Journal of the Entomological Society of British Columbia
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The distribution of two species of Cenocorixa in inland saline lakes of British Columbia
Get PDFThe distribution of <i>Cenocorixa bifida</i> (Hung.) and <i>C. expleta</i> (Uhler) in British Columbia is summarized. The distribution pattern in a series of inland saline lakes in the central interior of the province is described. All water bodies are in the flight range of the two species, and seem to be colonized by them at random. However, <i>C. expleta</i> occurs and breeds only in saline waters, whereas <i>C. bifida</i> lives and breeds in fresh and moderately saline environments. <i>C. expleta</i> has been found only in waters with a conductivity between 3,900 and 29,000 micromhos/cm. (at 25∞C): <i>C. bifida</i> occurs only in waters with a conductivity between 20 and 20,000 micromhos/cm. The distribution appears to be correlated with salinity and not with other features of the environment such as area of water body, mean depth, maximum depth, etc
Some observations on flight in Oncopeltus fasciatus (Dallas) (Hemiptera: Lygaeidae)
No full text<i>Oncopeltus fasciatus</i> (Dallas) is a typical Hemipteran with forewings modified to form hemielytra and membraneous hind-wings. During flight, these two pairs of wings are linked together by a wing coupling apparatus. Observations were made on normal insects and insects with either fore- or hind-wings removed. The experiments demonstrated that the mesothorax with the fore-wings is the most important segment of the pterothorax in this insect. It was shown that the fore-wings provide the main propulsive force for flight and also provide much of the lift: the hind-wings provide extra-surface for lift, but this is effective only if the wings are coupled together. As in the Lepidoptera and Hymenoptera, where the two pairs of wings are also linked together by a wing coupling apparatus, it appears that the musculature of the mesothorax may be the "driving force" for both pairs of wings
Hymenopterous parasites of the hemlock sawfly, Neodiprion tsugae Middleton, in southeast Alaska, with a key to larval remains
No full textA key is supplied to identify parasitic Hymenoptera reared from hemlock sawfly cocoons in southeast Alaska. The key is based on the size of the exit hole in the host cocoon, and characters visible on the final-instal' larval skin. Brief biologIcal and descriptive notes are given for each species appearing in the key
Acceptability of cultivars of highbush Blueberry at varying temperatures by adult black vine weevils (Col.: Curculionidae)
Get PDFAdults of the black vine weevil,<i>Otiorhynchus (Brachyrhinus) sulcatus</i> (F.), fed and oviposited at normal, expected rates when fed excised foliage of the acceptable highbush blueberry cultivars, June and Stanley, in variable temperature regimes of 7 to 15, mean 10; 12 to 19, mean 15; and 16 to 29, mean 22C. However, on the unacceptable cultivars, Cabot and Weymouth, they laid some eggs at the high and very few eggs at the medium regimes, whereas in earlier work they laid no eggs at a constant 20C. These results indicate that Cabot and Weymouth provide barely adequate nutrition to the weevils and that environmental stresses such as a constant 20C demand more nutrients than the unacceptable cultivars can provide. Variable conditions, probably due to a lower turn-over rate during the cool periods, allow the insect to obtain the nutrients necessary for fat body development and some oviposition
Toxicity of insecticides to two strains of Hylemya platura (Meig.) (Anthomyidae: Diptera)
Get PDFUsing the topical-application and impregnated-paper methods baseline toxicity data were obtained for male and female flies of a susceptible and a cyclodiene-insecticide resistant strain of the seed-corn maggot, <i>Hylemya platura</i> (Meig.). As shown by topical application the resistance factor with dieldrin for male and female flies was 337.8 and 342.7 respectively. However, the LC50 by exposure to dieldrin-impregnated papers could not be obtained for the resistant strain at the concentrations tested. There was no cross-resistance to six other insecticides: two from each of the major groups of organocarbamate, organochlorine, and organophosphorous insecticides. Both methods are useful for determining the toxicity of insecticides and offer ways for agriculturists to determine if spray practices have failed or were faulty, or if resistance is developing within a species
Ecological notes on Orthoptera (S. Str.) in British Columbia
No full textCollections and observations were made of the grasshoppers of the semi-arid Okanagan Valley of British Columbia, during August and September 1969. The habitats. frequency and local distribution of 37 species are discussed, based on 40 collecting sites
Understory plants as indicators of grand fir mortality due to the fir engraver
Get PDFMortality of grand fir trees, caused by the fir engraver, <i>Scolytus ventralis</i>, was monitored during 3 years on ten 0.1-acre (0.04 ha) circular plots in each of nine stands in northern Idaho. Understory vegetation was sampled on each plot on the basis of circular subplots of 0.03 acre (0.012 ha). Analyses showed four species to be strongly correlated with high and two with low tree mortality. The interaction between these groups of plant species provided a variable that increased as the proportion of high- to low-hazard plants increased. Various linear and nonlinear expressions were tested between the two plant groups and their interaction regressed against killed trees per acre. The plant group interaction term accounted for the most variation (r2=0.914) and produced the lowest standard error of the estimate (1.55). The equation for this variable took the form Y = 2.291 + 0.111ex. where X=plant group interaction. This equation provides an indication of the susceptibility of grand fir stands to mortality caused by the fir engraver
Efficacy of insecticides against geometrid larvae, Operophtera spp., on southern Vancouver Island, British Columbia
Get PDFPermethrin, acephate, diazinon, malathion, endosulfan , methoxychlor , Imidan, naled and a spray containing surfactant only were the most effective treatments for control of winter moth, <i>Operophtera brumata</i> (L. ), and Bruce spanworm, <i>O. bruceata</i> (Hulst), on apple in the tight cluster bud stage. Resmethrin, trichlorfon, and Dipel and Thuricide formulations of <i>Bacillus thuringiensis</i> were less effective. The growth disruptor, Dimilin, provided good control at the pink bud stage. At this same stage, sprays with surfactant only were no better than untreated controls