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.

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 Dynamics and Management of Rising Outbreak Spruce Budworm Populations

Forests ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 748 ◽  
Author(s):  
Jacques Régnière ◽  
Barry Cooke ◽  
Ariane Béchard ◽  
Alain Dupont ◽  
Pierre Therrien
Keyword(s):  
Population Growth ◽  
Density Dependence ◽  
Natural Enemies ◽  
Choristoneura Fumiferana ◽  
Regional Scale ◽  
Adult Emergence ◽  
Spruce Budworm ◽  
Migration Activity ◽  
Larval Stages ◽  
The Impact

Management of spruce budworm, Choristoneura fumiferana (Clem.), outbreak spread requires understanding the demographic processes occurring in low, but rising populations. For the first time, detailed observations were made in the early stages of outbreak development. We sampled populations over a three-year period in both treated and untreated populations in the Lower St-Lawrence region of Quebec, Canada, and measured the density-dependence of survival and population growth rates, and the impact of natural enemies and insecticides. Insecticides tested were Bacillus thuringiensis (Berliner 1915) and tebufenozide. We recorded strong density-dependence of survival between early larval stages and adult emergence, explained largely by the variation of natural enemy impacts and overcrowding. We also observed inverse density-dependence of apparent fecundity: net immigration into lower-density populations and net emigration from the higher, linked to a threshold of ~25% defoliation. Because of high migration rates, none of the 2013 treatments reduced egg populations at the end of summer. However lower migration activity in 2014 allowed population growth to be reduced in treated plots. This evidence lends support to the conclusion that, for a budworm population to increase to outbreak density, it must be elevated via external perturbations, such as immigration, above a threshold density of ~4 larvae per branch tip (L4). Once a population has increased beyond this threshold, it can continue growing and itself become a source of further spread by moth migration. These findings imply that populations can be brought down by insecticide applications to a density where mortality from natural enemies can keep the reduced population in check, barring subsequent immigration. While we recognize that other factors may occasionally cause a population to exceed the Allee threshold and reach outbreak level, the preponderance of immigration implies that if all potential sources of significant numbers of moths are reduced on a regional scale by insecticide applications, a widespread outbreak can be prevented, stopped or slowed down by reducing the supply of migrating moths.

BEHAVIOURAL EFFECTS OF SECONDARY COMPONENTS OF THE SEX PHEROMONE OF THE EASTERN SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (LEPIDOPTERA: TORTRICIDAE)

1983 ◽  
Vol 115 (9) ◽  
pp. 1053-1058 ◽  
Author(s):  
A. R. Alford ◽  
P. J. Silk ◽  
M. McClure ◽  
C. Gibson ◽  
J. Fitzpatrick
Keyword(s):  
Sex Pheromone ◽  
Wind Tunnel ◽  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Field Observations ◽  
Eastern Spruce Budworm ◽  
Behavioural Effects ◽  
Low Levels ◽  
Number Of Males

AbstractLaboratory wind tunnel and field observations have demonstrated an important behavioural role of tetradecanal (14:Ald) in the chemical communication system of the spruce budworm, Choristoneura fumiferana (Clemens). A greater number of males initiated upwind flight and continued on to contact the source when 14:Ald was present than with 95/5 E/Z11-tetradecenal (E/Z11-14:Ald) alone. The presence of E11-tetradecen-1-ol acetate (E11-14:Ac) decreased the males' responsiveness to the aldehydes. Its effect appeared to be attenuated, when present at low levels with 95/5 E/Z11-14:Ald, by the presence of 14:Ald, but it is still unclear what effects low levels of E11-14:Ac have on male behaviour.

