The tactic and kinetic responses of adult Dendroctonus ponderosae Hopkins were studied under varying conditions of light, temperature, humidity, gravity, and with different visual forms. Newly emerged adult Dendroctonus ponderosae Hopk. were attracted by high light intensity and utilized spot sources of light and surrounding objects, but not polarized light, for orientation. Flying adults were positively phototactic unless warmed above 35 °C; egg-laying adults were negatively phototactic. High temperatures and light intensities increased the frequency of flights. The beetles were negatively geotropic but this could be masked by the attraction to light. Dark objects on a light background were attractive; the size of the object was important while the shape was not.Temperature influenced orientation to some extent but its influence on rate of activity was far more pronounced; rate of walk followed a linear relationship with temperature. Humidity also affected orientation and rate of walk to some extent, although its effect was usually masked by other environmental factors.

The relationship of western spruce budworm outbreaks and population collapse to weather parameters was examined using long term weather records from two stations in the budworm outbreak area of British Columbia and outbreak patterns obtained from Forest Insect and Disease Survey records and from tree stem analyses.Outbreaks were associated with warm dry summers in conjunction with synchrony of larval emergence and bud flush. Collapse of the last two outbreaks was clearly associated with extreme high temperatures following moth flight. Collapse of the earlier outbreaks may have been due to asynchrony between larval emergence and bud flush.

The Canadian Entomologist 127: 813-830 (1995) Male moths of Choristoneura occidentalis Freeman, C. biennis Freeman, C.fumiferana (Clemens), and C. orae Freeman were caught in pheromone-baited traps. Ten traps were placed at each site, five baited with an aldehyde lure and five with an acetate lure. This procedure permitted separation of species based on the specific chemical lure and also provided specimens for further study of morphological and isozyme differences. The color of the forewings, presence or absence of spicules on the aedeagus, and a specific allozyme frequency were determined on selected specimens where these characteristics were useful in separating species at a particular site. Distributions of all species were more extensive than previously known, sometimes adding hundreds of kilometres to the recorded range. Areas of sympahy were identified and the fidelity and usefulness of characteristics for separating species in areas of overlap were discussed.