Périodicité et synchronisme des épidémies de la tordeuse des bourgeons de l'épinette au Québec

2003 ◽  
Vol 33 (10) ◽  
pp. 1947-1961 ◽  
Author(s):  
Yves Jardon ◽  
Hubert Morin ◽  
Pierre Dutilleul
Keyword(s):  
Population Dynamics ◽  
Choristoneura Fumiferana ◽  
Local Population ◽  
Spruce Budworm ◽  
Periodic Component ◽  
Moran Effect ◽  
Regional Effect ◽  
Migration Effect ◽  
Different Types ◽  
Insect Populations

A time series analysis was performed on 32 dendrochronological chronologies using Dutilleul's multi frequential periodo gram. Our aim was to estimate the periodicities of spruce budworm (Choristoneura fumiferana (Clem.)) outbreaks in the province of Quebec. Our analysis estimated a signal of 25-38 years corresponding to spruce budworm outbreaks. Analyses conducted in the 20th century indicated the existence of true periodicities in half of the series suggesting local population dynamics. These periodicities were estimated to be 29-34 years. For the other series, outbreaks were explained by the addition of a second periodic component to the fundamental periodicity. These combined periodicities (pseudoperiodicities or complex periodicities) described most of the 130-year series analysed. The lack of several outbreaks explained part of the combined periodicity. The results suggest a migration effect and complex local population dynamics. A third periodic component explains the double epidemic waves. These estimated periodicities are often similar and in phase. We believe that a common regional effect (the Moran effect) acts on the minor fluctuations of the insect populations and helps synchronize the outbreaks. This research shows that different types of outbreak dynamics can be found within a same insect species.

A METHOD FOR REARING THE LARVAL STAGES OF THE EASTERN SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA CLEMENS (LEPIDOPTERA: TORTRICIDAE), FOR PHYSIOLOGICAL STUDIES

1990 ◽  
Vol 122 (6) ◽  
pp. 1271-1272 ◽  
Author(s):  
Hemendra Mulye ◽  
Roger Gordon
Keyword(s):  
Population Dynamics ◽  
North America ◽  
Choristoneura Fumiferana ◽  
Insect Pest ◽  
Spruce Budworm ◽  
Forest Pest ◽  
Forest Insect ◽  
Larval Stages ◽  
Eastern Spruce Budworm ◽  
Physiological Studies

The eastern spruce budworm, Choristoneura fumiferana Clemens, is the most widely distributed and destructive forest insect pest in North America. Although much is known about the ecology, population dynamics, and impact of C. fumiferana on tree growth (Sanders et al. 1985), there is very little information available on the physiology of this forest pest. Physiological studies are crucial to the development of novel strategies for spruce budworm control.

Digestion of Spruce Budworm Larvae and Pupae in the Olive-backed Thrush, Hylochichla ustulata swainsoni (Tschudi)

1965 ◽  
Vol 97 (11) ◽  
pp. 1144-1149 ◽  
Author(s):  
L. J. Mook ◽  
H. G. W. Marshall
Keyword(s):  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Bird Predation ◽  
Digestion Rate ◽  
Insect Populations

AbstractTo use gizzard analysis quantitatively, in the assessment of bird predation on insect populations, information is needed on the time that identifiable remains of the prey can be found in the gizzard and on the rate at which these remains disappear. The digestion rate, measured by the disappearance of mandibles or cremasters, has been studied for larvae and pupae of the spruce budworm, Choristoneura fumiferana (Clem.), when eaten by the olive-backed thrush, Hylocichla ustulata swainsoni (Tschudi).

RESPONSE OF THIRD-, FOURTH-, FIFTH-, AND SIXTH-INSTAR SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (CLEM.), LARVAE TO NUCLEAR POLYHEDROSIS VIRUS

1990 ◽  
Vol 122 (5) ◽  
pp. 1037-1038 ◽  
Author(s):  
W.J. Kaupp ◽  
P.M. Ebling
Keyword(s):  
Nuclear Polyhedrosis Virus ◽  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Control Agent ◽  
Efficacy Trials ◽  
Eastern Spruce Budworm ◽  
Different Types ◽  
Polyhedrosis Virus ◽  
Nuclear Polyhedrosis ◽  
Feeding Techniques

Four different types of insect viruses have been isolated from the eastern spruce budworm, Choristoneura fumiferana (Clem.), but most research efforts have been concentrated on developing the nuclear polyhedrosis virus (NPV) as a viable control agent (Cunningham 1985). There are no published reports of LD50 values for this important forest pest. Recently, a LC50 of 483 viral polyhedra per square millimetre of diet surface for fifth-instar budworm larvae was determined using surface contamination feeding techniques (Cunningham et al. 1983). Because the dosages used in efficacy trials are derived from laboratory LD50 values, experiments were conducted to determine the virulence of this NPV to eastern spruce budworm. Bioassays were conducted with all feeding instars. Reported here are values for the LD50 dosages for third-, fourth-, fifth-, and sixth-instar spruce budworm larvae.