ESTIMATED EGG DEPOSITION BY INVADING SPRUCE BUDWORM MOTHS (LEPIDOPTERA: TORTRICIDAE)

1978 ◽  
Vol 110 (6) ◽  
pp. 609-615 ◽  
Author(s):  
C. A. Miller ◽  
D. O. Greenbank ◽  
E. G. Kettela
Keyword(s):  
New Brunswick ◽  
Larval Stage ◽  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Light Traps ◽  
Minimum Level ◽  
Egg Deposition ◽  
Baited Traps ◽  
The Impact

AbstractA 4000-ha block of spruce budworm, Choristoneura fumiferana (Clem.), infested forest in western New Brunswick was sprayed repeatedly in 1975 during the larval stage of budworm development. The objective was to reduce the population of the 1975 generation to a minimum level so that most of the following generation eggs found on the block could be attributed to invading females, thus providing data on the impact of moth invasion.The presence of dispersing adults in the airspace over the block was monitored by a ground-based radar unit while light traps and pheromone-baited traps were used to confirm that invasion had taken place. A total egg population of 33.8 masses per m2 of foliage was found on the block and indirect estimates suggest that invading females deposited about 10 of these masses.

Impact de la tordeuse des bourgeons de l'épinette [Choristoneura fumiferana (Clem.)] sur la régénération des sapinières après la coupe à blanc

1993 ◽  
Vol 69 (2) ◽  
pp. 163-172 ◽  
Author(s):  
J.-C. Ruel ◽  
M. Huot
Keyword(s):  
Key Words ◽  
Choristoneura Fumiferana ◽  
Abies Balsamea ◽  
Spruce Budworm ◽  
Balsam Fir ◽  
Dominant Position ◽  
The Impact ◽  
Coupe À Blanc

An analysis of over 100 balsam fir [Abies balsamea (L.) Mill.] stands has shown some effects of spruce budworm defoliation on regeneration after clearcutting. Even though softwood stocking was consistently high prior to harvesting operations, longer infestation periods or more severe defoliation levels led to a decrease in the stocking of softwood stems above 50 cm height and to the establishment and development of hardwood advance growth. Hardwoods were more often in a dominant position in the most severely damaged stands and the budworm effect was still persistent on the regeneration structure even 5 years after logging. Cutovers with less than 60% stocking were also more frequent in the most severely devastated fir stands. This situation seemed directly related to the impact of the spruce budworm on balsam fir advance growth. Key words: balsam fir, Choristoneura fumiferana, advance growth, clearcutting

scholarly journals NOTES ON A SPRUCE BUDWORM INFESTATION IN BRITISH COLUMBIA

1960 ◽  
Vol 36 (4) ◽  
pp. 362-374 ◽  
Author(s):  
G. T. Silver
Keyword(s):  
British Columbia ◽  
Pseudotsuga Menziesii ◽  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Douglas Fir ◽  
Population Trends ◽  
Seasonal Development ◽  
Host Trees ◽  
One Year ◽  
The One

An outbreak of the one-year cycle spruce budworm, Choristoneura fumiferana (Clem.), on Douglas fir, Pseudotsuga menziesii (Mirb.) Franco, which lasted six years before collapsing, is described. Population trends and seasonal development, effect of defoliation on the host trees and parasites of the insect are discussed.

EXPOSING LARVAE OF THE SPRUCE BUDWORM (LEPIDOPTERA: TORTRICIDAE) TO SUBLETHAL DOSES OF BACILLUS THURINGIENSIS SUBSP. KURSTAKI DOES NOT AFFECT SURVIVAL DURING THE PUPAL STAGE

2000 ◽  
Vol 132 (3) ◽  
pp. 341-343 ◽  
Author(s):  
Kees van Frankenhuyzen ◽  
John Dedes
Keyword(s):  
Bacillus Thuringiensis ◽  
Choristoneura Fumiferana ◽  
Pupal Stage ◽  
Adult Emergence ◽  
Spruce Budworm ◽  
Larval Population ◽  
Immature Development ◽  
Sublethal Doses ◽  
Carry Over ◽  
The Impact

