THE OCCURRENCE AND NATURE OF DIAPAUSE-FREE DEVELOPMENT IN THE SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (CLEM.) (LEPIDOPTERA: TORTRICIDAE)

1957 ◽  
Vol 35 (4) ◽  
pp. 549-572 ◽  
Author(s):  
George T. Harvey
Keyword(s):  
Environmental Conditions ◽  
Behavior Pattern ◽  
Choristoneura Fumiferana ◽  
Continuous Light ◽  
Spruce Budworm ◽  
Light Treatment ◽  
Complex Behavior ◽  
Eastern Canada ◽  
First Instar ◽  
Free Development

Spruce budworm populations in Eastern Canada are effectively univoltine. After hatching, the larva follows a complex behavior pattern that leads to the building of a hibernaculum in which it molts and spends the winter months without feeding. This pattern seems to be independent of environmental conditions, except as they affect the rate at which the component events occur, and, in the absence of any evidence to the contrary, must be considered as inherent.Laboratory studies have shown that in 62% of the families produced by matings of field-collected individuals at least one larva can develop without diapause if subjected to long photoperiods (at 71° F.); on the average 3 to 4% of the second-instar larvae in such progenies can forego diapause. Selection over six generations yielded a strain that, if subjected to continuous light in the laboratory, is virtually free from diapause. This stock has been reared for a further six generations and still retains this photoperiod dependence. Behavior is usually normal during hibernaculum construction and molting, but then the larvae vacate their shelters, feed readily, and develop without any delay. No associated differences have yet been found between non-diapause (N-D) and normal (D) insects. The ability to develop without diapause is apparently determined by multiple genes; it is not sex-linked but may be to some extent sex-controlled.Diapause-free development in this strain results only when first-instar larvae are exposed to a photoperiod of at least 15 hours, shorter times resulting in almost universal diapause and longer times giving a progressively greater proportion of N-D insects, approaching 100% in continuous light. This response is reduced by lower temperatures. Potential N-D insects deprived of a light-treatment behave as normal D insects; under appropriate conditions of light their progeny in turn develop without diapause.

STUDIES ON DIPTEROUS PARASITES OF THE SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (CLEM.) (LEPIDOPTERA.TORTRICIDAE): VI. PHOROCERA INCRASSATA SMITH (DIPTERA:TACHINIDAE)

1958 ◽  
Vol 36 (4) ◽  
pp. 453-462 ◽  
Author(s):  
H. C. Coppel
Keyword(s):  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Immature Stages ◽  
Eastern Canada ◽  
First Instar

Phorocera incrassala Smith, which was transferred from Western to Eastern Canada for release against the spruce budworm, Choristoneura fumiferana (Clem.), deposits microtype eggs on leaves, which are later ingested by the host. Eggs hatch immediately after ingestion, but the parasite does not develop beyond the first instar until the host pupates. The larva then develops rapidly, matures in 10 days, and forms its puparium within the host pupal case. The adult emerges in 12 to 14 days. No information is available on the overwintering habits. Among the important characters for identifying the immature stages of P. incrassala are the buccopharyngeal apparatus and the anterior and posterior spiracles.

Second Diapause in Spruce Budworm from Eastern Canada

1961 ◽  
Vol 93 (7) ◽  
pp. 594-602 ◽  
Author(s):  
George T. Harvey
Keyword(s):  
British Columbia ◽  
Experimental Analysis ◽  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Fourth Instar ◽  
Eastern Canada ◽  
Low Incidence ◽  
One Year ◽  
Storage Times ◽  
Second Period

In eastern Canada larvae of the spruce budworm, Choristoneura fumiferana (Clem.), complete their development in one year, undergoing only one period of winter diapause in the second instar, whereas in certain parts of British Columbia, at high altitudes, two years are normally required for development, the larvae spending a second period of winter diapause in the fourth instar (3, 9). Among laboratory-reared eastern budworm there are a few individuals that enter a similar second diapause (7). The low incidence and somewhat irregular occurrence of this second diapause in eastern budworm, even in laboratory rearings, have hitherto made detailed studies almost impossible, but unusual storage times and treatments used recently in rearing experiments had the unexpected effect of increasing the incidence of this tvpe of behaviour to a level where experimental analysis became possible. This paper describes these larvae and their behaviour; an account of the effects of various conditions upon the incidence of second diapause will be presented later.

