fumiferana (Clem.), during the past 20 years. These outbreaks have followed an easterly direction beginning near the Ontario-Quebec border in 1939 and ending in the Gaspé Peninsula in 1958.

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