A process-oriented model was recently developed to simulate the efficacy of spray products containing Bacillus thuringiensis Berliner subsp. kurstaki (Bacillaceae) against the spruce budworm, Choristoneura fumiferana Clemens (Cooke and Régnière 1996). The model accurately predicted foliage protection and larval population reduction during validation spray trials (Régnière and Cooke 1998; Cooke and Régnière 1999). The impact of treatment on budworm generation survival was generally well mimicked by the model except for a consistent overestimation of survival at the end of immature development in the treated plots. Régnière and Cooke (1998) speculated that residual mortality due to treatment may be occurring during the pupal stage. Carry-over of B. thuringiensis from larvae to pupae has been documented for spruce budworm (Klein and Lewis 1966) and several other Lepidoptera (Legner and Oatman 1962; Angus 1965). Although we recently investigated the response of spruce budworm larvae to ingestion of sublethal doses of B. thuringiensis (Pedersen et al. 1997), effects on pupal survival or adult emergence were not examined. In this note, we report the results of an experiment designed to assess such effects.

Les forêts de la Côte Nord au Québec sont-elles sujettes aux déprédations par la tordeuse?

1983 ◽  
Vol 59 (1) ◽  
pp. 17-20 ◽  
Author(s):  
J. Robert Blais
Keyword(s):  
Tree Mortality ◽  
Growth Ring ◽  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Balsam Fir ◽  
North Shore ◽  
The North ◽  
River Region ◽  
Saguenay River ◽  
The Impact

Quebec's North Shore is a vast region comprising about one third of productive forests in the province. The impact of the spruce budworm (Choristoneura fumiferana (Clem.)) in this remote region was not welt known. In the summer of 1981, ground and aerial surveys were conducted to determine the extent to which fir stands had been affected during the current bud-worm outbreak. It was possible to confirm that defoliation had been severe for several successive years prior to 1978, and that since then, insect populations had diminished considerably. Available information on balsam fir mortality indicated only two areas: one in Saguenay River region in the extreme southwest of the study area, and the other in the vicinity of Baie Comeau. The 1981 surveys revealed that varying quantities of fir had succumbed to budworm attack in many stands occurring for hundreds of kilometers east of Baie Comeau. The spruce budworm maintained high populations sufficiently long to cause pockets of tree mortality over a widespread area on the North Shore. Growth-ring measurements on several old balsam fir and white spruce trees from many localities indicated that no other widespread budworm outbreak had occurred on the North Shore since the end of the nineteenth century.

scholarly journals Avian Predation in a Declining Outbreak Population of the Spruce Budworm, Choristoneura fumiferana (Lepidoptera: Tortricidae)

Insects ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 720
Author(s):  
Jacques Régnière ◽  
Lisa Venier ◽  
Dan Welsh
Keyword(s):  
Foraging Behavior ◽  
Picea Glauca ◽  
Choristoneura Fumiferana ◽  
Feeding Activity ◽  
Abies Balsamea ◽  
Bird Species ◽  
Spruce Budworm ◽  
White Spruce ◽  
Avian Predation ◽  
The Impact

The impact of avian predation on a declining population of the spruce budworm, Choristoneura fumifereana (Clem.), was measured using single-tree exclosure cages in a mature stand of balsam fir, Abies balsamea (L.), and white spruce, Picea glauca (Moench.) Voss. Bird population censuses and observations of foraging and nest-feeding activity were also made to determine the response of budworm-linked warblers to decreasing food availability. Seasonal patterns of foraging. as well as foraging success in the declining prey population was compared to similar information from birds observed in another stand where the spruce budworm population was rising. Avian predation was an important source of mortality between the 4th instar and moth emergence in the declining outbreak population. Mortality by predation increased from negligible to over 98% as budworm density dropped from 100 to <1 larva/kg of host foliage, over 3 years. Calculations based on nest-feeding activity and basic metabolic demands support these observed rates. Seasonal and yearly differences in predation rates observed between the two host-tree species correspond to equivalent shifts in bird foraging behavior in response to dropping insect density. In particular, a preference for searching on white spruce disappeared, although budworm-linked birds remained more efficient at finding food on this plant. The ability to change foraging behavior as prey density dropped differed between bird species.

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