THE EFFECT OF A MICROSPORIDIAN PARASITE ON THE DEVELOPMENT, REPRODUCTION, AND MORTALITY OF THE SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (CLEM.)

1958 ◽  
Vol 36 (4) ◽  
pp. 499-511 ◽  
Author(s):  
H. M. Thomson
Keyword(s):  
Initial Dose ◽  
Male Fertility ◽  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Malpighian Tubules ◽  
Pupal Weight ◽  
Adult Longevity ◽  
Microsporidian Parasite ◽  
Pupal Development ◽  
First Instar

Infection of the spruce budworm, Choristoneura fumiferana (Clem.), by the microsporidian parasite Perezia fumiferanae Thorn, retards both larval and pupal development and reduces pupal weight, fecundity, and adult longevity. These effects are more pronounced among the female insects. There is no evidence that the parasite affects male fertility, mate choice, or the fertility of eggs produced. The parasite causes some mortality, most of which occurs before the fifth instar. Among larvae infected orally, mortality seems to be related to the size of the initial dose. Mortality occurs equally in both sexes. The development and survival of the first instar and overwintering second instar are not affected by the parasite. It is suggested that the parasite causes most of the observed results by reducing the insect's ability to assimilate its food. Mortality, however, is believed to be due to the destruction of the mid-gut or Malpighian tubules.

Effects of Spruce Budworm Outbreaks on the Productivity and Stability of Balsam Fir Forests

1984 ◽  
Vol 60 (5) ◽  
pp. 273-279 ◽  
Author(s):  
David A. MacLean
Keyword(s):  
Tree Mortality ◽  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Balsam Fir ◽  
Wood Production ◽  
Ecological Stability ◽  
Short Term ◽  
Eastern Canada ◽  
Feasible Method ◽  
Human Usage

Effects of spruce budworm (Choristoneura fumiferana (Clem.)) outbreaks on the productivity and stability of forests in eastern Canada are reviewed and discussed. Defoliation results in reduced growth of trees, widespread tree mortality, and loss of wood production, and thereby causes major forest management problems. At present, the only feasible method for limiting damage and losses from budworm outbreaks over large areas is to apply chemical or biological insecticides periodically to kill larvae and protect the forest from defoliation and tree mortality. Although budworm outbreaks definitely disrupt the wood-producing capacity of forests (or the short-term "stability of forests for human usage"), in terms of overall ecological stability, outbreaks apparently act as a cycling mechanism that allows advance fir-spruce regeneration to succeed the fir-spruce overstory.

The influence of forest composition and climate on outbreak characteristics of the spruce budworm in eastern Canada

2013 ◽  
Vol 43 (12) ◽  
pp. 1181-1195 ◽  
Author(s):  
David R. Gray
Keyword(s):  
Black Spruce ◽  
Choristoneura Fumiferana ◽  
Basal Area ◽  
Spruce Budworm ◽  
Climate Scenario ◽  
Forest Composition ◽  
Eastern Canada ◽  
The North ◽  
Average Change ◽  
Maximum Temperatures

The spruce budworm (Choristoneura fumiferana Clemens) is perhaps the single most important disturbance agent in Canada’s eastern forests. Climate and forest composition are dominant factors in spruce budworm outbreak dynamics through their direct influences on the pest, its natural enemies, and its hosts, and through their influence on the multitrophic interactions that are important in outbreak dynamics. A combination of four climate variables, three forest composition variables, and one location variable explained 60% of the multivariate variability in outbreak characteristics (duration and severity) in eastern Canada. Outbreak duration was most strongly influenced by April–May accumulation of degree-days; outbreak severity was most strongly influenced by the extreme maximum temperatures of April–May. The basal area of balsam fir had a stronger influence than that of black spruce on duration and on severity. Both outbreak characteristics declined in more northerly locations. Under a projected future (2011–2040) climate scenario the largest increases in outbreak duration and severity are predicted to occur on the Gaspé Peninsula and the north shore of the St. Lawrence River (Quebec). The largest decreases in duration and severity are predicted to occur in southern Ontario and along the Bay of Fundy in New Brunswick and Nova Scotia. The predicted average change in outbreak duration is around –1.3 years. The predicted average change in outbreak severity is only slightly different from zero (around –1.5% defoliation).