A GEOGRAPHICAL CLINE IN EGG WEIGHTS IN CHORISTONEURA FUMIFERANA (LEPIDOPTERA: TORTRICIDAE) AND ITS SIGNIFICANCE IN POPULATION DYNAMICS

1983 ◽  
Vol 115 (9) ◽  
pp. 1103-1108 ◽  
Author(s):  
G. T. Harvey
Keyword(s):  
Population Dynamics ◽  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Pupal Weight ◽  
Egg Weight ◽  
Winter Conditions ◽  
The Mean

AbstractThe mean weights of the initial eggs (Ei) of the spruce budworm, Choristoneura fumiferana (Clem.), vary within and between populations. Measurements of collections from across the range of this species reveal the presence of a cline directly related to latitude and longitude of the collection source. Collection mean Ei values range from 0.219 mg in the northwest to 0.157 mg in the southeast. A similar cline, also related to latitude but negative in slope, is demonstrated for the number of eggs per unit pupal weight. This cline also finds expression in changing slope of fecundity/pupal weight regressions. The cline in egg weight appears to be an adaptation to winter conditions across the range of this insect and should be considered in population dynamics.

scholarly journals Quantifying and predicting population connectivity of an outbreaking forest insect pest

2021 ◽  
Author(s):  
Jeremy Larroque ◽  
Julian Wittische ◽  
Patrick M. A. James
Keyword(s):  
Population Dynamics ◽  
Landscape Connectivity ◽  
Choristoneura Fumiferana ◽  
Insect Pest ◽  
Management Strategies ◽  
Temporal Stability ◽  
Spruce Budworm ◽  
Population Connectivity ◽  
Outbreak Area ◽  
Future Landscape

Abstract Context Dispersal has a key role in the population dynamics of outbreaking species such as the spruce budworm (Choristoneura fumiferana) as it can synchronize the demography of distant populations and favor the transition from endemic to epidemic states. However, we know very little about how landscape structure influences dispersal in such systems while such knowledge is essential for better forecasting of spatially synchronous population dynamics and to guide management strategies. Objectives We aimed to characterize the spatial environmental determinants of spruce budworm dispersal to determine how these features affect outbreak spread in Quebec (Canada). We then apply our findings to predict expected future landscape connectivity and explore its potential consequences on future outbreaks. Methods We used a machine-learning landscape genetics approach on 447 larvae covering most of the outbreak area and genotyped at 3562 SNP loci to identify the main variables affecting connectivity. Results We found that the connectivity between outbreak populations was driven by the combination of precipitation and host cover. Our forecasting suggests that between the current and next outbreaks, connectivity may increase between Ontario and Quebec, and might decrease in the eastern part, which could have the effect of limiting outbreak spread from Ontario and Quebec to the eastern provinces. Conclusions Although we did not identify any discrete barriers, low connectivity areas might constrain dispersal in the current and future outbreaks and should in turn, be intensively monitored. However, continued sampling as the outbreak progresses is needed to confirm the temporal stability of the observed patterns.

scholarly journals Bottom-up factors contribute to large-scale synchrony in spruce budworm populations

2018 ◽  
Vol 48 (3) ◽  
pp. 277-284 ◽  
Author(s):  
Mathieu Bouchard ◽  
Jacques Régnière ◽  
Pierre Therrien
Keyword(s):  
Large Scale ◽  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Trophic Factors ◽  
Population Fluctuations ◽  
Bottom Up ◽  
Cone Production ◽  
Climate Change Effects ◽  
Phenological Mismatch ◽  
Insect Populations

Understanding the mechanisms that cause large-scale synchrony in insect population dynamics might yield key insights for predicting potential outbreak occurrence. Here, we evaluated which environmental factors best explain synchronous population fluctuations in the spruce budworm (Choristoneura fumiferana Clem.) (SBW), a major defoliator of coniferous forests in North America. SBW population levels were assessed with pheromone traps during the 1986–2014 period across a 625 000 km2 territory located in the province of Québec (Canada). The populations were characterized by abundance fluctuations that were often synchronized across the whole study area. Interannual population fluctuations were correlated with host tree cone production (a source of food) and high May temperatures, suggesting that synchrony was influenced by food availability and phenological mismatch during shoot development. Cone production was itself correlated with low precipitation during the previous summer. This study indicates that bottom-up trophic factors can drive spatiotemporal synchrony in insect populations and contribute to explain important and sustained population increases during some years. We also suggest that several biological processes, all influenced by weather, are likely to interact to explain population synchrony during the different phases of the approximately 35 year SBW outbreak cycle, complicating the prediction of climate change effects on this insect.

Multidirectional War and Paramilitarism

2018 ◽  
Author(s):  
Tomas Balkelis
Keyword(s):  
National Identity ◽  
Local Level ◽  
Local Population ◽  
Cycle Of Violence ◽  
Different Types ◽  
The Masses ◽  
Socially Motivated

This chapter, by following the course of military actions in Lithuania in 1919, explores the emergence of various military and paramilitary groups that engaged in different types of violence. The focus here is on the entanglement of three types of actors: those that performed state-sanctioned violence; those that acted as semi-independent paramilitary agents, and those that engaged in ethnically or socially motivated violence on a local level. The ability of the Lithuanian government to survive the series of military engagements in 1919 enhanced its legitimacy among the local population, and laid the foundation for a modern Lithuanian identity among the masses. Yet the new state and national identity were shaped in a continuous cycle of violence, social strife, mobilization, and militarization of society.

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.

Sign in / Sign up

Export Citation Format

Share Document