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1.
EMMA DESPLAND MARIA GUNDERSEN SIMON P. DAOUST BRIAN J. MADER NATHALIE DELVAS PAUL J. ALBERT ERIC BAUCE 《Physiological Entomology》2011,36(1):39-46
The pattern of feeding of Eastern spruce budworm Choristoneura fumiferana (Clem.) (Lepidoptera, Tortricidae) is compared on foliage from white spruce Picea glauca (Moench) Voss. (Pinaceae) trees previously determined to be susceptible and resistant to defoliation by budworm. No differences are observed in electrophysiological responses from taste sensilla to aqueous extracts of the two foliage types, nor is there a preference for either extract type in a choice test. Acetone extracts from the two foliage types are both preferred to a control sucrose solution, although neither elicits a preference relative to the other. These results suggest that there is no difference in phagostimulatory power of internal leaf contents of the two foliage types. Longer‐term observation of feeding behaviour in a no‐choice situation shows no difference in meal duration, confirming the lack of difference in phagostimulatory power. However, on average, intermeal intervals are twice as long on the resistant foliage, leading to an overall lower food consumption during the assay. This result suggests an anti‐digestive or toxic effect of the resistant foliage that slows behaviour and limits food intake. Previous research has shown that waxes of the resistant foliage deter initiation of feeding by the spruce budworm and that this foliage contains higher levels of tannins and monoterpenes. The data suggest that the resistant foliage contains a post‐ingestive second line of defence against the spruce budworm. 相似文献
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3.
SUMMARY. 1, The distribution patterns of twenty-one species of heptageniid mayflies were examined in Saskatchewan and west-central Manitoba, Canada. Presence/absence data from 174 stream sites were analysed using two complementary multivariate techniques, classification (Ward's method with Euclidean distance) and ordination (detrended correspondence analysis).
2. Multivariate analyses revealed two large, distinct groups of sites within the study area. The first included sites characterized by the presence of Heptagenia elegantula (Eaton) and Stenonema terminatum (Walsh). The second included sites characterized by the presence of Stenonema vicarium (Walker), Leucrocuta hebe (McDunnough) and/or Nixe species. The two groups contained, respectively, three and four subgroups.
3. Groups and subgroups defined by multivariate analyses were compared using large-scale environmental features obtained from topographic and other maps. Differences in environmental features between the two groups were mainly in stream order, terrestrial vegetation and annual number of degree-days (calculated from air temperature). The first group could be characterized as warm, large river habitat in grassland and parkland vegetation regions. The second included cooler, small to midsized streams and rivers in boreal forest. Most differences among subgroups were also in stream order, terrestrial vegetation and degree-days, although some subgroups in the second group differed also in stream gradient.
4. The observed groups and subgroups were not associated with drainage basins. 相似文献
2. Multivariate analyses revealed two large, distinct groups of sites within the study area. The first included sites characterized by the presence of Heptagenia elegantula (Eaton) and Stenonema terminatum (Walsh). The second included sites characterized by the presence of Stenonema vicarium (Walker), Leucrocuta hebe (McDunnough) and/or Nixe species. The two groups contained, respectively, three and four subgroups.
3. Groups and subgroups defined by multivariate analyses were compared using large-scale environmental features obtained from topographic and other maps. Differences in environmental features between the two groups were mainly in stream order, terrestrial vegetation and annual number of degree-days (calculated from air temperature). The first group could be characterized as warm, large river habitat in grassland and parkland vegetation regions. The second included cooler, small to midsized streams and rivers in boreal forest. Most differences among subgroups were also in stream order, terrestrial vegetation and degree-days, although some subgroups in the second group differed also in stream gradient.
4. The observed groups and subgroups were not associated with drainage basins. 相似文献
4.
A scrutiny of the literature shows that the ctenophore Haeckelia (= Euchlora) ruba has only kleptocnidae and that Hydroctena salenskii is a ctenophore without special cnidarian affinities. The “missing links” between cnidarians and ctenophores have thus turned out to be based on misinterpretations and must be excluded from future discussions on phylogeny. 相似文献
5.
DICKY S. YU ERIC G. KOKKO JOHN R. BARRON G. BRUCE SCHAALJE BRENT E. GOWEN 《Systematic Entomology》1992,17(4):389-395
Abstract. Image analysis was used to measure the morphological characters of wings of five species of Canadian Itoplectis (Ichneumonidae). The procedure to digitize and measure various elements of the wings with an image analyser is outlined. Specimens were assigned to species by discriminant analysis and independent univariate comparisons of 144 characters from cells, veins and vertices. All the fifty specimens used were assigned to the correct species by both methods. Image analysis of ichneumonid wings is an effective alternative to the conventional identification system. 相似文献
6.