SUSCEPTIBILITY OF EARLY INSTARS OF SPRUCE BUDWORM (LEPIDOPTERA: TORTRICIDAE) TO HETERORHABDITIS HELIOTHIDIS (NEMATODA: RHABDITIDAE)

1984 ◽  
Vol 116 (2) ◽  
pp. 285-287
Author(s):  
Jean R. Finney ◽  
Gordon F. Bennett
Keyword(s):  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Control Agent ◽  
Balsam Fir ◽  
Larval Instars ◽  
First Instar ◽  
Cryptic Habitats ◽  
Chemical Pesticides ◽  
Third Instar Larvae

Finney et al. (1982) reported on the susceptibility of the 4th to 6th larval instars and pupae of Choristoneura fumiferana (Clemens) to Heterorhabditis heliothidis (Khan, Brooks and Hirschmann). This report describes the susceptibility of the first three larval instars to the nematode. First-instar larvae search for suitable sites where they spin hibernacula in which they molt and overwinter as second-instar larvae. Most third-instar larvae burrow within the balsam fir buds. All these stages occupy cryptic habitats to which delivery of chemical pesticides is a problem. Rhabditid nematodes, which can actively seek out a target insect, may prove a more useful control agent under these circumstances.

scholarly journals Relationship of spruce budworm (Choristoneura fumiferana) emergence and balsam fir (Abies balsamea) bud flush to climate indices

2009 ◽  
Vol 85 (4) ◽  
pp. 625-630 ◽  
Author(s):  
Alan J Thomson
Keyword(s):  
Choristoneura Fumiferana ◽  
Abies Balsamea ◽  
Spruce Budworm ◽  
Balsam Fir ◽  
Climate Indices ◽  
Published Data ◽  
Eastern Canada ◽  
The Pacific ◽  
Larval Emergence ◽  
Temperature Records

Temperature records from weather stations across eastern Canada were used with published data on degree-day requirements for spruce budworm larval emergence and balsam fir bud flush to estimate historical patterns of larval emergence and timing of bud flush. The pattern of association was studied using Response Surface Analysis and was found to vary from west to east. April values of the Pacific/North American (PNA) pattern, Pacific Decadal Oscillation (PDO) and Northern Annular Mode (NAM) climate indices showed the most significant relationship to both emergence and bud flush in the 2 Ontario stations, while May values of the PDO and Eastern Pacific (EP) indices were most significant in the 4 Quebec and New Brunswick locations. Key words: phenology, balsam fir, teleconnections

scholarly journals The Gut Microbiome of the Eastern Spruce Budworm Does Not Influence Larval Growth or Survival

2018 ◽  
Author(s):  
Melbert T. Schwarz ◽  
Daniel Kneeshaw ◽  
Steven W. Kembel
Keyword(s):  
Microbial Community ◽  
Microbial Communities ◽  
Research Effort ◽  
Choristoneura Fumiferana ◽  
Larval Growth ◽  
Spruce Budworm ◽  
Eastern Canada ◽  
Growth And Survival ◽  
Eastern Spruce Budworm ◽  
Host Microbe Interactions

ABSTRACTMicrobial communities have been shown to play an important role for host health in mammals, especially humans. It is thought that microbes could play an equally important role in other animal hosts such as insects. A growing body of evidence seems to support this, however most of the research effort in understanding host-microbe interactions in insects has been focused on a few well-studied groups such as bees, cockroaches and termites. We studied the effects of the gut-associated microbial community on the growth and survival of the eastern spruce budworm Choristoneura fumiferana, an economically important lepidopteran forest pest in eastern Canada and the northeastern United States. Contrary to our expectations, the gut microbial community of spruce budworm larvae does not appear to influence host growth or survival. Our results agree with the hypothesis that lepidopteran larvae lack resident microbial communities and are not nutritionally dependent on bacterial symbionts.

