Distribution, species composition, and incidence of egg parasitoids of the forest tent caterpillar (Lepidoptera: Lasiocampidae), during a widespread outbreak in the Canadian prairies

2011 ◽  
Vol 143 (3) ◽  
pp. 272-278 ◽  
Author(s):  
Daryl J. Williams ◽  
David W. Langor

AbstractEgg bands of the forest tent caterpillar,Malacosoma disstriaHübner, were sampled across a wide area of the Canadian prairie provinces during a large-scale outbreak in 1989 and 1990 to examine the incidence and distribution of egg parasitoids (Hymenoptera). Data on the parasitoid species found and the incidence and frequency of parasitism in three habitat types is presented. Three species of egg parasitoids were recovered,Telenomus clisiocampaeRiley (Scelionidae),Ooencyrtus clisiocampae(Ashmead) (Encyrtidae), andBaryscapus malacosomae(Girault) (Eulophidae). Differences in the number of species occurring per egg band and the percent of parasitism were found among habitat types. These differences are correlated to the amount of spumaline cover on egg bands, which also varied among habitat types.

1998 ◽  
Vol 130 (5) ◽  
pp. 703-714 ◽  
Author(s):  
Jens Roland ◽  
Brendan G. Mackey ◽  
Barry Cooke

AbstractWe examined the effect of forest structure and climate on large-scale and long-term patterns of outbreaks of forest tent caterpillar, Malacosoma disstria Hbn., across central Ontario. This was done using previously published data on outbreak duration and forest heterogeneity, combined with high-resolution climatic data simulated by the recently developed Ontario Climate Model. Our analysis, which eliminates some of the spatially confounding effects of forest structure and climate, suggests that both the predicted long-term temperature minimum for the coldest month and the predicted growing degree-days in the first 6 weeks of the growing season are important determinants of outbreak duration, with colder weather being associated with shorter outbreaks. Forest heterogeneity accounts for more variation in outbreak duration than either of the climatic variables.


2003 ◽  
Vol 135 (3) ◽  
pp. 359-378 ◽  
Author(s):  
Melanie J. Filotas ◽  
Ann E. Hajek ◽  
Richard A. Humber

AbstractFuria gastropachaecomb. nov. (= Furia crustosa MacLeod et Tyrrell) has long been associated with declines in populations of the forest tent caterpillar, Malacosoma disstria Hübner; however, its prevalence and impact on host populations have never been documented. We clarify the nomenclature for this species, which has previously been called F. crustosa, and describe the morphology of F. gastropachae isolates from Maryland and New York. Epizootics of F. gastropachae were studied in M. disstria populations in New York and Maryland, United States of America. Prevalence (mean ± SE) of F. gastropachae in late fifth instar larvae in New York was 25.6 ± 7.8% compared with 22.2 ± 11.3% infection by virus and 23.3 ± 8.4% parasitism. In Maryland, F. gastropachae was not found in early instars and its incidence in fourth and fifth instars was 14.5 ± 7.3 and 21.6 ± 17.6%, respectively. Dipteran parasitoids were also important natural enemies with 38.3 ± 3.0 and 17.9 ± 1.4% parasitism in fourth and fifth instars, respectively. Virus was found in fewer than 5% of larvae collected. Furia gastropachae showed a marked tendency toward resting spore production in infected larvae, with 100% of larvae collected in New York and >80% of larvae collected in Maryland producing resting spores, either alone or in combination with conidia. The appearance of cadavers of larvae dying from fungal and viral infections was similar. Of 13 species of Lepidoptera exposed to F. gastropachae conidia in host-range bioassays, only 3.3% of Danaus plexippus (L.) (Lepidoptera: Danaidae), 5.6% of Pieris rapae (L.) (Lepidoptera: Pieridae), and 3.7% of Manduca sexta (L.) (Lepidoptera: Sphingidae) were successfully infected by this fungus.


1953 ◽  
Vol 85 (8) ◽  
pp. 297-310 ◽  
Author(s):  
C. R. Sullivan ◽  
W. G. Wellington

The forest tent caterpillar, Malacosoma disstria Hbn., and the eastern and western tent caterpillars, M. americanum (Fab.) and M. pluviale (Dyar), are common pests of several species of deciduous trees in Canada. All are colonial during the larval stage, but M. disstria differs from the others in one respect: it does not construct a communal tent. This difference in habit merits special consideration in any comparative study of larval behaviour, particularly in one concerned with the effects of physical factors upon the insects, since a tent modifies the effects of the physical environment considerably. Recently, a series of such studies was carried out, and one part of the work consisted of laboratory and field observations on the light reactions of larvae. The results obtained have raised a number of new questions which unfortunately cannot be answered now, hecause two of the species have been difficult to obtain in quantity since 1950. Nevertheless, the findings are presented here without additional delay, since they are of general interest, and other workers may wish to use them.