GEORGE STAFF ERIC N. POWELL ROBERT J. STANTON JR. HAYS CUMMINS 《Lethaia: An International Journal of Palaeontology and Stratigraphy》1985,18(3):209-232
In general, more of the biomass of the community is preserved than is its numerical abundance. Thus, the paleontologist, on the average, works with more of the community when biomass is used. Community characteristics such as taxon dominance and habitat proportions are at least as accurately derived from biomass as numerical abundance. The use of biomass is clearly more appropriate in describing energy flow and trophic proportions. Whenever possible, biomass should be used as a complement to numerical abundance in future paleoecologic reconstructions. 相似文献
7.
Putrescine, spermidine, and spermine content were analysed inzygotic embryos of barley (Hordeum vulgare L.). Changes in polyaminecontent were observed during zygotic embryo growth. In two cultivars,Bomi and Golden Promise, the totalpolyamine content in the embryos was 2.62.9 nmol mg1fresh weight 10 d after anthesis, the highest content observed.It dropped to 1.3 nmol mg1 fresh weight 14 d after anthesis.This drop was caused by decreases in all three polyamine concentrations.From 14 to 35 d after anthesis the putrescine content continuedto decrease while the spermidine and spermine content increased,thus the total polyamine content remained constant until 35d after anthesis. The mutant Ris? 1508 showeda constant polyamine content around 1.3 nmol mg1 freshweight from 14 to 35 d after anthesis. The polyamine patternwas conserved in all three lines throughout the period of investigationshowing a spermidine content higher than putrescine contentwhich was, in turn, higher or equal to the spermine content.The polyamine content measured as nmol µg1 proteindecreased from 14 to 21 d post anthesis in all three lines,because the protein content (µg mg1 fresh weight)increased during the period. In dedifferentiating zygotic embryoscultured in vitro the putrescine content (nmol mg1 freshweight) rose by a factor of nine and the spermidine contentdoubled within the first week of cultivation, whereas sperminecontent did not change. For embryoderived calli a repeated patternof change in polyamine content was observed throughout the subculturingperiod. Key words: Polyamines, Hordeum vulgare L., embryo development 相似文献
8.
Northern red oak (Quercus rubra L.) seedlings were grown for63 d in a complete nutrient solution (pH 3.8) containing oneof three concentrations of Al (0, 0.75 or 2-0 mol m3)and either 10 or 250 mmol m3 Ca. Of all solution variables,the In of (Al3+)/(Ca2+), the solution activities ratio, wasmost closely correlated with declines in shoot and root growth.Ln (Al3+)/(Ca2+) also most closely predicted leaf and root [Mg],[Al], and [Al]/[Ca]. These three variables in turn were closelyrelated to growth. Toxic levels of (Al3+) and (Al3+)/(Ca2+)in solution are compared to levels in forest soils. Key words: Al phytotoxicity, Al x Ca interaction, Quercus rubra 相似文献
9.
ERIC A. KWEI 《Zoological Journal of the Linnean Society》1978,64(2):151-175
Blue crabs Callinectes latimanus (Rath.) trapped from two lagoons were sexed, measured and weighed. The eggs of the mature females were counted to determine fecundity, and the spermatophores of the males were counted to determine the size of sexual maturity. Sizes at maturity of both male and female crabs were determined. The methods employed and the results are discussed. 相似文献
10.
ERIC BAILLY RONAN JAMBOU JEAN SAVEL GINETTE JAUREGUIBERRY 《The Journal of eukaryotic microbiology》1992,39(5):593-599
ABSTRACT We investigated the effect of a cysteine proteinase inhibitor (E-64) and an aspartyl proteinase inhibitor (Pepstatin A) on asexual erythrocytic stages of Plasmodium falciparum in culture. These two protease inhibitors showed different patterns of activity. E-64 acted preferentially against trophozoite and schizont stages. After 48 h incubation at high concentrations of E-64 (28, 140, 280 μM), growth was totally abolished and the parasites presented characteristic enlarged food vacuoles. Morphological alterations were also seen after shorter incubation periods (6 h at 28 μM) or 12 h at the inhibitory concentration 50% (12 μM), but an additional culture period (24 h) in inhibitor-free medium allowed normal parasite development, demonstrating a parasitostatic effect. E-64 acts on parasite multiplication; the normal merozoite maturation was altered and the normal reinvasion process partially impaired. Pepstatin A used at the inhibitory concentration 50% (4 μM) killed the parasites before trophozoite development and had a major effect on schizonts maturation. No altered parasite development occurred during an additional culture period without Pepstatin A, demonstrating a parasiticidal effect. E-64 and Pepstatin A used in combination inhibit the parasite growth with a strong synergistic effect. 相似文献