Regeneration and stand development following a spruce budworm outbreak, spruce budworm inspired harvest, and salvage harvest

2012 ◽  
Vol 42 (10) ◽  
pp. 1759-1770 ◽  
Author(s):  
C. Eiry Spence ◽  
David A. MacLean
Keyword(s):  
Species Composition ◽  
Structural Characteristics ◽  
Choristoneura Fumiferana ◽  
Abies Balsamea ◽  
Canopy Cover ◽  
Spruce Budworm ◽  
Balsam Fir ◽  
Stand Development ◽  
Eastern Canada ◽  
Precommercial Thinning

Spruce budworm ( Choristoneura fumiferana (Clemens)) (SBW) outbreaks are a major disturbance that influence stand dynamics and succession in balsam fir ( Abies balsamea (L.) Mill.) dominated forests of eastern Canada. We used stand and regeneration data collected from five plots in each of one immature and five mature stands before, during, and 30 years following the last major SBW outbreak in the Cape Breton Highlands to examine the role of stand and regeneration characteristics in shaping future stand development. Comparisons were also made between regeneration in four SBW outbreak stands versus two SBW salvage stands, with and without a subsequent precommercial thinning, and with 25 plots that underwent SBW emulation harvest. In mature unharvested balsam fir stands, species composition 30 years following the SBW outbreak was closely related to predisturbance species composition, and in immature fir stands, hardwood composition increased from 0% to 4%–27%. Species composition in harvested stands varied depending on whether intolerant hardwoods had been precommercially thinned, where thinned stands had 30% less hardwood 30 years postdisturbance than unthinned stands. Seedling density decreased by 17%–85% from 1979 to 1989 in all SBW outbreak stands, but average seedling height increased by 17%–500% as live canopy cover decreased from an average of 50% to 4%. Results suggest that advanced regeneration should be protected during harvest of balsam fir dominated stands, post-outbreak precommercial thinning will increase tree growth, and live tree retention can help develop late-seral structural characteristics in second-growth stands.

scholarly journals Tracking insect outbreaks: a case study of community-assisted moth monitoring using sex pheromone traps

FACETS ◽  
2020 ◽  
Vol 5 (1) ◽  
pp. 91-104
Author(s):  
R. Drew Carleton ◽  
Emily Owens ◽  
Holly Blaquière ◽  
Stéphane Bourassa ◽  
Joseph J. Bowden ◽  
...  
Keyword(s):  
Choristoneura Fumiferana ◽  
Urban Forestry ◽  
Spruce Budworm ◽  
Pheromone Trap ◽  
Flight Period ◽  
Insect Outbreaks ◽  
Eastern Canada ◽  
Long Distance ◽  
Sex Pheromone Traps ◽  
Community Science

Insect outbreaks can cover vast geographic areas making it onerous to cost-effectively monitor populations to address management or ecological questions. Community science (or citizen science), which entails engaging the public to assist with data collection, provides a possible solution to this challenge for the spruce budworm ( Choristoneura fumiferana Clemens), a major defoliating pest in North America. Here, we lay out the Budworm Tracker Program, a contributory community science program developed to help monitor spruce budworm moths throughout eastern Canada. The program outsources free pheromone trap kits to volunteers who periodically check and collect moths from their traps throughout the budworm flight period, then return them in a prepaid envelope to the organizers. Over three years, the program engaged an average of 216–375 volunteers and yielded a data return rate of 68%–89%, for a total of 16 311–54 525 moths per year. Volunteer retention among years was 71%–89%. Data from this program offer compelling evidence for the range of long-distance moth dispersal. Although our program was designed for spruce budworm, this template could easily be adapted for forestry, urban forestry, and agricultural systems to monitor any of the numerous organisms for which there is an established trapping method.

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