1993 ◽  
Vol 71 (8) ◽  
pp. 1511-1515 ◽  
Author(s):  
T. D. Fitzgerald ◽  
F. X. Webster

Behavioral assays show that the steroid 5β-cholestan-3-one, isolated from the abdomen of the larva of the forest tent caterpillar (Malacosoma disstria), constitutes the chemical basis of trail following in this insect. Caterpillars follow artificial trails prepared from solvent dilutions of the compound at rates as low as 10−11 g∙mm−11 of trail, though the true threshold sensitivity is likely to be one or two orders of magnitude lower than this. Fourth-instar caterpillars store an average of 58 ng of the pheromone. Field and laboratory studies indicate that the compound is fully competitive with their authentic trails. The caterpillars are highly sensitive to differences in the concentration of the pheromone, preferring stronger trails to weaker trails. The caterpillars also respond to 5β-cholestane-3,24-dione, a chemical not found in M. disstria but known to be a component of the trail pheromone of the eastern tent caterpillar, Malacosoma americanum.


2005 ◽  
Vol 11 (4) ◽  
pp. 588-599 ◽  
Author(s):  
Jep Agrell ◽  
Brian Kopper ◽  
Evan P. McDonald ◽  
Richard L. Lindroth

1969 ◽  
Vol 101 (12) ◽  
pp. 1269-1285 ◽  
Author(s):  
F. T. Bird

AbstractCytoplasmic polyhedrosis viruses are, in general, more infectious to spruce budworm, Choristoneura fumiferana (Clemens), and forest tent caterpillar, Malacosoma disstria (Hübner), than the nuclear polyhedrosis viruses which affect these insects. The cytoplasmic polyhedrosis viruses interfere with and retard development of the nuclear polyhedrosis viruses.Larvae of both insects, as they grow older, develop resistance to both viruses. Resistance develops more rapidly and to a greater degree against the nuclear polyhedrosis than against the cytoplasmic polyhedrosis viruses.The nuclear polyhedrosis viruses are more lethal than the cytoplasmic polyhedrosis viruses, and all larvae infected with the nuclear polyhedrosis viruses die except those infected so late in larval development that they are able to pupate. Most young larvae infected with the cytoplasmic polyhedrosis virus die or are seriously affected, but infection has progressively less effect as the larvae mature.


1980 ◽  
Vol 58 (2) ◽  
pp. 221-227 ◽  
Author(s):  
Spencer G. Sealy

The response of the northern oriole (Icterus galbula) to an outbreak of the forest tent caterpillar (Malacosoma disstria) on the Delta Beach Ridge, Manitoba, was studied. Orioles responded in 1976 to the increased food supply by feeding on all life stages of the insect and by feeding late instar larvae and pupae to their young. The nesting density doubled in 1977, the 2nd year of the 2-year outbreak, but the caterpillar larvae died off before the orioles' chick-rearing period. The 1978 breeding density was back down to the level of 1976. Clutch sizes and body weights did not change despite the increase and eventual reduction in both food abundance and nesting density. Productivity was lower, and hatching failure and nestling death were higher, at the higher nesting density.


1997 ◽  
Vol 129 (6) ◽  
pp. 991-999 ◽  
Author(s):  
R.W. Nicol ◽  
J.T. Arnason ◽  
B. Helson ◽  
M.M. Abou-Zaid

AbstractLarval growth and pupal parameters of the forest tent caterpillar (Malacosoma disstria Hübner) reared on the foliage of two host trees (Populus tremuloides Michx. and Acer saccharum Marsh.) and one nonhost tree (Acer rubrum L.) were quantified. This was achieved by undertaking a larval development bioassay under controlled laboratory conditions, but using fresh leaves collected in two field seasons. Larvae fed foliage of P. tremuloides grew exponentially and began to pupate after 3 weeks. Larvae fed with A. saccharum gained significantly less weight and had a reduced number of larvae pupate, and the pupae weighed significantly less than their counterparts fed on P. tremuloides. All larvae that were fed the foliage of A. rubrum died within 2 weeks. A nutritional utilization bioassay with fourth-instar larvae revealed that the foliage of A. saccharum has a growth-inhibitory component, whereas that of A. rubrum is antifeedant. Reasons are discussed for the discrepancy between the many reports of A. saccharum being a food host for M. disstria in the field and the laboratory results.


1971 ◽  
Vol 103 (10) ◽  
pp. 1371-1379 ◽  
Author(s):  
R. F. Shepherd ◽  
C. E. Brown

AbstractA sequential egg-band sampling system for predicting defoliation of aspen by the forest tent caterpillar (Malacosoma disstria Hbn.) is described and its accuracy assessed. A probability method of predicting defoliation from the stage of the outbreak in each local area is also established. A third method, which promises to be the most accurate and consistent, is proposed. In this last system, egg-mass density is established and related to defoliation levels which are adjusted depending upon age of outbreak.


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